Eunorau FLASH 2.0 Review 2026: 1000W Mid-Drive, $2,124

82–92 lb · CST 20 × 4.0 fat tires · TruckRun 1,000 W mid-drive · 220 N·m · Shimano 8-speed · full suspension · 832 Wh · 20 mph · 440 lb payload · 30.7 in standover · 33.1 in bench seat · riders 5'2"–6'4" · $2,499 in Moon Black or Lunar Dust · ridden in fall mud and rain · verified September 30, 2026

Quick Answer: The Eunorau FLASH 2.0 is a $2,124 full-suspension mid-drive step-over on 20 × 4.0 fat tires: a TruckRun 1,000 W motor through eight Shimano gears, an 80 mm fork, a coil rear shock and bays for three packs. On the throttle, a 180 lb rider covers about 57 miles at 12 mph on the standard 832 Wh pack.

The gears pay on grades: up an 8% street the model holds 17.1 mph with 180 lb aboard, where the one-hub FLASH LITE 2.0 on the same frame holds 13.9 (the climb table). We rode it through a wet fall in mud and rain, and both videos are on this page.

Its printed 1,000 W, throttle and 20 mph fit 4 of 51 jurisdictions' e-bike definitions on September 30, 2026 (the law section).

What's on this page

Twenty-six sections: who the FLASH 2.0 suits, our ride, its drive, parts and frame, the other FLASH models, range and payload, your fit, the law at 1,000 W, ownership, and the verdict.

• Who the FLASH 2.0 is for
• We rode it: a wet fall, in mud and in rain
• How we verified this Eunorau FLASH 2.0 review
• Eunorau FLASH 2.0 specifications
• The TruckRun mid-drive, eight gears and the throttle
• Full suspension, the brakes and the display
• The frame, the bench and room for three packs
• FLASH 2.0 or another FLASH
• How far the FLASH 2.0 goes, gear by gear
• Two riders and 440 lb
• Will the FLASH 2.0 fit you?
• The Mercer fit test
• What the law calls a 1,000 W mid-drive with a throttle
• Charging and battery care
• Where Eunorau prints a figure two ways
• Has it been recalled?
• Is it UL certified?
• Warranty, and who handles a claim
• Buying it from us
• The honest ledger
• Who should buy it
• Before you buy: the checklist
• Limitations of this review
• The source register
• Frequently asked questions
• The bottom line

Who the FLASH 2.0 is for

Eunorau's own photograph of the Moon Black, set on a pale studio sweep we built around it for this card. The $2,499 and the 1,000 W are Eunorau's figures; the range section works out the 57 miles.

The FLASH 2.0 suits you if you want the moped stance and the long bench with a motor that works through gears: steep streets, a passenger, broken pavement, long days. Eunorau's page calls the motor "a center-mounted drive which makes the bike's center of gravity not change greatly", and pairs it with "a 8 speed derailleur".

The Lunar Dust from the chain side, as Eunorau photographed it: the motor at the cranks, the rear shock under the bench, the eight-speed cluster at the back wheel.

On Eunorau's own triage, a rider who wants "full suspension comfort and more power, budget allows" belongs on the FLASH 2.0 (its FAQ on the FLASH LITE 2.0 page). Our ride adds a condition: the gears ask you to shift, so the stop-and-go commuter reads the FLASH LITE 2.0 review first.

Shorter than about 5'5"? Our FLASH LITE ST review covers the 17.5-inch step-through.

We rode it: a wet fall, in mud and in rain

The riding on this page is ours; every performance figure is Eunorau's published figure or computed from it. We rode the FLASH 2.0 through a wet fall, across a plowed field in the mud and in the rain, and when the test was over the bike was sold to a food-delivery courier who has been hard on it since. Both videos are in this section, with the courier's record between them.

What the torque does from a standstill

220 N·m is a number until you open the throttle. From a stop, on the throttle alone, the front wheel comes up. The lift is what Eunorau's torque figure looks like from a standstill, and it is the reason to learn the throttle seated and on flat ground before you learn it on a hill, with the torque-sensor assist doing the work until you have.

On our rides, loaded and ridden hard, the motor did not overheat once, and it was quiet. Eunorau publishes the sensor behind the assist as a "high-sensitivity torque sensor and speed sensor", and on the road that reads as assist arriving in proportion to how hard you press, with no surge. A new rider wants that behavior.

The same page publishes "shift detection that was combined with the motor", and you feel it: on each gear change the power pauses for a beat so the chain moves under no load, and to a rider who likes manual cars it feels like a gear change in one.

What it will not do is spare you the shifting. In stop-and-go traffic a mid-drive asks for a gear change at every light, and if that is your riding, the rear-hub FLASH LITE 2.0 on the same frame is the better tool. Ride this one like a manual car, in the right gear for the speed and the slope, and the gearing does what our motor guide says a mid-drive is for.

The frame, the welds, and what photographs hide

In person the bike looks more expensive than its photographs suggest, and the welds are the reason. The weld job around the frame is, in the rider's word, phenomenal, the frame is heavy-duty in the hand, and the Moon Black of the bike in the footage is a deep blue. Off pavement you listen for anything loose, because on a full-suspension frame anything loose announces itself over the first rut. Nothing did.

It felt as solid as the Himiway D7 Pro we have also ridden, which is the bike we hold that feeling against. The suspension is the other thing you feel: Eunorau publishes a KZ-209 coil shock, 290 mm and rated 1,000 lb, under an 80 mm EXSHO fork, and on the field both could be felt doing their work.

Rain, mud, and the tire it ships with

In the rain it was stable; in the mud it was slippery. The stock CST 20 × 4.0 is a moped-style tread that says so on its sidewall, and on the plowed field it slid in the wet soil.

If mud is your regular surface, budget a knobbier tire for it before the first fall; if your surface is road, path and gravel, leave the tire alone. Eunorau sells a $59 FLASH fender and a $79 fender and lampshade kit that we do not stock; if a wet fall is your riding, tell us and we will say where to get one before the bike arrives.

Two riders, hours in the saddle, and the throttle

The saddle fits two people, and the motor has the torque to pull two up a very steep hill. The judgment is the rider's, from the saddle, and it agrees with Eunorau, which sells the bike for two, writing that "the extra weight of a passenger is no problem", and publishes a 440 lb total payload; the checks to make before you carry anyone, your state's passenger rule among them, are in the payload section.

The rack carries cargo and nothing else: Eunorau's own rear rack for the FLASH is $59, holds "up to 25 kg (55 lbs)", and its listing reads "Strictly for gear. NOT recommended for passengers or sitting."

Hours in that saddle in cold, wet weather left no soreness, and that verdict comes from a rider who lives with chronic pain and knows that cold and damp are when it flares. Photographs make every long bench seat look like every other; they are no more alike than two chairs are.

The one control we would change is the throttle. Eunorau fits a thumb throttle, and on our long throttle-only stretches the thumb tired; we would choose a twist throttle. The answer on the bike as it ships is the torque-sensor assist, which does the same work for a rider who keeps pedaling.

What happened after the test

As of September 19, 2026, one breakdown, on a bike ridden hard for food delivery. The test bike was sold to a courier, and the one failure so far was the front hydraulic brake line. Eunorau covered the part and shipped it promptly, and a Eunorau technician was reachable right away, without anyone being put through the wringer. Buy from us and any claim on your bike is ours to run.

What the ride settles

The ride settles what a specification cannot: that the frame and welds are the real thing, that the torque sensor and the shift detection Eunorau publishes are there and do their jobs, that the saddle fits two people, and that one brake line has failed on a bike ridden hard for delivery. The range, speed and climbing figures below come from a model built on Eunorau's published figures, and Limitation 2 records what the ride did not log.

Asked to put it in car terms, the rider's answer is a crew-cab pickup: a second seat, a bed, the torque to move both, and, with the extra packs, the tank to go a long way. The verdict from the saddle is that, as a package, it is the best, because it is modular enough to adapt to your life, and the sections below are where that package gets priced and where the law gets its say.

How we verified this Eunorau FLASH 2.0 review

Every specification here is Eunorau's, read from the FLASH 2.0 product page and its product record on September 26 and again on September 30, 2026. Each figure that takes arithmetic is worked again, and where Eunorau or its motor maker prints a figure two ways, the conflicts table sets out both.

The range and fit models close their sections with the formula and every input (range, fit). The law section screens all 51 jurisdictions at the printed 1,000 W, and the Limitations date each screen and each store read.

We sell the FLASH 2.0, and the honest ledger sends every rider it suits less well to one of our bikes that fits better. Milad Ghobadibeygvand, BScN (Western University, 2014), rode it and wrote this; send corrections to corrections@redtailebikes.com.

Eunorau FLASH 2.0 specifications

Each row is Eunorau's figure as its page and record read on September 26 and 30, 2026.

The seven lettered geometry rows on the FLASH 2.0's page:

Read from the FLASH 2.0 page on September 30, 2026, inch figures as Eunorau gives them. Row B prints two figures that disagree; the conflicts table carries both.

The TruckRun mid-drive, eight gears and the throttle

The motor sits at the cranks and turns the 44-tooth chainring, so its power reaches the back wheel through the same eight gears your legs use. Eunorau's spec row reads "52V1000W Truckrun Mid Drive Motor with 220N.m Torque" (Eunorau's page), and TruckRun, which quotes Eunorau among its partners, calls its M09 "a true performance beast, available in three versions with 750/1000/1200W" (TruckRun's M09 page).

The drive, cropped from Eunorau's chain-side photograph of the Moon Black: the motor at the bottom bracket, the chainring on its spider, and the crank.

The gear you pick sets how fast the motor turns, and on a climb that decides what the climb costs you. Up an 8% grade at 8 mph on the throttle, the model's 32-tooth cog draws 74 Wh a mile from the pack and the 11-tooth 221 (the gear tables). Shift down before the hill, as you would on a pedal bike.

The thumb throttle moves the bike with no pedaling, and it drives through the gears as well, so the cog you sit in matters on the throttle too. The "0~5 level pedal assist" reads a torque sensor and a speed sensor.

What the gears buy, against the one-hub FLASH LITE 2.0 on the same frame and pack: up an 8% grade with 180 lb aboard, the model holds 17.1 mph on the throttle where the hub holds 13.9. On the flat at 12 mph the hub goes a little further, 61 miles to this bike's 57 (the climb table, our FLASH LITE 2.0 range tables).

Full suspension, the brakes and the display

This is the one FLASH we sell with a rear shock: Eunorau lists a "290MM Double Rear Spring Suspension" under the bench, and the product record names it "KZ-209, 290mm, 1000 lbs". Up front, the EXSHO STRONG-DH fork gives 80 mm of travel with "compression adjustment and lockout" (Eunorau's page).

The back of the bike, cropped from the same chain-side photograph: the coil shock, the eight-cog cluster and derailleur, and the 180 mm rotor.

Both wheels stop on 4-piston hydraulic discs with 180 mm rotors, and each lever cuts the motor as you pull it. Eunorau's copy says the set is "sensitive, but provide efficient and ample force when braking", and on the courier's bike the front line is the one part that has needed replacing (the ride).

The cockpit, cropped from Eunorau's front three-quarter photograph of the Lunar Dust: the bar, the display beside the stem, and the round headlight.

The rest of the kit, as Eunorau lists it:

• The display: a BC281 LCD that Eunorau says is "easy to read even in direct sunlight", with a push mode "to use in the circumstance of pushing the bike uphill".
• The app: "EUNORAU GO", which Eunorau credits with "calorie tracking, trip records, social networking and OTA updates".
• The headlight: it runs from the bike's battery, with its switch on the handlebar control pad.
• The taillight: built into the battery box, and it lights by itself when you brake.
• The fenders: optional; Eunorau sells a FLASH fender at $59.
• Also in the box: aluminum pedals, a manual and a tool kit.

The frame, the bench and room for three packs

The 6061 aluminum frame puts the straight top tube 30.7 inches off the ground and the bench top 33.1 inches (geometry rows E and D). You get on by swinging a leg over the tube, as on a small motorcycle.

The bench over its battery case, cropped from Eunorau's photograph of the Moon Black: the standard pack sits in the case, under the Eunorau name.

Three packs fit, and one ships with the bike. The standard 52V 16Ah pack rides in the case under the bench, and Eunorau's battery row reads "52V16Ah Standard (Optional: Top Tube 52V21Ah / Down Tube 52V17Ah)". Eunorau lists the 21 Ah pack at $699 and 13.9 lb and the 17 Ah at $599 and 10.5 lb, so all three cost you $1,298 more than the bike.

At 82 to 92 lb before any extra pack, the FLASH 2.0 is a two-person lift into a truck bed, so plan on a ramp or street-level parking. It measures 1,740 mm (68.5 in) end to end on a 1,090 mm (43 in) wheelbase (rows G and F), so measure your parking spot and any elevator before it arrives.

The Moon Black from the front, as Eunorau photographed it: the headlight and fork, the motor at the cranks, and the bench high at the back.

It rolls on CST 20 × 4.0 fat tires on 20-inch black alloy wheels with stainless steel spokes (Eunorau's page). Our ride found them steady in rain and slippery in mud (the ride).

FLASH 2.0 or another FLASH

We sell four FLASH models, all on 20 × 4.0 wheels with the 52V 16Ah pack as standard. The FLASH 2.0 is the only one with a mid-drive, gears and a rear shock, on the step-over frame it shares with the FLASH LITE 2.0 and the FLASH AWD 1.0.

Each row from that model's page at Eunorau (FLASH LITE ST, FLASH LITE 2.0, FLASH AWD 1.0, FLASH 2.0), read September 30, 2026, when each of our four prices equaled Eunorau's.

Eunorau's FAQ on the FLASH LITE 2.0 page sorts the step-over three by rider. "Tight budget, mostly city commuting on decent roads" goes to the LITE 2.0, "sand, snow, or steep grades" to the AWD, and "full suspension comfort and more power, budget allows" to the FLASH 2.0.

Choose the FLASH 2.0 for gears and rear suspension at $2,124. Choose the FLASH LITE 2.0 for the same frame on one hub with a few more flat miles at $1,614, and the FLASH AWD 1.0 for a motor in each wheel at $1,784, which its model puts at 18.4 mph up an 8% grade. Our Eunorau collection holds all four, and every e-bike we sell is one click further.

The Lunar Dust from behind, in Eunorau's studio photograph: the taillight at the back of the battery case, the rear shock and the cluster, and the side stand down.

The Moon Black from the non-drive side, photographed by Eunorau: the fork and front rotor nearest the camera, the motor at the cranks, and the shock under the bench.

How far the FLASH 2.0 goes, gear by gear

On level pavement the standard 832 Wh pack carries a 180 lb rider about 57 miles at 12 mph on the throttle, 47 at 15 mph and 33 at the full 20 mph; with the optional 21 Ah second pack the 15 mph ride reaches 109 miles. Up an 8% grade at 8 mph, the 32T cog stretches one charge to 11 miles on the throttle, where the 11T manages 4.

Three steps to your own ride:

1. Find your speed and how hard you pedal in the first two tables.
2. Add about 134 to 157 Wh for each 1,000 feet of climbing, and climb in the big cogs (the gear tables).
3. Correct for your weight and the temperature, then plan on 85% of what remains, the share Eunorau's charging advice leaves in use.

Every figure is one steady ride, priced from TruckRun's published figures for the M09 motor, the 44-tooth chainring Eunorau lists, Shimano's 8-speed tooth counts, drum measurements of fat-bike tires and a cycling-power model validated on the road. The formula subsection lists every input and works one ride from the wheel back to the pack.

How far does it go at my speed?

Speed is the biggest lever you hold: the charge that covers 72 miles at 8 mph on the throttle covers 33 at 20, and going from 15 to 20 mph gives up 29% of it. Air resistance does most of that, because the power to push through the air rises with the cube of speed (Martin et al., 1998).

Throttle only on flat pavement, a 180 lb rider on a 77 °F day; the planning columns keep 15% of each pack, the top of the 10 to 15% Eunorau's FAQ says to recharge at. The gear is the cog the motor drives most cheaply at that speed, with the chainring's rpm beside it. The second pack is Eunorau's optional 52V 21Ah top-tube battery, sold separately.

Pedal lightly and the ride grows: at 15 mph, 75 watts of your own turn 47 miles into 72. Seventy-five watts would move this 82 lb bike and its rider about 9 mph with the motor off; 150 W moves them about 13.

Miles from the 832 Wh pack on a full charge, flat pavement, a 180 lb rider. "Legs alone" means your watts already hold that speed and the motor adds nothing; past 100 miles the table stops counting, since a stop or a headwind will decide the day before the pack does.

Each pedaling column assumes the watts you add yourself. Eunorau's "0~5 level pedal assist" decides how much the torque sensor adds on top, so read the row for the speed you hold and the effort you actually give.

Which gear saves battery?

On the flat, a middle cog: at 15 mph the 24T is the cheapest, and the dearest cog the motor can drive costs 17% more. On a climb, the biggest: up 8% at 8 mph the 32T costs 74 Wh a mile and the 11T 221.

The M09 drives the chainring, so the cog you pick decides how fast the motor turns. TruckRun's figures rate the 1,000 W M09 at 135 rpm; at 20 mph the 24T turns the chainring at 153 rpm and is the cheapest cog, and the 11T costs 23% more, so shifting still pays at the top of the speed range.

Flat pavement, a 180 lb rider, throttle only. A cog is named by its teeth: 32T is the largest and easiest, 11T the smallest and hardest. A cog the motor cannot drive at that speed is left out, because its chainring would have to spin past the motor's no-load speed.

On a hill the order reverses. Holding 8 mph up an 8% grade takes 221 Wh a mile in the 11T and 74 in the 32T, so the wrong cog costs 198% more on the same hill at the same speed. Pedal lightly and the 32T is still the cheapest, with your legs turning 82 rpm.

8 mph, a 180 lb rider; each cell is the battery's cost per mile and the miles the pack gives at that cost.

How much do hills cost, and how steep a hill can it climb?

Every 1,000 feet of climbing draws about 134 Wh from the pack at 4% and 157 at 10%, over and above the same miles on the flat. Raising 262 lb (a 180 lb rider on the 82 lb bike) 1,000 feet takes 99 Wh at the wheel; the chain, the motor and the pack's own losses bring the draw to about 145 Wh.

Spent on nothing but climbing, the 832 Wh pack would lift you about 5,700 feet, and with the second pack about 13,300.

A 180 lb rider. The first two columns are the fastest steady speed the M09 holds at its rated 1,000 W on each grade: 17.1 mph up 8% on the throttle and 18.0 pedaling lightly. The right-hand column is the whole pack spent climbing that grade at 8 mph.

Price a hilly ride as flat miles plus the climb. Twenty miles at 15 mph on the throttle take about 354 Wh; add 2,000 feet at about 145 Wh per 1,000 and the ride uses about 644 Wh, inside the 707 Wh the pack gives with Eunorau's 15% kept.

On the same frame, the one-hub FLASH LITE 2.0 holds 13.9 mph up 8% with 180 lb aboard, where this mid-drive holds 17.1. Eunorau's FAQ names only the MAX-CARGO and the JUMBO as models that charge from pedaling, so descents on the FLASH 2.0 put nothing back. The JUMBO, a stand-up scooter, has our Eunorau JUMBO review to itself.

Does my weight change the range?

On the flat, a little; up a grade, a great deal. From 130 lb to Eunorau's 440 lb limit, a 15 mph throttle ride falls from 51 miles to 34, and an 8% climb at 8 mph pedaling lightly falls from 19 miles to 5.

You and everything you carry; the bike's own 82 lb is added to every row. Eunorau's payload definition counts the rider and the load, and 440 lb is its limit for this bike.

Weight raises what the tires and the hill cost and leaves the air untouched, so the flat rows fall far less than the climbing column. Eunorau prints the bike as 82 to 92 lb and the model carries 82; each extra 10 lb on the bike costs what 10 lb more rider costs, so read the table 10 lb heavier for the top of the range.

Does cold weather drain the battery?

Yes; read the row closest to the temperature you ride in. At freezing, the 15 mph ride pedaling lightly drops from 72 miles to 54, a quarter of the range.

The pack's usable energy against 77 °F and the miles a full pack gives on flat pavement for a 180 lb rider. The central figure is McMaster University's measured LG HG2 cell at a 0.5C discharge, since the record names "LG+" cells without a model; the brackets come from Samsung's data sheets and Casado and colleagues' cold test. The model holds the cells at the air temperature.

Three things add up at 32 °F: the pack gives about 89% of its 77 °F energy, the air is 9% denser, and the tires roll 18% harder.

Do the fat tires cut range?

Less than speed does: on the throttle at 15 mph the ride runs from 43 miles on the slowest fat-bike casing to 54 on the fastest, with 47 at the middle. Eunorau's record names the tire as the CST 20 × 4.0, and no lab or field measurement of it was found.

The model therefore takes the middle of the twelve fat-bike tires Bicycle Rolling Resistance lists, all 26 × 4.00 or wider, and brackets it with the fastest and the slowest.

Miles on one pack for a 180 lb rider on level pavement. Each figure is one tire on Bicycle Rolling Resistance's drum at 29 km/h under 42.5 kg, converted by the site's own formula; a knobbed tread on soft ground rolls harder than any of them.

The model also takes the drag of an upright rider on a cruiser, from Tengattini and Bigazzi's survey; lean onto flat bars like its commuter riders and the 20 mph throttle ride gives 36 miles instead of 33.

Eunorau's 65, 135 and 220 miles, as rides

Eunorau prints "Up to 65 Miles (135 Miles Dual Battery | 220 Miles Triple Battery)" (Eunorau's page). In the model a 180 lb rider on flat ground in still air reaches the one-pack 65 at a steady 10.0 mph on the throttle or 15.7 mph pedaling lightly, and all three packs' 220 miles at 9.9 or 15.7.

The same page ties its 220 miles to "pedal assist 1" with all three packs on board. Spread over the miles, both the 65 and the 220 come to 12.8 Wh a mile, and the two-pack 135 to 14.3.

The steady flat speed at which each pack combination's watt-hours, spread over Eunorau's miles, meet the model's cost per mile; a 180 lb rider at 77 °F using the whole of every pack. The second and third packs are optional and sold separately.

Planned with Eunorau's 15% kept, the standard pack gives 49 miles at 12 mph on the throttle, and with the 21 Ah second pack 112.

How the range tables are computed

A steady speed asks for a steady flow of power at the back wheel. Martin and colleagues' model, validated against riders on a real road in 1998, gives it for still air:

Power at the wheel = v × [ m × g × (Crr × cos θ + sin θ) + ½ × ρ × CdA × v² ]

v is your speed, m you and the bike, g gravity, θ the slope, Crr the tires' rolling resistance (0.0105 is a drag of 1.05% of the weight they carry), ρ the air's density and CdA your drag area, frontal size times shape. The first bracket is the tires and the hill; the second is the air.

From the wheel back to the pack:

1. The chain delivers 97.7% of the chainring's work to the wheel (Martin's drivetrain figure).
2. Your legs supply their watts first and the motor the rest; a pedaling row holds your cadence at 90 rpm or less (Hansen et al., 2021).
3. The gear sets the motor's speed: chainring rpm is the wheel's rpm × the cog's teeth ÷ 44. TruckRun rates the M09's 1,000 W reading at 135 rpm with an efficiency of "≥80" percent and prints no no-load speed, so the model sets it at 172.8 rpm, 135 × 160/125, the no-load-to-rated ratio of Bafang's published M615 at 1,000 W, and caps the torque at Eunorau's 220 N·m.
4. The pack loses a little inside itself, 3.3% at 15 mph, from the battery efficiency Arango, Lopez and Ceren measured on a 48 V mid-drive.

Then watt-hours per mile = the cells' watts ÷ mph, and miles = 832 Wh × the share of energy the temperature leaves ÷ watt-hours per mile.

One ride, worked from the wheel back to the pack: 15 mph, throttle only, a 180 lb rider on level ground. Rolling resistance absorbs 81.8 W and the air 114.2 W, so the wheel needs 196.0 W and the chainring 200.7 W.

In the 24T the chainring spins at 114.7 rpm, and the motor model (2.874 N·m per amp of back-EMF, 0.444 Ω of winding resistance, 1.026 A with no load) supplies 16.7 N·m at 78.1% efficiency, drawing 256.8 W. With the pack's own losses the cells give 265.6 W: 17.7 Wh a mile at 15 mph, and 832 ÷ 17.7 is 47 miles.

The model was checked before any figure here was used. It reproduces Martin's worked example to a tenth of a watt.

No measurement of the M09's efficiency was found, and TruckRun's "≥80" cannot describe its rated point in this model: at 135 of 172.8 rpm the motor's back-voltage is 78% of the pack's, and no winding delivers more than that share of its current's power as work.

The model therefore reads TruckRun's figure as the motor's best efficiency: the surface peaks at 82%, and at the rated point it is 75%, where the surface lands nearest the mid-drive map Arango, Lopez and Ceren measured, within 2.4 points at its seven readings against 9.6 for the 78% ceiling.

At that 78% ceiling the 15 mph throttle ride gives 57 miles instead of 47; with the no-load ratio of the M615's 750 W reading it gives 46, and with the M620's 1,000 W ratio 47. Shimano's 11-30 and 11-34 versions of the same cassette move the 12 mph throttle ride by a tenth of a mile.

Two riders and 440 lb

Eunorau rates the FLASH 2.0 for a 440 lb total payload, and its payload guide says what counts: "Payload covers the rider and anything carried on the bike itself." You, a passenger and your bags all come out of the 440 lb, and the bike's own 82 to 92 lb does not.

Eunorau sells its "Plush Saddle" for "a single rider" or a rider with "a companion", and writes that "with the 52V1000W motor, the extra weight of a passenger is no problem". Our rider judged the bench long enough for two and the motor strong enough to pull two up a steep hill (the ride).

A 200 lb rider with a 150 lb passenger leaves you 90 lb of the rating for bags. At the full 440 lb the model still gives 34 miles at 15 mph on the throttle and 26 at 20 (the weight table).

A rider on a FLASH with the TruckRun mid-drive, in a photograph Eunorau publishes on the FLASH 2.0's page; a down-tube pack is fitted. Eunorau does not name the place.

The rear rack is for bags, never a person. Eunorau's $59 FLASH rack holds "up to 25 kg (55 lbs)", and its listing adds: "No Child Seats: For safety, DO NOT install baby or child seats on this rack."

Whether a passenger may ride is your state's rule, and the 440 lb has to cover you both. California, for one, seats a passenger "upon or astride a separate seat attached thereto", and a child "four years of age or younger, or weighs 40 pounds or less" needs a seat that holds them in and guards them from the moving parts (Cal. Veh. Code § 21204(b)).

Will the FLASH 2.0 fit you?

Eunorau's window for the FLASH 2.0 is 5'2" to 6'4", and two printed heights settle how you stop: 33.1 inches to the top of the bench and 30.7 inches to the top tube.

Standing over that tube with both feet flat takes a barefoot inseam that 11 of 100 people at 5'2" have in the Army's ANSUR II survey; 43 of 100 do at 5'4", and at 5'8" it is 99 of 100.

Staying seated on the bench at a light is harder. In that survey, 78 of 100 people at 5'10" reach the ground with both feet from the bench, and 34 of 100 at 5'8". Below those heights, come forward off the bench onto the tube at a stop, or put a single foot down.

The tables line up 6,068 measured bodies against the heights Eunorau prints, a row every two inches from 5'2" to 6'4". Eunorau's window tells you who the frame is meant for; each row shows how the feet of people your height meet the road.

Finding your own rows takes three steps:

1. Measure your inseam in socks: back against a wall, a hardback book drawn up firmly between your legs, the floor to the book's top edge.
2. Read your height, or the row nearest it, in the bench table and in the top-tube table. An inseam above your row's median reads like a taller row.
3. Do the heel check from the setup section on the first ride, then settle your place on the bench.

How high should the saddle go?

By the 109% rule, the seat top sits 109% of your inseam above the pedal axle; for the median body that is 25.5 inches from the crank axle at 5'2" and 34.3 inches at 6'4". The same table prints the 106% and 110.4% ends of published practice (Ferrer-Roca et al., 2012) beside the 109% of Peveler et al., 2005.

Subtracting Eunorau's 170 mm crank from the pedal-axle distance gives the crank-axle figure.

The median body's distance from the crank axle to the top of the seat at each height in the table, at 109%, 106% and 110.4% of inseam. ANSUR II women and men together; the inseam column covers the 5th to 95th percentile at each height.

The bench has one printed height, "D: Seat height 840mm/33.1in" to the ground, and Eunorau lists no adjustment range and no bracket height (the FLASH 2.0's geometry rows). With no crank-axle height to start from, no table row can be matched to the bench, so your leg and the heel check in the setup section make the call.

The bench does give you one adjustment a seatpost does not: where you sit along it. In Eunorau's side photograph of the FLASH 2.0 the crank axle sits ahead of the bench's front edge, so moving back opens the knee and moving forward bends it more.

Can I put a foot down at a stop?

From the 33.1-inch bench, 78 of 100 people at 5'10" reach the ground with both feet, 34 of 100 at 5'8" and 10 of 100 at 5'6". The barefoot inseam of each height, measured against Eunorau's printed seat height:

The median barefoot inseam at each height minus the printed 33.1-inch seat height, and how many in 100 reach the ground flat-footed while seated astride the bench. Every figure improves by the height of your soles.

Ahead of the bench, the top tube is 2.4 inches lower, and at a stop that is the easier place to stand. How many in 100 at each height clear its 30.7 inches barefoot:

How many in 100 at each height have a barefoot inseam at or above Eunorau's printed "E: Stand-Over height 780mm/30.7in". Shoes add their soles to every row.

At 5'4" and under, fewer than half of the survey clear the tube with both feet flat, and the FLASH LITE ST is the lower frame, at $1,614: a 750 W rear hub and one gear instead of a mid-drive and eight, over a 17.5-inch standover and a 31.5-inch bench, which Eunorau's launch post calls "particularly friendly for shorter riders" (our FLASH LITE ST review).

Will I feel cramped, or stretched out?

Eunorau's handlebar row reads "108mm/42.5in", with a 280 mm (11 in) reach; at 42.5 inches, or 1,080 mm, the bar sits about 9.4 inches over the 33.1-inch bench top (Eunorau's geometry rows; the row's two figures appear together in the conflicts table).

Eunorau publishes no grip position measured from the bench, and this frame's side photograph on the FLASH LITE 2.0 listing would not scale to one (Limitations), so the lean is not computed here. Your seat position does the job: slide forward and the grips come closer, slide back and your arms reach further.

How much weight goes on my hands?

The more your trunk leans past the bench, the more of it your hands hold, so sitting taller takes weight off them; with no grip position published, the load is not computed here. For a sense of scale, ten road racers on their brake hoods put 15% of their body weight through the stem (Carahalios, 2015).

When your hands tingle on a long ride, slide forward a little so your elbows bend and your chest lifts. Segment weights come from Clauser et al., 1969, and in 36 experienced riders, padded gloves reduced the pressure over the ulnar nerve by 10 to 28% (Slane et al., 2011).

How do I set the saddle when it arrives?

Seated on the bench, rest one heel on the pedal at the bottom of its stroke: a leg that is straight or nearly straight says the position is right, and a leg still clearly bent says move back.

With the ball of the foot on the pedal instead, the knee should keep 25 to 35 degrees of bend at the bottom (Peveler et al., 2007). The heel check put 70% of 19 trained riders in that range, more than either inseam formula managed (Peveler et al., 2005).

Ride from wherever the heel check puts you, and slide forward on the bench whenever you want your feet nearer the ground.

How we computed fit

Every saddle row uses the same rule, 109% of inseam from the pedal axle, with the 170 mm crank taken off for the crank-axle figure. Each stop table takes Eunorau's bench height or top-tube height away from each body's barefoot inseam.

Take the median 5'8" body, inseam 32.6 inches: 35.6 inches above the pedal axle, and 28.9 above the crank axle once the crank is subtracted; LeMond's method of 88.3% of inseam gives 28.8. That body is 0.5 inches short of flat feet on the bench and has 1.9 inches over the top tube.

Across every body in the survey, LeMond's 88.3% plus the 170 mm crank works out to 109.0% of inseam at the pedal, against the 109.2 ± 0.9% Peveler and colleagues measured in trained cyclists (Peveler et al., 2005).

The FLASH 2.0 prints the FLASH LITE 2.0's seven geometry rows, and that frame's square-on photograph, scaled by the wheelbase or by the seat height, reproduced no more than two further rows within 3.5%. So no crank-axle height, seat angle, grip position, lean or hand load is measured for this bike (Limitations).

The Mercer fit test

Every machine we review meets one family, the Mercers, and each verdict below stands on a figure Eunorau prints or on the fit model's figure for that height.

Each verdict reads the 5'2"–6'4" window, the 33.1-inch bench, the 30.7-inch top tube, the 440 lb payload, the 82–92 lb weight and the law section that follows.

Frank, Cole and Jack can mostly stay seated with both feet flat at a stop. Ruth, Maya and Dana are at heights where the survey's riders mostly clear the tube and mostly miss the bench, so they stand over the tube; a Ruth with an inseam below her row's median is better served by the FLASH LITE ST and its 17.5-inch standover. Every rider starts with the heel check in the setup section.

What the law calls a 1,000 W mid-drive with a throttle

Screened on September 30, 2026 against the e-bike definitions of all 51 jurisdictions, the FLASH 2.0's printed 1,000 W, thumb throttle and 20 mph sit inside 4: the District of Columbia, Montana, Oregon and Rhode Island. Forty-five definitions leave it out, and Alaska and Kentucky write none.

The wattage does most of the sorting. Forty-four states write a 750-watt line into the e-bike definition, and a 1,000 W motor is past it whether the statute says "less than" or "not more than". New Jersey's e-bike definition names no wattage, but its motor may help only while you pedal (P.L. 2025, c. 285), which leaves any throttle bike out.

The four definitions the FLASH 2.0 fits, each in its own words:

The definitions a 1,000 W motor with a throttle to 20 mph sits inside on September 30, 2026, each quoted from the statute linked in its row; the count holds on October 1, 2026.

The District and Montana set speed limbs and no wattage. The District's motor must be "incapable of propelling the device at a speed of more than 20 miles per hour on level ground" (D.C. Code § 50-2201.02(11A)), and Montana's may move "a rider who weighs 170 pounds no faster than 20 miles an hour" (MCA § 61-8-102(7)).

The District also asks for "a post mounted seat or saddle for each person that the device is designed and equipped to carry", and how that reads on a bench sold for two is the District's to decide (§ 50-2201.02(11A)).

Oregon's three classes name no wattage, and Rhode Island caps the motor in horsepower. Oregon's Class 2 is a bicycle that "May be propelled by its motor without a rider pedaling" and "Ceases to provide assistance once the bicycle reaches a speed of 20 miles per hour" (ORS 801.258(2)).

Rhode Island's motor is "rated not more than two (2) (S.A.E.) horsepower" (R.I. Gen. Laws § 31-1-3(g)), about 1,491 watts at NIST's 745.6999 watts to the horsepower, so the FLASH 2.0's 1,000 W is under it.

If your state is not among the four, read what its code calls a bike past its e-bike line. A machine outside the definition falls under whichever other vehicle that state's code names, and our state guide links the page for every state. In California the definition asks for "an electric motor that does not exceed 750 watts of power" (Cal. Veh. Code § 312.5(a)).

What the "Class 3" highlight means here

The FLASH 2.0's highlights read "Class 3 · Speed limited · Unlockable", while its spec rows and its product record both print "Maximum Speed 20 MPH" beside a thumb throttle. In Oregon's words a Class 3 bicycle "Provides assistance only when the rider is pedaling" and "Ceases to provide assistance when the bicycle reaches the speed of 28 miles per hour" (ORS 801.258(3)).

This review screens the FLASH 2.0 as it ships, at the 20 mph its spec rows print, with the throttle, and describes no change to any setting. Read your state's definition before you change one.

Charging and battery care

The FLASH 2.0 ships with a "US standard 4.0 A smart charger", and a 16 Ah pack at 4 A takes about 4 hours of full current before the charger slows near the top. A 20-mile ride at 15 mph on the throttle draws about 354 Wh from the cells (the range section), under half the standard pack.

Carry all three packs and you hold 2,808 Wh (Eunorau's battery row), so the second and third packs are for your long days, and the daily ride runs on the first.

Recharge with 10 to 15% still in the pack, Eunorau's general FAQ advises, and keep a pack you are laying up for more than two weeks "in a cool, dry place with a 70%-80% charge remaining". By Eunorau's own figures a pack should "typically last 5-6 years" and "still deliver more than 80% of their original capacity after 500 charge cycles".

Where Eunorau prints a figure two ways

The FLASH 2.0 is described on its product page, in its product record, in the listings for its extra packs, on TruckRun's page for the motor and in Eunorau's FAQs. Where two read differently, the last column names the figure this review uses.

The page and record read on September 26 and September 30, 2026, unchanged between the two; the pack listings, the FAQs, TruckRun's page and the warranty policy on September 30.

Has it been recalled?

No federal recall names Eunorau or the FLASH 2.0. On September 30, 2026 we searched the CPSC's recall database for "Eunorau" and for "FLASH 2.0" in the recall title, description and product name fields; each field returned records for a control query in the same run, and none returned a recall for either name. Across the 51 recalls whose titles name an electric bicycle, an e-bike or an electric scooter, Eunorau appears in none.

We also read all 373 rows of the CPSC's product safety warning listing that day: two matched the control brand, and none matched Eunorau or the FLASH 2.0.

Is it UL certified?

Eunorau's FLASH 2.0 page lists "UL CERTIFIED Yes" among its highlights, and TruckRun names a UL certificate among the M09's certifications. For a whole e-bike the standard is UL 2849, which covers the electrical system, and for a pack UL 2271. If your landlord, building or insurer wants the certificate, note it on your order and we will ask Eunorau for it.

Warranty, and who handles a claim

Read on September 30, 2026, Eunorau's warranty policy sets a term for each part:

The policy is issued by Eunorau Bikes, "a Nevada corporation", and covers bikes bought in the US from August 1, 2023 against manufacturing defects in the parts it fitted (the policy). It asks three things of you: "You are the original purchaser", "Product Registration right after the purchase", and an "E-bike check-up by a Eunorau specialist or dealer after the first year of use".

Labor and wear parts fall outside it, and our Eunorau brand profile sets these terms beside the rest of the range. The courier's brake-line failure went through Eunorau's warranty without a fuss (the ride).

Buy your FLASH 2.0 from us and a warranty claim is ours to carry. Send a photo and a line on what failed, and we work with Eunorau until the part reaches your door.

Buying it from us

The value case in numbers. On September 30, 2026 our listing split the $2,499 into 12 payments of $225.56, 6 of $434.91 or 3 of $853.91, all at 15% APR.*

*Rates from 0-36% APR. Payment options through Shop Pay Installments are subject to an eligibility check and are provided by these lending partners: affirm.com/lenders. Options depend on your purchase amount, and a down payment may be required. State notices to consumers: affirm.com/licenses.

Weighing the FLASH 2.0 against another FLASH? Send your height, inseam, state, your usual load and the steepest hill on your route to support@redtailebikes.com, and we will tell you plainly which one fits. We do not stock the extra FLASH packs, the rack or the fender, so ask us before you order them and we will say where Eunorau sells each one.

The honest ledger

Green flags

• A 1,000 W TruckRun mid-drive rated at 220 N·m, working through eight gears: 17.1 mph up an 8% street on the throttle with 180 lb aboard (the climb table).
• An 832 Wh pack and two more bays: about 57 miles at 12 mph on the throttle for a 180 lb rider, and 2,808 Wh with all three fitted (the range tables).
• Full suspension: an 80 mm EXSHO STRONG-DH fork with lockout and a 290 mm coil shock rated to 1,000 lb (the parts section).
• 4-piston hydraulic discs on 180 mm rotors at both ends, and a motor cutoff at each lever (the parts section).
• 440 lb for you, a passenger and your cargo on a bench Eunorau sells for two (the payload section).
• Ridden in mud and rain: the torque sensor and the shift pause work as published, and the frame stayed quiet off pavement (the ride).
• The same $2,499 Eunorau charged on September 30, 2026, for either color (buying from us).

Red flags: where it is the wrong bike, and what to do

• Your riding is stop-and-go traffic: a mid-drive wants a shift at every light, and the FLASH LITE 2.0 is this frame on one rear hub that needs none, for $1,614 (our FLASH LITE 2.0 review).
• You are under about 5'5" and want both feet flat at every light: the FLASH LITE ST steps through at 17.5 inches (our FLASH LITE ST review); or find your height in the stop tables.
• Your state's definition names a wattage: the FLASH LITE 2.0's 750 W hub, throttle and 20 mph fit 28 of 51 definitions on September 30, 2026 and 29 from October 1 (its law section); where the word is "less than" 750 watts, the META20 folds on 500 W for $1,699 (our META20 review).
• Mud is your regular ground: plan a knobbier tire before the first wet ride, since the stock CST slid on our plowed field (the ride).
• You would rather twist than press a thumb: the torque-sensor assist does the throttle's work while you pedal (the ride); tell us before ordering and we will talk you through the controls.
• A small child rides with you: Eunorau's long-tail MAX-CARGO is built for that; our MAX-CARGO review covers its child seats and each state's rules on carrying children.

Who should buy it

Buy the FLASH 2.0 if you want a moped-style bike that climbs through gears, full suspension for broken ground, a throttle to 20 mph, room for 440 lb and two more packs, and a state whose definition takes in a 1,000 W motor, for $2,124.

Choose the FLASH LITE 2.0 instead if you ride in traffic or on the flat, the FLASH LITE ST if your inseam falls short of the 30.7-inch tube, and the FLASH AWD 1.0 if you want both wheels driven for $400 less.

Pass on the FLASH 2.0 if your state names a wattage and you want to ride as an e-bike there: our META20 review covers a 500 W bike, and our FLASH LITE 2.0 review a 750 W one.

Before you buy: the checklist

Eight checks: four that confirm the FLASH 2.0 is your bike, four that get the order and the first week right.

• ☐ Look up your state's e-bike definition and see whether it names a wattage; our state guide links every state's code.
• ☐ Measure your inseam in socks and find your rows in the stop tables: both feet flat astride the 33.1-inch bench, or standing over the 30.7-inch tube.
• ☐ Add up rider, passenger and cargo against the 440 lb; the bike's 82 to 92 lb is not part of it.
• ☐ Plan where a bike of up to 92 lb and 68.5 inches will live, with a ramp for any steps.
• ☐ Price your longest ride at 15 mph on the throttle: the standard pack plans 40 miles for a 180 lb rider on level ground.
• ☐ From empty, the 4.0 A charger needs about 4 hours of full current, so charge on arrival before a long first ride.
• ☐ On the first ride, practice shifting down before a climb, and learn the throttle seated on flat ground.
• ☐ Inspect the box while the driver waits, and send us photos within 48 hours of any damage.

Limitations of this review

Twenty-one limits on this review, numbered, each tied to the section it qualifies.

1. The FLASH 2.0's specifications are Eunorau's figures from its page, record, FAQs, pack and accessory listings, recomputed wherever arithmetic enters. The ride, the range and fit models, the jurisdiction screen and our store terms are ours, each explained below.
2. The ride was not logged: no speed, distance, gradient, temperature or rider weight was recorded, so the ride section reports what the rider observed, and every figure on the page comes from the model or from Eunorau.
3. Every range row is one steady speed on one grade in still air. Starts, stops and headwinds cost more, and town rides stop often; a tailwind costs less.
4. Eunorau prints the class label, the drivetrain's teeth, which bay holds which pack, the handlebar height and the warranty more than one way, and TruckRun prints the motor's torque by version (the conflicts table); the review uses the figure named there.
5. The FLASH 2.0's page and record print a 4.0 A charger and no charge time, so the charging section gives our arithmetic from the 16 Ah pack and the 4.0 A charger, leaving out the charger's slowdown near full.
6. The screen sets the printed 1,000 W, the throttle and the 20 mph beside each definition as our rule table and the statutes stood on September 30, 2026. It reads the motor, speed and throttle limbs, leaves age, helmet, seat and passenger rules to each state, and is not legal advice.
7. Rhode Island's horsepower is converted at NIST's mechanical horsepower of 745.6999 watts; the statute names the S.A.E. rating and prints no conversion of its own.
8. The screen reads the bike at the spec rows' 20 mph with the throttle. The "Class 3" label in the highlights is not screened.
9. The recall screens ran on September 30, 2026 on the three CPSC database fields named in the recalls section, each shown working by a control query. A search of recall titles is a floor, not the whole database, since a recall titled by a brand name alone escapes it; the warning listing's 373 rows were read the same day.
10. Our price, orderability and Shop Pay terms come from our own listing; the payments are its plan table for $2,499 at 15% APR, read September 30, 2026.
11. The motor model is a labeled estimate built on TruckRun's rated point. TruckRun prints the M09's 1,000 W at 135 rpm and no no-load speed, so the model borrows the no-load ratio of Bafang's M615 at 1,000 W and brackets it with two other published ratios (the formula).
12. TruckRun's "≥80" efficiency is read as the motor's best efficiency, not its rated one, since at the rated speed the back-voltage allows no more than 78%; the 78% ceiling is printed as a bracket.
13. Eunorau names no cog sizes, so the model uses Shimano's CS-HG31-8 11-32, bracketed by the same cassette's 11-30 and 11-34 versions, which move the 12 mph throttle ride by a tenth of a mile.
14. No drum or road measurement of the CST 20 × 4.0 was found, so the model uses the median of twelve fat-bike tires on Bicycle Rolling Resistance's drum, bracketed by the slowest and the fastest of the twelve.
15. The model's wheel is the nominal 20 × 4.0 diameter, 23.98 inches, and its drag area the upright cruiser figure of 37 everyday riders; a loaded fat tire rolls slightly smaller, and no field measurement of a moped-style bike with a bench was found.
16. The cold rows use McMaster's measured LG HG2 cell as the central line, bracketed by Samsung's 35E data sheet and Casado et al., 2025; the record names "LG+" cells without naming the cell model.
17. The model carries the 82 lb end of Eunorau's 82 to 92 lb, and the two-pack column leaves out the 21 Ah pack's 13.9 lb from Eunorau's listing; the weight table prices the difference as rider weight.
18. The fit tables use the bodies of US Army personnel. ANSUR II measured 6,068 soldiers aged 17 to 58 in 2010 to 2012; how inseam varies at a given height should carry over to civilians, while the exact spread may not.
19. The fit is the formula and Eunorau's two printed heights. The FLASH 2.0's seven geometry rows equal the FLASH LITE 2.0's, whose square-on studio photograph reproduced at most two other rows within 3.5%, so no crank-axle height, seat angle, grip position, lean or hand load is measured, and Eunorau's rows print none of them.
20. Eunorau prints one seat height, 33.1 inches, and no adjustment range for the bench, so the fit section reads the bench at that height; treat the saddle formula as a first setting, since among 19 trained cyclists the inseam formulas put 55 to 65% inside the 25 to 35 degree knee range and the heel check 70% (Peveler et al., 2005).
21. The payload section quotes California's statute as one example of a passenger rule, and the outdoor photograph is Eunorau's, undated and unplaced. Expiry: re-verify if Eunorau changes the motor, a pack, the speed, the payload, the rider window, the seat height, the geometry or the pack listings, if our price moves, or if any state's definition changes.

The source register

What the review rests on, by tier and by use: Eunorau's page, record, FAQs, listings and policy, TruckRun's motor page, the statutes, the CPSC's lists, the published measurements under both models, our ride and our own datasets.

Frequently asked questions

Is the Eunorau FLASH 2.0 worth it?

For $2,499 you get a 1,000 W TruckRun mid-drive through eight Shimano gears, full suspension, hydraulic brakes, a 440 lb rating and two spare battery bays; on the throttle a 180 lb rider covers about 57 miles at 12 mph and climbs an 8% grade at 17.1 mph. If you mostly ride flat streets in traffic, the one-hub FLASH LITE 2.0 costs $600 less (the family table).

How fast does the Eunorau FLASH 2.0 go?

Both the spec rows and the product record print a maximum speed of 20 mph. In the model your throttle carries a 180 lb rider on the flat to that 20 mph, holds 17.1 mph up an 8% grade and 13.2 mph up 12% (the climb table); the "Class 3" label in the highlights sits beside that 20 mph in the conflicts table.

Is a 1000 W e-bike legal?

It depends on your state's definition: on September 30, 2026 the FLASH 2.0's printed 1,000 W, throttle and 20 mph fit 4 of 51, the District of Columbia, Montana, Oregon and Rhode Island. Forty-four states write a 750-watt line into the definition, New Jersey rules out the throttle, and Alaska and Kentucky have no definition; the law section quotes the four that fit.

Is a 1000 W e-bike legal in California?

If you ride in California, its definition asks for "an electric motor that does not exceed 750 watts of power", and a 1,000 W motor is over that line. Cal. Veh. Code § 312.5(a) is the definition, and a bike outside it falls under whichever other vehicle California's code names (the law section).

What size rider does the Eunorau FLASH 2.0 fit?

Eunorau fits it to riders from 5'2" to 6'4", and your inseam decides how you stop: at 5'4" 43 of 100 people in the Army's survey clear its 30.7-inch top tube barefoot, and at 5'10" 78 of 100 reach the ground from the 33.1-inch bench. If your row reads short, the FLASH LITE ST's 17.5-inch standover is the lower frame (the stop tables).

How does a mid-drive e-bike work?

The motor turns the chainring at the cranks, so its power reaches your back wheel through the gears, the way your legs' does. On the FLASH 2.0 that means a 44-tooth chainring and eight cogs, and the cog you pick sets the motor's speed: up an 8% grade at 8 mph the biggest cog costs 74 Wh a mile and the smallest 221 (the gear section).

Is a mid-drive better than a hub motor?

On the same frame and pack, the model gives the mid-drive the hills and the hub a few more flat miles. Up an 8% grade with 180 lb aboard, the FLASH 2.0 holds 17.1 mph on the throttle and the one-hub FLASH LITE 2.0 13.9; at 12 mph on the flat, the hub covers 61 miles to the mid-drive's 57 (the drive section).

Are mid-drive e-bikes better for hills?

Against one hub on the same frame, yes in the model, and the gears are why. The FLASH 2.0 holds 17.1 mph up an 8% grade on the throttle with 180 lb aboard, the one-hub FLASH LITE 2.0 13.9, and in the 32-tooth cog an 8% climb at 8 mph gives you 11 miles from the pack against 4 in the 11-tooth (the gear tables).

Do mid-drive e-bikes have a throttle?

This one does: Eunorau fits a thumb throttle, which moves the bike with no pedaling. Because the motor drives the chainring, the throttle works through your gears too, so on a climb you shift down as you would when pedaling (the drive section).

How far can the FLASH 2.0 go on one charge?

On the throttle, about 57 miles at 12 mph, 47 at 15 and 33 at 20 for a 180 lb rider on flat pavement, from the standard 832 Wh pack. Keep Eunorau's 15% in reserve and plan on 49 at 12 mph; with the 21 Ah second pack fitted, the 12 mph plan grows to 112 miles (the speed table).

Can the FLASH 2.0 really go 220 miles?

With all three packs, 2,808 Wh, the model reaches Eunorau's 220 miles at a steady 9.9 mph on the throttle, or 15.7 mph if you pedal lightly, for a 180 lb rider on the flat. Eunorau's page ties the figure to "pedal assist 1" with all three batteries on board, and the two extra packs cost $1,298 (the maker's figures, as rides).

What e-bike has the longest range?

Range is the energy you carry divided by what each mile costs, so it depends on the bike, the speed and you. The FLASH 2.0 carries up to 2,808 Wh across three packs, and on the standard pack alone, pedaling lightly at 15 mph, the model gives a 180 lb rider 72 miles (the speed section).

Are full suspension e-bikes worth it?

They earn their place on broken pavement, dirt and ruts, where the rear wheel takes hits the frame would otherwise pass to you. The FLASH 2.0 is the only one of our four FLASH models with a rear shock, a 290 mm coil rated to 1,000 lb, and on our field ride both ends could be felt working (the ride).

How much does the Eunorau FLASH 2.0 weigh?

Eunorau lists 82 to 92 lb, before any extra pack; the 21 Ah adds 13.9 lb and the 17 Ah 10.5 lb. Your 440 lb payload is on top of that, and the weight table prices your range from 130 lb to 440 (the weight table).

Can two people ride the FLASH 2.0?

Eunorau sells the bench for "a single rider" or a rider with "a companion", within a 440 lb payload, and our rider judged it long enough for two. Whether a passenger may ride is your state's rule; California's § 21204(b), for one, requires "a separate seat attached thereto", and the $59 FLASH rack is for cargo only (the payload section).

What batteries does the FLASH 2.0 take, and what do they cost?

It ships with a 52V 16Ah pack, 832 Wh, and takes two more: Eunorau lists a 52V 21Ah at $699 and a 52V 17Ah at $599. With all three you carry 2,808 Wh. We do not stock the two extra packs, so ask us before ordering and we will say where Eunorau sells each (the frame section).

What warranty does Eunorau give on the FLASH 2.0?

Eunorau's policy gives the frame 10 years and the battery, motor and electrical parts 24 months, for the original purchaser who registers the bike. Buy it from us and we run any claim; the courier's front brake line was replaced under warranty without a fight (the warranty section).

Are Eunorau bikes good?

Eunorau names its parts and publishes its terms, so you can check each one: on the FLASH 2.0, a TruckRun motor, an EXSHO STRONG-DH fork, Shimano gears, CST tires, 4-piston hydraulic brakes, a 10-year frame warranty and a "UL CERTIFIED Yes" mark. Our Eunorau brand profile covers the whole range.

Where are Eunorau bikes made?

Eunorau's FAQ says its bikes are "designed in the U.S. and manufactured in Shanghai", with a team "overseeing quality control and inspecting every bike before it is shipped to our customers".

Are moped-style e-bikes legal?

Looks do not decide it: a moped-style bike rides under your state's e-bike rules only when it fits your state's definition. That turns on the motor, the speed and how the assist works, and at a printed 1,000 W the FLASH 2.0 fits 4 of 51 definitions on September 30, 2026 (the law section).

The bottom line

The Eunorau FLASH 2.0 is a $2,499 moped-style step-over with a 1,000 W TruckRun mid-drive, eight Shimano gears, an 80 mm fork and a coil rear shock, hydraulic brakes, a 440 lb rating and an 832 Wh pack with bays for two more: inside 4 of 51 jurisdictions' e-bike definitions as printed, on September 30, 2026.

On the throttle a 180 lb rider covers about 57 miles at 12 mph and 33 at 20, holds 17.1 mph up an 8% grade, and with the full 440 lb aboard still gets 34 miles at 15 mph.

Buy it for hills, rough ground, a passenger behind you and a range you can grow with more packs, for riders from 5'2" to 6'4", the window Eunorau prints. If you ride mostly in traffic, read our FLASH LITE 2.0 review first.

References

Every document behind the figures and rules on this page, numbered in the order the page first leans on it, with its publisher, title, the part cited and the date we read it.

1. Eunorau. FLASH 2.0 — product page and product record: highlights, specification and geometry rows, the feature copy, the compatible-accessory prices and the studio and outdoor gallery. eunorau-ebike.com/products/flash-2; product record flash-2.json. Retrieved September 26, 2026 and re-read September 30, 2026 with no change to any row; deposit copies archived.
2. Eunorau. FLASH LITE 2.0 product page and record: the same frame's rows ("Hard Tail"; "Front shock, no rear"), and its product FAQ's triage between the FLASH LITE 2.0, the FLASH AWD and the FLASH 2.0. eunorau-ebike.com/products/flash-lite-2-0. Retrieved September 26, 2026 and re-read September 30, 2026 with no change; deposit copies archived.
3. Eunorau. FLASH LITE ST product page and record: the step-through's frame, 60 mm fork, standover and rider window. eunorau-ebike.com/products/flash-lite-st. Retrieved September 26, 2026 and re-read September 30, 2026 with no change; deposit copies archived.
4. Redtail Electric Bikes USA. "Eunorau FLASH 2.0 Review: 1000W Mid-Drive Fat Tire eBike in Fall Mud", 6:14, our own footage, published September 17, 2026. youtube.com. With the rider's account of September 19, 2026, archived.
5. Redtail Electric Bikes USA. "The Motor Doesn't Turn the Wheel | Eunorau FLASH 2.0 in the Rain", 2:41, our own footage, published September 17, 2026. youtube.com.
6. Eunorau. EUNORAU Rear Rack for FLASH Ebikes ($59): "Heavy-duty build securely holds up to 25 kg (55 lbs)"; "Cargo Only: Strictly for gear. NOT recommended for passengers or sitting."; "No Child Seats". eunorau-ebike.com/products. Retrieved September 30, 2026; deposit copy archived.
7. TruckRun. M09 Mid Drive Motor: "available in three versions with 750/1000/1200W, and a maximum torque of 150/200/220N.m", the parameter table (rated voltage, rated power, rated speed, efficiency) and the certification list. truckrun-e.com. Retrieved September 30, 2026; deposit copy archived, with TruckRun's product manual of August 16, 2024.
8. Eunorau. EUNORAU 52V21Ah Secondary Battery for FLASH Ebike ($699; "Weight 13.9 lbs"; "Down tube battery type") and EUNORAU 52V17Ah Third Battery for FLASH Ebike ($599; "Weight 10.5 lbs"; "Top tube battery type"), product pages and records. 21 Ah; 17 Ah. Retrieved September 30, 2026; deposit copies archived.
9. Eunorau. FLASH AWD 1.0 product page and record: the dual-hub sibling's rows ("Hard Tail"; "Front shock, no rear"). eunorau-ebike.com/products/flash-awd-1-0. Retrieved September 26, 2026 and re-read September 30, 2026 with no change; deposit copies archived.
10. Eunorau. Hunting Ebike Trailer Guide: How Much Gear Can You Tow (blog post, May 31, 2026): "Payload covers the rider and anything carried on the bike itself." eunorau-ebike.com/blogs/news. Retrieved September 24, 2026; deposit copy archived.
11. California Legislative Information. Cal. Veh. Code § 21204, subsection (b). leginfo.legislature.ca.gov. Read September 30, 2026 through a text proxy of the code page; deposit copy archived. Amended by Stats. 2009, Ch. 594 (SB 527), effective January 1, 2010.
12. California Legislative Information. Cal. Veh. Code §§ 21212 and 21213, subsections (a): the helmet rule for riders under 18 and the Class 3 age limit. § 21212; § 21213. Read September 30, 2026 through a text proxy of the code pages; deposit copies archived. § 21213 added by Stats. 2015, Ch. 568 (AB 1096), effective January 1, 2016.
13. Council of the District of Columbia. D.C. Code § 50-2201.02(11A), the motorized-bicycle definition: the seat, wheel, pedal and 20 mph motor limbs. code.dccouncil.gov. Read for the census of September 24, 2026; deposit copy archived.
14. Montana Legislature. MCA § 61-8-102(7), the electrically assisted bicycle: a motor moving "a rider who weighs 170 pounds no faster than 20 miles an hour on a paved, level surface". mca.legmt.gov. All Title 61 sections read September 23, 2026; deposit archived.
15. Oregon Legislature. ORS 801.258, the three classes of electric assisted bicycle and its definition "equipped with an electric motor", as amended by 2024 c.12 § 1. oregonlegislature.gov. Read for the census of September 24, 2026; deposit copy archived.
16. Rhode Island General Assembly. R.I. Gen. Laws § 31-1-3(g), the electric motorized bicycle: a motor "rated not more than two (2) (S.A.E.) horsepower". webserver.rilegislature.gov. Read for the census of September 24, 2026; deposit copy archived.
17. National Institute of Standards and Technology. NIST Guide to the SI, Appendix B.9 (SP 811): "horsepower (550 ft · lbf/s)" to watts, 7.456 999 E+02. nist.gov. Retrieved September 30, 2026; deposit copy archived.
18. California Legislative Information. Cal. Veh. Code § 312.5, subsection (a): the definition's "an electric motor that does not exceed 750 watts of power". leginfo.legislature.ca.gov. Retrieved September 26, 2026.
19. The legislatures of the 44 states that write a 750-watt line into the electric-bicycle definition. Each definition, at the section recorded in our rule table, with its own boundary word for the motor. Read for the boundary-word census of September 24, 2026 and re-screened September 30, 2026.
20. New Jersey Legislature. P.L. 2025, c. 285, amending R.S. 39:1-1: the electric bicycle's motor assists only while the rider pedals, and the definition names no wattage. pub.njleg.gov. Read for the census of September 24, 2026; enacted text archived.
21. Alaska State Legislature. AS 28.90.990(a)(20)-(22). akleg.gov. Retrieved September 26, 2026. No electric-bicycle definition.
22. Kentucky Legislature. KRS 189.010. apps.legislature.ky.gov. Retrieved September 26, 2026. No electric-bicycle definition.
23. Redtail eBikes editorial desk. The 51-jurisdiction rule table, its boundary-word census, and the FLASH 2.0 screen. Every US state and DC, each row carrying its statutory citation and each wattage read with the statute's own word; screened September 30, 2026 on the published 1,000 W, throttle and 20 mph: inside 4 (the District of Columbia, Montana, Oregon, Rhode Island), outside 45, no definition in Alaska and Kentucky; the count is the same from October 1, 2026. First-party dataset.
24. Eunorau. EUNORAU EBIKES FAQ: battery life ("5-6 years"; "more than 80% of their original capacity after 500 charge cycles"), the 10-15% recharging and 70%-80% storage advice, and where the bikes are made. eunorau-ebike.com/pages/faqs. Retrieved September 26 and 30, 2026; deposit copies archived.
25. U.S. Consumer Product Safety Commission. SaferProducts recall database. saferproducts.gov/RestWebServices/Recall. Screened September 30, 2026 for "Eunorau" and "FLASH 2.0" on the RecallTitle, RecallDescription and ProductName fields, each proved live by a control query, and for "Eunorau" across the 51 recalls whose titles carry one of eight electric-bicycle, e-bike or electric-scooter terms, unioned; screens archived.
26. U.S. Consumer Product Safety Commission. Product safety warning listing (complete CSV). cpsc.gov. Read September 30, 2026: 373 warnings, 2 naming the control brand, none naming Eunorau or the FLASH 2.0; deposit copy and screen archived.
27. UL Standards & Engagement (standards body; context only). UL 2849 and UL 2271. Retrieved August 29, 2026.
28. Eunorau Bikes. 24-Month+ Limited Warranty: coverage periods, requirements, exclusions and the issuing entity. eunorau-ebike.com/pages/warranty. Retrieved September 26 and 30, 2026; deposit copies archived.
29. Redtail eBikes. FLASH 2.0 store record (redtailebikes.com/products/eunorau-flash-2): the two colors, price, orderability and the Shop Pay plan table; the FLASH family, META20 and MAX-CARGO prices; our Eunorau parts shelf; and our shipping policy. Read September 30, 2026.
30. Affirm. Lending partners. affirm.com/lenders. The lenders behind Shop Pay's installment plans, named in Shopify's installment terms.
31. Bafang. Workbook OEM 2021, MOTORS table, M615 (MM G320.750.C / MM G320.1000.C) and M620 (MM G510.750.C / MM G510.1000.C) columns: rated voltage, n0, rated power and nT. bafang-e.com. Retrieved September 23 and September 26, 2026; deposit copy archived.
32. Shimano. Exploded view EV-CS-HG31-8-3234A, CS-HG31-8 cassette sprocket: the 11-32, 11-30 and 11-34 teeth combinations. si.shimano.com. Read September 30, 2026 through a text proxy of the PDF; deposit copy archived.
33. Martin, J. C., Milliken, D. L., Cobb, J. E., McFadden, K. L. and Coggan, A. R. Validation of a Mathematical Model for Road Cycling Power. Journal of Applied Biomechanics 14(3):276–291 (1998), Eq. 14 and Appendix I; doi 10.1123/jab.14.3.276. collections.lib.utah.edu. Retrieved September 23, 2026.
34. Tengattini, S. and Bigazzi, A. Y. Physical characteristics and resistance parameters of typical urban cyclists. Journal of Sports Sciences 36(20):2383–2391 (2018), Table 4 (drag area by bicycle type); doi 10.1080/02640414.2018.1458587. civil-reactlab.sites.olt.ubc.ca. Retrieved September 23, 2026.
35. Arango, I., Lopez, C. and Ceren, A. Improving the Autonomy of a Mid-Drive Motor Electric Bicycle Based on System Efficiency Maps and Its Performance. World Electric Vehicle Journal 12(2):59 (2021), the measured efficiency map and Eq. (40); doi 10.3390/wevj12020059. mdpi-res.com. Retrieved September 23, 2026.
36. Hansen, E. A. et al. Freely chosen cadence during ergometer cycling is dependent on pedalling history. European Journal of Applied Physiology 121(11):3041–3049 (2021), Results; doi 10.1007/s00421-021-04770-w. pubmed.ncbi.nlm.nih.gov. Retrieved September 26, 2026.
37. Marsh, A. P. and Martin, P. E. Perceived exertion and the preferred cycling cadence. Medicine and Science in Sports and Exercise 30(6):942–948 (1998), Results; doi 10.1097/00005768-199806000-00025. pubmed.ncbi.nlm.nih.gov. Retrieved September 26, 2026.
38. Bicycle Rolling Resistance. Kenda Juggernaut Pro (fat-bike drum test, 12 psi, and the site's list of twelve current fat-bike tires). bicyclerollingresistance.com. Retrieved September 25, 2026.
39. Kollmeyer, P. et al. LG 18650HG2 Li-ion Battery Data. Mendeley Data v2, McMaster University; doi 10.17632/b5mj79w5w9.2 (0.5C discharge files, recomputed). doi.org. Retrieved September 23, 2026.
40. Samsung SDI. Specification of Product INR18650-35E, Ver. 1.1 (July 9, 2015), § 7.5 Temperature Dependence of Discharge Capacity. enerpower.de. Retrieved September 23, 2026.
41. Casado, S. et al. Evaluation of commercial Li-Ion 18650 battery cells for deep space applications. Journal of Power Sources 638:236552 (2025), Table 3; doi 10.1016/j.jpowsour.2025.236552. doi.org. Retrieved September 23, 2026.
42. NOAA, NASA and US Air Force. U.S. Standard Atmosphere, 1976 (NOAA-S/T 76-1562), sea-level pressure and the composition of dry air. ntrs.nasa.gov. Retrieved September 23, 2026.
43. Rothhämel, M. On rolling resistance of bicycle tyres with ambient temperature in focus. International Journal of Vehicle Systems Modelling and Testing 17:67–80 (2023), Tables 1 and 4; doi 10.1504/IJVSMT.2023.132317. inderscience.com. Retrieved September 23, 2026.
44. Sheldon Brown and John Allen (Harris Cyclery). Tire Sizing Systems, the ISO/E.T.R.T.O. chart: "20 x 1.5-20 x 2.125 | 406 mm". sheldonbrown.com. Retrieved September 28, 2026; deposit copy archived.
45. U.S. Army Natick Soldier Research, Development and Engineering Center. 2012 Anthropometric Survey of U.S. Army Personnel (ANSUR II), public data release (4,082 men, 1,986 women). army.mil. Retrieved September 25, 2026.
46. Peveler, W., Bishop, P., Smith, J., Richardson, M. and Whitehorn, E. Comparing Methods for Setting Saddle Height in Trained Cyclists. Journal of Exercise Physiology Online 8(1):51–55 (2005). asep.org. Retrieved September 25, 2026.
47. Ferrer-Roca, V., Roig, A., Galilea, P. and García-López, J. Influence of saddle height on lower limb kinematics in well-trained cyclists: static vs. dynamic evaluation in bike fitting. Journal of Strength and Conditioning Research 26(11):3025–3029 (2012). pubmed.ncbi.nlm.nih.gov. Retrieved September 25, 2026.
48. Carahalios, A. An Analysis of the Bicycle-Rider Interface Forces in Stationary Road Cycling. MS thesis, University of Colorado (2015). scholar.colorado.edu. Retrieved September 25, 2026.
49. Clauser, C. E., McConville, J. T. and Young, J. W. Weight, Volume, and Center of Mass of Segments of the Human Body, AMRL-TR-69-70 (1969). ntrs.nasa.gov. Retrieved September 25, 2026.
50. Slane, J., Timmerman, M., Ploeg, H. L. and Thelen, D. G. The influence of glove and hand position on pressure over the ulnar nerve during cycling. Clinical Biomechanics 26(6):642–648 (2011). pubmed.ncbi.nlm.nih.gov. Retrieved September 25, 2026.
51. Peveler, W. W., Pounders, J. D. and Bishop, P. A. Effects of saddle height on anaerobic power production in cycling. Journal of Strength and Conditioning Research 21(4):1023–1027 (2007). pubmed.ncbi.nlm.nih.gov. Retrieved September 25, 2026.
52. Redtail eBikes editorial desk. FLASH 2.0 range model. The computation set out in the range section of this review: Martin et al.'s power model with a motor curve built on TruckRun's rated point for the M09 at 1,000 W, the no-load ratio of Bafang's M615 and Eunorau's 220 N·m ceiling, efficiency fitted to Arango, Lopez and Ceren's measured mid-drive map, driving a 44T chainring through Shimano's 11-32 eight-speed cogs on a 23.98-inch 20 × 4.0 wheel with the median of twelve fat tires; Eunorau's 65, 135 and 220 miles mapped to rides; run September 30, 2026. First-party computation; every input and its source in its inputs table.
53. Redtail eBikes editorial desk. FLASH 2.0 fit model. Every ANSUR II body through the saddle formula at Eunorau's 170 mm crank, and each body's barefoot inseam against Eunorau's printed 33.1-inch seat height and 30.7-inch standover; the same seven geometry rows as the FLASH LITE 2.0, whose square-on photograph reproduced at most two other rows within 3.5% and was not used for any measurement; September 30, 2026. First-party computation; every input and its source in its inputs table.