Eunorau SPECTER-ST 2.0 Review 2026: Low Standover

1000 W · 160 N·m · 1,560 Wh in the box · 19.3 in standover · 300 lb payload · 88 lb bike · $2,999 · verified September 26, 2026

Quick Answer — The Eunorau SPECTER-ST 2.0 is a $2,999 full-suspension step-through with a 1000 W Bafang M620 mid-drive and a 19.3-inch standover. A 180 lb rider gets about 48 miles at 15 mph on the throttle on flat pavement, and about 90 with the second 48V 15Ah pack that ships free with it as of September 26, 2026.

The motor is rated 1000 W, above the 750 watts California's statute allows an electric bicycle, so the class section is worth reading before you order.

What's on this page

The review runs in twenty sections, from who the SPECTER-ST 2.0 suits, through the computed range and fit and the class statute, to the checklist and the bottom line; each link jumps to its section.

• Who the SPECTER-ST 2.0 is for
• How we verified this review
• Eunorau SPECTER-ST 2.0 specifications
• Payload, rider height and top speed
• What a 160 N·m mid-drive actually buys
• How far it goes, gear by gear
• Will it fit you?
• Full suspension: 140mm up front, a DNM shock behind
• The "Class 3" label and the statute
• Is the battery UL certified?
• The Mercer fit test
• Warranty
• Ordering, shipping and support
• 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 SPECTER-ST 2.0 is for

The frame is the point: a 19.3-inch standover on a bike with suspension at both ends.

Someone who wants to ride trails, gravel and hills, and who wants to get on the bike by stepping through it instead of swinging a leg over a top tube.

That combination is scarce. We screened our own live catalog (211 active listings tagged e-bike on September 25, 2026), and exactly two machines pair a step-through frame with full suspension and a mid-drive; this is the only one of them built as an eMTB. It is a 1000 W Bafang mid-drive with 160 N·m of torque on a frame with a 19.3-inch standover and suspension at both ends.

Skip it if lifting is part of your day: at a published 88 lb, this bike lives at ground level.

Both of the things this review keeps returning to are in this one frame: the front triangle drops away where a top tube would be, and a shock sits tucked behind the seat tube.

How we verified this review

Every bike specification on this page is Eunorau's own, verified on September 24, 25 and 26, 2026 against its product page and its product record, and recomputed wherever arithmetic is involved; the eleven images the page links were opened on August 29, 2026. Every legal statement links the provision it rests on and quotes the definition it turns on. Where a fact has one publisher, such as Eunorau's specification or a statute, that publisher is cited alone.

Each section states its own method: the range and fit sections close on their formulas and every input, and the recall screen of September 24, 2026, the catalog screen and our price and payment terms are items 9, 11 and 12 of the Limitations.

Redtail sells this machine, and the honest ledger carries what does not flatter it. The author is Milad Ghobadibeygvand, BScN (Western University, 2014). Corrections go to corrections@redtailebikes.com.

Eunorau SPECTER-ST 2.0 specifications

Every figure below is from Eunorau's specification, Components list and geometry table, retrieved August 29, September 24 and September 25, 2026.

The Bafang DPC18 from the table's Display row. The readout is km/h in Eunorau's own photograph.

Payload, rider height and top speed

Eunorau's specification lists the three figures a buyer asks for first. Under "Electronics" it gives a 300 lb total payload, a 5'3"–6'4" rider range and a 28 mph maximum ("Maximum Speed 28MPH / 45KMH"), beside the motor, the battery and a 5 – 8 hour charge on the 2.0 A charger.

The parts sit in its "Components" list: 27.5" × 3.0" tires, an SRAM NX 1×11 drivetrain, 180mm hydraulic rotors, a 140mm fork and a DNM rear shock.

Read the 300 lb as rider and cargo combined. Eunorau's own definition is that "Payload covers the rider and anything carried on the bike itself", so the bike's 88 lb sits outside it. The rear rack is optional on Eunorau's listing, so ask us before you plan a load around one.

Read the rider range beside the 19.3-inch standover and the fit tables, and the 28 mph maximum beside the class section.

Four pistons on a 180mm rotor, per Eunorau's page.

What a 160 N·m mid-drive actually buys

A mid-drive puts the motor at the cranks and sends its power through the chain and cassette, so the motor gets the same gear range you do. A hub motor is stuck in one effective gear all the time.

On a hill, that is the whole argument. Drop into the 42-tooth sprocket and the motor's torque is multiplied by the same ratio your legs get. The published figure here is 160 N·m, from a Bafang G510, the motor Bafang also sells as the M620. Bafang's own M620 page rates it at 1000 W with a maximum torque of 170 N·m, so Eunorau's 160 is the more conservative of the two figures.

The torque sensor matters as much as the motor. Eunorau publishes a torque sensor rather than a cadence sensor. A cadence sensor answers one question — are the pedals turning — and delivers a fixed amount of assistance when the answer is yes. A torque sensor measures how hard you are pushing and scales the assistance to match, which is why a torque-sensed mid-drive feels like strong legs and not like a switch.

What you give up is weight and simplicity. 88 lb is heavy, the drivetrain wears faster than a hub motor's because the motor's torque runs through your chain, and a mid-drive costs more to build. On a bike bought for hills, those are reasonable trades. On a flat commute, a hub-drive bike does the job for less money.

The motor at the cranks, with the chain running back to the eleven-speed cassette it drives. That chain is the whole argument for a mid-drive on hills — and the part that wears for it.

How far the SPECTER-ST 2.0 goes: your range, gear by gear

On flat pavement a 180 lb rider gets about 48 miles from the 840 Wh main pack at 15 mph on the throttle, and about 90 with the free second pack mounted; at 20 mph the main pack gives 35. Hold 8 mph up an 8% grade in the 42T and one charge covers 13 miles on the throttle, against 7 in the 11T.

Your ride in three steps:

1. Find your speed and effort in the first two tables.
2. Add about 130 Wh for every 1,000 feet you climb, and climb in the big cogs (the gear tables).
3. Correct for your weight and the air temperature, then plan on 85% of what is left, the share Eunorau's charging advice leaves you to use.

Each figure is one steady ride priced from Bafang's published figures for the M620, the 40T chainring and 11–42T cassette Eunorau lists, coast-down measurements of everyday e-bike riders and a road-validated cycling-power model. The last subsection sets out the formula, the source of every input and one ride from wheel to pack.

Does riding faster cut range? Miles at each speed

Yes, and on the throttle speed matters more than anything else you choose. The main pack that lasts 48 miles at 15 mph lasts 35 at 20, about 27% less, and 21 at the 28 mph Eunorau's specification lists. The air is most of it: drag grows with the square of speed, and the power to push through it with the cube.

Throttle only, 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 turns most cheaply at that speed, with the chainring's rpm beside it. The second pack is the 48V 15Ah battery that ships free with the bike on September 26, 2026.

Pedal easily and the same main pack stretches from 48 miles to 76 at 15 mph. Seventy-five watts of your own, an easy effort, would carry this 88 lb bike about 9 mph on its own; 150 W carries it about 13.

Miles from the 840 Wh main pack, full charge, flat pavement, a 180 lb rider. "Legs alone" means your own watts already hold that speed, so the motor adds nothing. Past 100 miles the table stops counting, because a stop or a headwind decides the day. At 28 mph even the 11T asks for 92 rpm at the pedals, faster than the 90 rpm this model lets a pedaling rider turn.

The pedaling columns follow your legs, not an assist setting: an assist level is the controller's rule for how much to add, so find the row for the speed you hold and the effort you actually put in.

The White frame. Both colors ship with the same pair of packs: the 840 Wh main battery and the free 720 Wh second one, which carry the 15 mph throttle ride from about 48 miles to about 90.

What gear should you ride in to save battery?

On the flat, a middle-to-hard cog: at 15 mph the cheapest is the 13T, and every cog the motor can turn stays within 19% of it. On a climb, go the other way: in the big cogs an 8% grade costs 67 Wh a mile, and in the 11T it costs 115.

The M620 turns the chainring, so the cog you choose sets the motor's own speed. Bafang's figures put this motor's rated point at 180 rpm, well above a rider's cadence; on flat ground the load is light, and the motor loses least there at the lower chainring speeds a 13T or 15T gives. At 20 mph and up every usable cog lands within 6% of the best, so on fast flat roads the gear barely matters.

Flat pavement, a 180 lb rider, throttle only. Cogs are named by their teeth: the 42T is the biggest and easiest, the 11T the smallest and hardest. A cog the motor cannot drive at that speed is left out: its chainring would have to spin past the motor's no-load speed.

A hill turns the table around. Climbing 8% at 8 mph needs 115 Wh a mile in the 11T and 67 in the 42T, so the wrong gear costs 73% more for the same hill at the same speed. Pedal easily and the cheapest cog is the 36T; the 42T would need 100 rpm from your legs.

8 mph, a 180 lb rider; each cell is the battery cost per mile and the miles the main pack gives at that cost. "Past 90 rpm" marks a cog that asks the rider for more cadence than the model allows, following Hansen and colleagues, whose riders chose 72.4 rpm on their own and were held at 90 as the "relatively high" setting.

Does going uphill drain the battery faster?

Yes: each 1,000 feet of climbing costs about 130 Wh of the pack on top of the same miles on the flat, whether you pedal easily or not. Lifting 268 lb (a 180 lb rider on the 88 lb bike) through 1,000 feet takes 101 Wh at the wheel; the chain, the motor and the pack's own losses bring that to about 131 Wh drawn from the battery.

The 840 Wh main pack, spent on nothing but lifting, would climb about 6,400 feet, and both packs about 11,900.

A 180 lb rider. The first two columns are the fastest steady speed the M620 holds at its rated 1,000 W; on a 10% grade that is 14.9 mph on the throttle and 15.8 pedaling easily. The last column spends the whole main pack on that grade at 8 mph.

Price a hilly ride as flat miles plus climbing. Twenty miles at 15 mph on the throttle take about 347 Wh; add 2,000 feet at about 131 Wh per 1,000 and the ride uses roughly 609 Wh, which the main pack covers with Eunorau's 15% still in it. Every mile is priced as steady, so stops, starts and wind come on top.

Eunorau's FAQ names the MAX-CARGO and the JUMBO as the only models it builds that charge from pedaling, so on the SPECTER-ST descents return nothing to the pack.

Does rider weight affect range?

On the flat, a little; on a climb, a lot. From 130 lb to Eunorau's 300 lb limit, a 15 mph ride on the throttle falls from 52 miles to 41, and an 8% climb at 8 mph pedaling easily falls from 19 miles to 10.

You plus everything on the bike; the bike's own 88 lb is added to every row. Eunorau's payload guidance counts the rider and the load, and the 300 lb row is its limit.

Weight adds to what the tires and the hill cost and nothing to what the air costs, which is why the flat rows fall far less than the climbing column, which nearly halves.

Does cold weather drain the battery?

Yes: plan from the row nearest the day's temperature. At freezing, the 15 mph ride pedaling easily falls from 76 miles to 57, a quarter of the range. Eunorau's specification lists LG lithium-ion cells and its product record names both LG and Samsung, without a model number, so the central line uses McMaster University's measured LG HG2 cell and the brackets come from Samsung's data sheets and Casado and colleagues' cold test.

The pack's usable energy against 77 °F, and the miles a full main pack gives on flat pavement for a 180 lb rider: the central figure is the HG2 at a 0.5C discharge, the brackets the lowest capacity Samsung's data sheets print at that temperature and the highest energy measured at a gentler rate. The model assumes the cells sit at the air temperature.

Three things stack at 32 °F. The pack gives about 89% of its 77 °F energy, the air is 9% denser, and the tires roll 18% harder; together they cost the 15 mph ride a quarter of its miles. At 95 °F the range edges up, because thinner air and softer rubber outweigh the 1% the cells give up.

Do fat tires cut range? The Kenda Cursor and your riding position

The 3-inch Kenda Cursor is a street tread, and the model prices it from how everyday e-bikes actually roll. Kenda describes it as a tire whose "smooth center is quiet and fast", with "knurled side knobs" for corners. No lab or field measurement of the Cursor itself was found, so the central case is the rolling resistance measured on everyday e-bikes as ridden, bracketed below.

Miles from the main pack, flat pavement, a 180 lb rider. The low row is the field average for commuter tires; the high row the heaviest-rolling casings on Bicycle Rolling Resistance's drum.

Where your ride lands along these rows depends on your pressure and your roads as well as the tread. The model also takes the drag of a rider sitting up on flat bars; ride more upright, like the cruiser riders in the same survey, and the 20 mph throttle ride gives 33 miles instead of 35.

Is Eunorau's 80 miles real? The claim, matched to a ride

Eunorau's 80 miles is a two-pack figure, and the model shows a steady ride that earns it: 1,560 Wh over 80 miles is 19.5 Wh a mile, which is 16.9 mph on the throttle or 20.3 mph pedaling easily on flat pavement.

Eunorau ties its 80 miles to three different pairs. Its FAQ gives the figure "with the optional secondary battery installed", the 48V 15Ah pack that ships free; its specification row names a 17Ah main and a 17Ah second battery, and its product record a 17.5Ah main and a 17Ah second. All three readings are here.

The steady flat speed at which each pair's watt-hours, spread over 80 miles, match the model's cost per mile; a 180 lb rider at 77 °F with the whole of both packs used. The first row is the pair in the box.

Planned with 15% kept, the top of the 10 to 15% Eunorau's FAQ says to recharge at, the pair in the box gives 76 miles at 15 mph on the throttle and 120 pedaling easily. For a sense check from outside, Electrek estimated 60 miles on a dual-battery 2022 predecessor and states its pack two ways, 48V 14Ah in its spec box and "48v 15ah" in its text, so no consumption figure is derived from it.

How every figure here is worked out

A steady speed needs a steady flow of power at the rear wheel. Martin and colleagues' model, checked against riders on a real road in 1998, gives it without wind:

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

Here v is your speed, m the mass of you and the bike, g gravity, θ the slope, Crr the tires' rolling resistance (0.0103 means they drag with a force of 1.03% of the weight on them), ρ the density of the air and CdA your drag area, which is frontal size times shape. The first term is the tires and the hill, the second the air.

From the wheel back to the battery:

1. The chain passes 97.7% of the motor's work to the wheel, the drivetrain efficiency in Martin's model.
2. Your legs take their watts off the top; the motor supplies the rest, and a pedaling row keeps your cadence at 90 rpm or below.
3. The gear sets the motor's speed: the chainring turns at the wheel's rpm × the cog's teeth ÷ 40. Bafang's 2021 OEM workbook prints two no-load speeds for the M620, 150 and 190 rpm, beside two rated speeds, 140 and 180, two ratings, 750 and 1,000 W, and an efficiency of "≥ 80" percent, without pairing the columns. The model takes the 1,000 W pair for Eunorau's 1,000 W motor and turns those figures into a motor whose losses rise with current and with speed.
4. The pack loses a little more 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 = battery watts ÷ mph, and miles = 840 Wh × the share of the pack's energy the temperature leaves you ÷ watt-hours per mile.

One ride, worked through: 15 mph on flat pavement, throttle only, a 180 lb rider. Rolling resistance takes 82.3 W and the air 103.3 W, so the wheel needs 185.7 W and the chainring 190.1 W.

In the 13T the chainring turns 58 rpm, and the motor model (back-EMF 2.412 N·m per amp, 0.103 Ω winding resistance, 2.519 A no-load current) delivers 31.2 N·m at 75.5% efficiency, drawing 251.7 W. The pack's own losses bring that to 260.3 W: at 15 mph, 17.4 Wh a mile, and 840 ÷ 17.4 is 48 miles.

The model was checked before its numbers were used. It reproduces Martin's worked example to the tenth of a watt.

No measurement of the M620's efficiency was found, so the 85% at its rated point is the value, above Bafang's 80% floor, at which the model's efficiency surface lands closest to the mid-drive map Arango, Lopez and Ceren measured: within 5.2 points at its seven readings, where the floor misses by 14.2.

At the floor itself the 15 mph throttle ride gives 44 miles instead of 48, and Bafang's other printed pair, 150 and 140 rpm at 750 W, gives 48.

Will the SPECTER-ST 2.0 fit you?

Eunorau's photograph shows the saddle 37.8 inches off the ground, about where the fit formula puts the median 5'4" rider; at 5'5", 68 of 100 riders need it higher, and at 5'7", 96 of 100 do. The step-through's 19.3-inch standover leaves 95 of 100 riders at 5'3" at least 9.5 inches of room.

You lean 28 to 34 degrees from upright to reach the grips, and with your back fully relaxed your hands carry at most 19 to 24 percent of your weight.

Every figure is worked out for the 6,068 measured bodies in the US Army's anthropometric survey, with the saddle at 109% of inseam, on the frame as Eunorau photographed it.

Three steps to your fit on this bike:

1. Measure your inseam barefoot. Back against a wall, pull a hardcover book up firmly between your legs the way a saddle would sit, and measure from the floor to the book's top edge.
2. Find your height in the tables below and check that your inseam sits inside that row's range; a longer inseam reads like the next row up.
3. Set the saddle when the bike arrives with the knee and heel checks near the end of this section.

Eunorau prints two rider windows and a saddle range for the SPECTER-ST 2.0. The product page gives 5'3" to 6'4". Its frame-size guide puts a 19-inch frame, the size Eunorau's geometry table names, in its 5'6"–5'10" and 5'10"–6'1" rows.

The same specification lists the saddle at 32.3 to 34.3 inches from the ground, and Eunorau's own drive-side photograph shows it at 37.8 inches with post still showing above the clamp. The photograph's saddle sits above that range, so the tables below work from the photograph, and the post's full travel is the number to confirm with us.

Will the saddle go high enough for me?

Up to 5'4", the saddle in Eunorau's photograph already sits at or above the median rider's formula height; from 5'5" up, you raise it. The formula puts your saddle at 109% of your inseam from the pedal axle (Peveler et al., 2005), and published practice runs as low as 106% (Ferrer-Roca et al., 2012).

On this frame that distance becomes a height off the ground through a crank axle 12.2 inches up, the 170 mm cranks Eunorau lists and a seat post leaning at 73.7 degrees.

Ground-to-saddle height the formula gives the median rider at each height, where the saddle Eunorau photographed sits against it, and how many riders of 100 at that height need it set higher than the photograph shows. ANSUR II bodies, men and women together.

How far the post rises above the photographed setting is the one number to settle before you order if you are 5'5" or taller. A rider whose inseam sits at the long end of a row reads like the row above it.

Can I put a foot down at a stop?

Yes, with room to spare: this is where the step-through earns its price. Eunorau's geometry table gives the standover as 19.3 inches, the frame's low point behind the motor, and even at 5'3" 95 of 100 riders clear it by 9.5 inches or more.

Barefoot inseam minus Eunorau's published 19.3-inch standover: the clearance 95 of 100 riders at each height have or exceed.

That clearance is what lets a rider stand flat-footed over the frame at a stop, and it is why the SPECTER-ST reaches riders a high-step full-suspension frame does not. Eunorau publishes the full geometry as text beside a lettered diagram:

A 615 mm top tube on a frame with no top tube is not a misprint: in Eunorau's diagram the H line runs level from the seat post to the head tube, across the opening, so it is the cockpit length to set beside a conventional frame's chart.

Eunorau's lettered diagram; G is the 19.3-inch standover.

Will I feel cramped, or stretched?

The median rider leans 28 degrees from vertical at 5'3" and 34 at 6'4" to reach the grips as photographed, and the lean grows with height. The grips sit 21.6 to 22.9 inches ahead of the crank axle and 30.3 to 32.0 inches above it, and a taller rider's saddle rises with the formula while the bars stay put, so the trunk tips further.

The stem is adjustable, and Eunorau's geometry table gives a handlebar height of 42.5 inches where the photograph reads 44.4, so the lean below belongs to the photographed setting. If comfort on long, easy miles is the goal, tilt the stem up: in a 20-rider study, "Upright trunk was found to be the most comfortable position for recreational cyclists" (Priego Quesada et al., 2017).

Lean from vertical for the median rider on the frame as photographed: the least a straight arm needs to reach the grips from where the sit bones rest. The range spans the saddle's sit zone and the grip's extent in the photograph.

How much weight goes through my wrists?

At most 19 to 24 percent of your weight with your back fully relaxed, rising with height for the same reason the lean does. For scale, 10 road racers pedaling with their hands on the hoods put 15% of their weight on the stem (Carahalios, 2015); this cockpit's relaxed-back ceiling sits above that at every height.

The most the hands hold with the back relaxed, from each body's segment weights (Clauser et al., 1969); the range spans the saddle and grip positions. Weights are the survey's median at each height.

Your core carries part of that load on any real ride, which is why the table reads as a ceiling. Two things lower it: tilting the adjustable stem up, and, on a longer day, padded gloves, which cut the pressure over the ulnar nerve by 10 to 28% in a study of 36 experienced cyclists (Slane et al., 2011).

How do I set the saddle when it arrives?

Raise the saddle until your knee keeps a 25 to 35 degree bend with the pedal at its lowest point (Peveler et al., 2007). The quick way there is the heel method: heel on the low pedal, saddle up until that leg is just straight, which put 70% of 19 trained cyclists inside the range, more than either inseam formula did (Peveler et al., 2005).

Loosen the seat clamp, set the height with the bike upright and your heel on the pedal, and tighten the clamp again before the first ride.

How we computed fit

The saddle goes 1.09 times your inseam above the pedal axle; the lean is the smallest trunk angle at which a straight arm reaches the grip; the hand load is the upper body's weight carried through that lean, divided by the distance to the grip.

Take a 5'8" rider with the survey's median 32.6-inch inseam. The saddle belongs 35.6 inches from the pedal axle, which is 28.9 inches from the crank axle once the 170 mm crank is taken off (the LeMond route, 88.3% of inseam, gives 28.8). At this frame's 73.7-degree post that is 39.9 inches from the ground, 2.1 inches above the saddle as Eunorau photographed it.

Before anything was read off the photograph, its scale was checked against Eunorau's own table.

Scale from the published 51.3-inch wheelbase, axle center to axle center. Four figures land within 3.5% of Eunorau's; its stack figure measures something other than the vertical to the head tube's top, so it is shown and never used, and the model carries the bracket height at both values.

The formula checks out on the survey itself: across its bodies, the LeMond route plus a 170 mm crank lands at 109.0% of inseam from the pedal, against the 109.2 ± 0.9% measured in trained cyclists (Peveler et al., 2005). The hand figure is a ceiling: its only measured anchor is the road racers above, in a lower posture.

Full suspension: 140mm up front, a DNM shock behind

The fork is a EUNORAU unit with 140mm of travel, compression adjustment and a lockout. The rear is a DNM AO-38RC listed at 165mm. Eunorau's SPECTER-S 4.0 page describes its own AO-38RC as a "190mm eye-to-eye shock length with 50mm travel", length and travel as separate figures, so read the ST's 165mm as the shock's length.

140mm of front travel covers roots, rock and washed-out fire road. The lockout does more work than the number if you spend time on pavement: it stops the fork bobbing under a torque-sensed motor's power.

The fork, photographed on a trail by Eunorau. 140mm of travel with a lockout, per Eunorau's page.

The DNM AO-38RC in the frame.

The "Class 3" label and the statute

Before you order, tell us your state and how you intend to ride, and we will work through what its definition means for a 1000 W motor.

Eunorau's hero strip reads "CLASS: Class 3 Speed limited Unlockable." Eunorau's own FAQ says the throttle's permitted use "may vary by location, so riders should check applicable local e-bike regulations", and the statute is where that check starts.

California's definition is the one quoted here: its text is short, its three-class vocabulary is the one this label is written in, and no other state's statute is read on this page (Limitation 8). Cal. Veh. Code § 312.5, read in full from the Internet Archive's capture of August 24, 2026, reads, in relevant part:

(a) An "electric bicycle" is a bicycle equipped with fully operable pedals and an electric motor that does not exceed 750 watts of power.

The motor here is 1000 watts. That is 250 watts over the ceiling, and the ceiling sits on the definition of an electric bicycle itself; no class inside it is exempt. The federal definition draws its line at 750 watts as well — phrased "less than 750 watts" at 15 U.S.C. § 2085(b) — and so does the CPSC's bicycle regulation at 16 C.F.R. § 1512.2(a)(2).

The statute's class 3 definition adds a second test. Section 312.5(a)(3) defines that class as "a bicycle equipped with a motor that provides assistance only when the rider is pedaling, that is not capable of exclusively propelling the bicycle … and that ceases to provide assistance when the bicycle reaches the speed of 28 miles per hour, and equipped with a speedometer."

Eunorau's own FAQ says this bike has a throttle. Asked "Does it have both pedal assist and a throttle?", the page answers: "Yes. The bike offers five pedal-assist levels and a thumb throttle." The statutory test is capability: a machine a throttle can move on motor power alone is what the class 3 definition excludes — § 312.5(a)(4) permits motor-alone movement for start assistance or a walk mode, capped at 3.7 mph.

The speed figure, on its own, fits class 3. Eunorau's specification gives a 28 mph maximum, which is the class 3 ceiling to the mile; the wattage and the throttle are what the definition turns on.

Section 312.5(c) requires manufacturers and distributors to affix a permanent label to each electric bicycle carrying "the classification number, top assisted speed, and motor wattage." Section 312.5(c)'s duty attaches to electric bicycles as the code defines them, so the label question circles back to the wattage.

None of this makes the bike unlawful to own, and the pattern reaches well past this listing — our review of a 5,000 W machine met the same class question at five times the wattage.

What the wattage changes for you is where you may ride. States that adopted the three-class model wrote their own versions of the definition quoted above, and the wording varies.

Where a state routes bike-lane and trail access through a class definition, a machine outside the definition does not inherit the access. Our state-by-state guide carries each state's statute if you want to read yours.

Is the battery UL certified?

Eunorau's strip states "UL CERTIFIED: Yes." UL 2849 certifies the whole electrical system (motor, controller, charger and battery as one), while UL 2271 certifies the battery pack by itself, and an insurer or building manager may ask which one stands behind the two packs in the box. If yours does, we get the certificate from Eunorau before you pay for the bike.

The Mercer fit test

The Mercers are our editorial cast — a fixed group of American riders of different ages, heights and lives that every machine on this site is measured against. Every verdict reads a published number, confirmed at the manufacturer's page.

The numbers each verdict reads: the 19.3-inch standover, the saddle as Eunorau photographed it (37.8 in) beside the fit model's row at each height, the published 5'3"–6'4" rider range, the 300 lb payload, 88 lb, a torque-sensed 1000 W mid-drive, and the class question above.

The saddle Eunorau photographed sits 37.8 inches off the ground, above the 32.3 to 34.3 inches its specification lists, so ask us for the seat post's travel if you are 5'5" or taller.

Read Frank's row against Maya's. The frame works for both, with Frank's saddle raised further; what separates them is where they ride, because Maya's commute runs on bike infrastructure and the class question decides whether that is open to her.

Frank and Jack get a yes that turns on the seat post's travel, and Ruth one that turns on the bike's weight; Dana's is a yes on fit and a no on mission; Maya's turns on where she rides. On a full-suspension machine, the standover is what makes even that list possible.

Warranty

Both batteries ship in the box here, so the battery term matters; the Eunorau brand profile sets it beside the frame cover.

Eunorau's published cover runs 10 years on the frame and 24 months on the battery, the motor and the electrical components, against manufacturing defects, with wear items and labor excluded.

Four of the policy's six requirements are worth knowing before you buy. The policy runs to "the original purchaser" and states that the "Warranty does not transfer to another owner" — bought used, the cover is gone. Requirement 2 asks for "Product Registration right after the purchase", and Requirement 3 for an "E-bike check-up by a Eunorau specialist or dealer after the first year of use."

And Requirement 6 says products "sold at wholesale or purchased by a business for commercial use (e.g., rental fleets, delivery services, sharing programs) are subject to a 50% reduction of the standard Warranty period", a clause for buyers who are businesses rather than people.

Warranty claims on anything bought from us are handled by us. You send us the fault; we deal with Eunorau.

Ordering, shipping and support

The value case in numbers. $2,999 buys the bike and a second 48V 15Ah battery, a $499 value on Eunorau's page that Eunorau also includes free, so the box holds 1,560 Wh at the maker's own price. With Shop Pay, a $2,999 purchase could be split into 12 monthly payments of $270.68 at 15% APR, on the plans our listing offered on September 26, 2026.*

*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.

The honest ledger

Green flags

• A 19.3-inch standover on a full-suspension frame — the geometry that carries the whole review.
• A 1000 W Bafang G510/M620 mid-drive at 160 N·m, with the gearing to use it.
• A torque sensor in place of a cadence sensor.
• SRAM NX 1×11 with an 11–42T cassette, the eleven gears the mid-drive climbs through.
• 4-piston hydraulic brakes on 180mm rotors with motor cutoff.
• 140mm fork with lockout and a DNM AO-38RC rear shock.
• 1,560 Wh in the box — the 840 Wh main pack plus the 720 Wh second battery, included free ($499 value, verified Sep 26, 2026).
• A decade of frame cover — 10 years, with 24 months on the electrical system.
• A published 12-row geometry table, standover included, with a 5'3"–6'4" rider range and a 300 lb payload rating beside it.

Red flags

• A 1000 W motor is over § 312.5's 750 W line, and the thumb throttle is outside its pedal-assist class 3; read the class section before you count on bike-lane access.
• Riding past about 48 miles at 15 mph on the throttle: mount the second pack, which comes in the box; the range tables price both packs.
• A 300 lb payload for rider and cargo combined; loads over that belong on a higher-rated machine such as the FAT-HD 2.0, rated for 375 lb.
• 88 lb. Fine to ride, hard to lift, and a two-person job onto a car rack; plan storage and transport first.

Who should buy it

Buy the SPECTER-ST 2.0 if you want to climb real hills, you want suspension at both ends, and you want to step through the frame rather than over it. Of the 211 active listings tagged e-bike in our catalog on September 25, 2026, it was one of two that attempt that combination, and the only one of the pair built as an eMTB.

Buy something else if you do not need the step-through. The SPECTER-S 3.0 is the alternative, with the same money and the same motor on a full-frame chassis, orderable in Army Green on September 26, 2026; our full SPECTER-S 3.0 review covers it.

The third route is the hardtail FAT-HD 2.0 / Hunter X7 from $2,399: a 1000 W, 160 N·m Bafang mid-drive, cadence-sensed rather than torque-sensed, with a 375 lb payload rating.

Do not buy it if you need to lift it, or if your riding is flat commuting where a hub-drive bike does the job for less.

Before you buy: the checklist

Nine things to settle before the SPECTER-ST ships. The first three decide whether it fits your loads, your routes and your height; the rest take a few minutes each and protect your return window.

• ☐ Count the 300 lb as rider and cargo combined; the bike's own 88 lb is separate.
• ☐ Price a hilly route with the range tables: about 130 Wh for every 1,000 feet of climbing on top of the flat miles, and mount the free second pack for the long days.
• ☐ Check your height and inseam against the fit tables; from 5'5" up, settle the seat post's travel before you order.
• ☐ Settle the class question for your state if bike-lane access is the point.
• ☐ Confirm ground-floor storage — 88 lb does not go up stairs.
• ☐ Work out how it gets transported before it arrives.
• ☐ Get the UL standard number from us if your insurer or building asks for one on the batteries.
• ☐ Photograph the crate before you open it — transit damage has to reach us inside 48 hours.
• ☐ Decide before you build it: once this bike is assembled, the return window is closed.

Limitations of this review

Twenty-two limits on what this review can tell you, numbered so you can check each one against the section it qualifies before you lean on the verdict.

1. Every bike specification on this page is Eunorau's own, verified at its page and recomputed. The range and fit models, Electrek's estimate, the catalog screen and our own price and payment terms are the exceptions, each named below.
2. Every range figure is a steady ride: a held speed on a constant grade, no wind, no stops. Starting, stopping and headwinds cost more; a tailwind costs less.
3. Electrek's 60-mile figure is that reviewer's estimate on the 2022 predecessor, on a dual-battery setup whose pack sizes the review states inconsistently — 48V 14Ah in its spec box, "48v 15ah" in its text. It is used as a sense check and no consumption figure is computed from it.
4. Payload, rider height and maximum speed are read from Eunorau's specification block on September 24, 2026, and re-read September 26: 300 lb, 5'3"–6'4" and 28 mph. The August 29, 2026 copy of the page carried none of the three; the expiry condition below covers all of them.
5. Eunorau prints a 28 mph "Maximum Speed" and the words "Speed limited Unlockable" without saying which setting the 28 mph describes, and it publishes no figure for an unlocked setting.
6. The UL standard is not named on Eunorau's page; we report the claim as printed.
7. Eunorau's 80 miles is mapped for three battery pairs, the FAQ's 17.5Ah main with the free 15Ah pack, the specification's 17Ah pair and the product record's 17.5Ah and 17Ah, because Eunorau ties the figure to all three.
8. The class analysis is California's statute. States that adopted the three-class model wrote their own versions, the wording varies, and no other state's rule is asserted here.
9. Recalls were screened on September 24, 2026 in the CPSC's recall database, on three query fields that each returned recalls for a control term in the same run; none names Eunorau or the SPECTER. The CPSC's complete product safety warning listing, read September 25, 2026, names neither; of its 372 warnings, the same check found both of the two it already knew of for another brand.
10. No search-volume figures appear here. We do not publish numbers we cannot source.
11. The two-of-211 catalog figure is our own screen of our own store, run September 25, 2026 with a narrow and a wide pattern pass, every candidate either pass returned hand-checked against its listing; the screen and its verdicts are saved with this page's dataset. It counts our shelf, not the market.
12. Our price, the free second battery and the Shop Pay terms are read from our own listing on September 26, 2026; the 12-month payment is computed from the listing's plan table at 15% APR.
13. The motor's efficiency is fitted, not measured. Bafang prints the M620's efficiency as a floor, "≥ 80" percent, and no measurement of this motor was found, so the model takes 85% at the rated point, where its efficiency surface lands closest to the measured map of another 48 V mid-drive (within 5.2 points); at Bafang's floor the 15 mph throttle ride gives 44 miles instead of 48.
14. Bafang prints two sets of M620 speeds without pairing them. The model uses the 190 and 180 rpm pair for Eunorau's 1,000 W rating; the 150 and 140 rpm pair at 750 W gives the same 48 miles at 15 mph on the throttle.
15. No measurement of the Kenda Cursor tire was found. The tables price it at the rolling resistance measured on everyday e-bikes as ridden (0.0103) and show the commuter-tire and heaviest-casing figures beside it.
16. Eunorau names LG cells in its specification and both LG and Samsung in its product record, without a model number, so the cold rows use McMaster University's measured LG HG2 and bracket it with Samsung's data sheets; the second pack's weight is not published and is not in the model.
17. The fit figures describe Army bodies, not the public. The 6,068 people in the ANSUR II survey are US Army personnel aged 17 to 58, measured in 2010 to 2012; how inseam, torso and arm length vary at a given height carries over to civilians, the exact spread may not.
18. The cockpit is the one Eunorau photographed. The grips, the seat post and the saddle were measured on one studio photograph; the stem is adjustable, Eunorau's table gives a lower handlebar than the photograph shows, and where the sit bones rest on this saddle is not published, so the tables span its rear-middle quarter.
19. The saddle's travel is not settled. Eunorau's specification lists the saddle at 32.3 to 34.3 inches from the ground and its photograph shows it at 37.8, so the saddle table compares each height with the photograph and the post's full travel is the number we request from Eunorau for you.
20. The hand figure is a ceiling. It assumes the back is fully relaxed, so the hands hold everything the trunk does not; any core effort lowers it, and its only measured anchor is road racers on the hoods, a lower position than this.
21. The formula is a starting point. In 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), so set the final height on the bike.
22. Expiry: re-verify if Eunorau changes the specification's payload, rider-height, speed or range figures, publishes the seat post's travel or a UL certificate, ends the free second-battery offer at either store, or if the price moves.

The source register

Every source this review cites, graded by tier: Eunorau's own pages and records, the state and federal statutes, the federal recall and warning lists, and our own first-party datasets, each beside what it was used for.

Frequently asked questions

Is the Eunorau SPECTER-ST 2.0 really a Class 3 e-bike?

Eunorau labels it Class 3; check that against your state's definition before you rely on it. Cal. Veh. Code § 312.5(a) defines an electric bicycle as having "an electric motor that does not exceed 750 watts of power", and this motor is 1000 W.

Section 312.5(a)(3) adds that a class 3 machine is "not capable of exclusively propelling the bicycle", and Eunorau's own FAQ says this one has a thumb throttle.

Do mid-drive e-bikes have a throttle?

Many do, and this one does — Eunorau's FAQ says "five pedal-assist levels and a thumb throttle". It is worth knowing because a throttle is what separates the class definitions: a class 3 machine under California's statute may not be capable of propelling itself except for start assistance or a walk mode up to 3.7 mph.

What is the real range of the Eunorau SPECTER-ST 2.0?

On flat pavement a 180 lb rider gets about 48 miles at 15 mph on the throttle from the 840 Wh main pack, about 90 with both packs, which ship together as of September 26, 2026, and 35 from the main pack at 20 mph. Pedaling easily at 15 mph stretches the main pack to 76 miles.

Eunorau's "up to 80 miles" is a two-pack figure: spread over the pair in the box, it is a steady 16.9 mph on the throttle. The range tables price your own speed, hills, weight and temperature.

How low is the standover on the Eunorau SPECTER-ST 2.0?

490mm, or 19.3 inches, from Eunorau's published geometry table. That is the figure that lets a rider step through the frame rather than swing a leg over it; on our 211-listing shelf on September 25, 2026, it was one of two step-through, full-suspension, mid-drive machines.

What size rider does the Eunorau SPECTER-ST 2.0 fit?

Eunorau's window is 5'3" to 6'4". A 5'4" rider with the survey's median 30.5-inch inseam needs the saddle 37.7 inches off the ground, where Eunorau photographed it; a 5'8" rider with a 32.6-inch inseam needs 39.9 inches, 2.1 above that, so from 5'5" up ask us for the seat post's travel.

The 19.3-inch standover leaves 95 of 100 riders at 5'3" at least 9.5 inches of room (the fit tables).

How much does the Eunorau SPECTER-ST 2.0 weigh?

40 kg, or 88 lb, from row L of Eunorau's published geometry table. On the road that weight mostly disappears under a 160 N·m motor; at the garage door it means ground-floor storage and a two-person lift onto a car rack.

What motor does the Eunorau SPECTER-ST 2.0 use?

A Bafang G510, also sold as the M620 — a 1000 W mid-drive that Eunorau rates at 160 N·m, driven through a torque sensor in place of a cadence sensor. Bafang's own page rates the motor at 1000 W with a 170 N·m maximum.

Is a mid-drive better than a hub motor for hills?

On a bike like this one, yes. A mid-drive drives the chain, so it uses your gears; drop into the 42-tooth sprocket and the motor's torque is multiplied by the same ratio your legs get. A hub motor is stuck in one effective gear. The trade is weight, drivetrain wear and cost.

Does the Eunorau SPECTER-ST 2.0 have a UL certificate?

Eunorau lists it as "UL CERTIFIED: Yes". UL 2849 covers the whole electrical system and UL 2271 the battery pack alone; if you need to know which stands behind these batteries, we get the certificate from Eunorau on your behalf.

What is the payload capacity of the Eunorau SPECTER-ST 2.0?

300 lb, per Eunorau's specification block, of rider and cargo combined; Eunorau defines payload as "the rider and anything carried on the bike itself", so the bike's own 88 lb sits outside it. The same specification gives a 5'3"–6'4" rider range. For heavier loads, the FAT-HD 2.0 is rated for 375 lb.

Has the Eunorau SPECTER-ST 2.0 been recalled?

The CPSC's recall database lists no recall naming Eunorau or the SPECTER, checked September 24, 2026 on three query fields that each returned recalls for a control term in the same run, and the CPSC's product safety warning listing, read September 25, 2026, names neither.

What is the warranty on the Eunorau SPECTER-ST 2.0?

Eunorau covers the frame for ten years and the battery, motor and electrical components for 24 months, against manufacturing defects.

Four of the policy's six requirements matter before you buy: the cover stays with the original purchaser only, the bike must be registered right after purchase, a check-up by a Eunorau specialist or dealer is due after the first year, and a commercial or wholesale purchase halves the standard warranty period. Buy it here and we run the claim for you.

What is the difference between the SPECTER-ST 2.0 and the SPECTER-S 3.0?

The ST is the step-through; the S is the full-frame version. The ST is $2,999 on our shelf and the S is $2,999, orderable in Army Green on September 26, 2026; both run the 1000 W Bafang mid-drive. Choose the ST if getting on and off matters, the S if it does not.

The bottom line

The SPECTER-ST 2.0 pairs a serious climbing motor and suspension at both ends with a 19.3-inch standover — in our 211-listing catalog on September 25, 2026, only one other machine attempted the combination.

If you have been choosing between a bike you can get onto and a bike that can climb, this is the machine that stops making you choose. Our reviews index lists it among the fits for riders under 5'4".

One thing to check before you pay: at 1000 watts the motor is over § 312.5's 750-watt line, so confirm what your state allows before you count on class 3 access.

That does not change what the bike does. It changes where you can ride it.

Both batteries are in the box. A 180 lb rider gets about 48 miles at 15 mph on the throttle from the main pack and about 90 from both on flat pavement, and the range tables price your hills, weight and temperature.

Buy it if the hill is the problem and the top tube is the other problem.

References

1. Eunorau. SPECTER-ST 2.0 — product page and product record: stat strip, specification block, Components list, geometry table, accessories and FAQ. eunorau-ebike.com/products/specter-st-1. Retrieved August 29, September 24, September 25 and September 26, 2026; deposit copies and all eleven linked images archived, plus an August 13, 2026 spec-row extraction.
2. Eunorau. Hunting Ebike Trailer Guide: How Much Gear Can You Tow. eunorau-ebike.com. May 31, 2026; retrieved September 24, 2026. Eunorau's own definition of payload.
3. California. Vehicle Code § 312.5 — Electric bicycle. Pinpoints § 312.5(a), (a)(3), (a)(4) and (c). Internet Archive capture of August 24, 2026, web.archive.org.
4. United States. 15 U.S.C. § 2085 — Low-speed electric bicycles. Pinpoint § 2085(b). U.S. Government Publishing Office, govinfo.gov. Retrieved August 29, 2026; snapshot of August 24, 2026.
5. United States. 16 C.F.R. § 1512.2 — Definitions. Pinpoint § 1512.2(a)(2). eCFR, current as of August 29, 2026, deposit copy archived; snapshot of August 25, 2026.
6. Electrek (news organization; sense check only, never load-bearing). EUNORAU Spectre-ST review: Comfort and excess on two wheels. electrek.co, September 9, 2022. A review of the previous generation; its battery figures are internally inconsistent (14Ah spec box, 15Ah text), so only its labeled 60-mile estimate is reported.
7. UL Standards & Engagement (standards body; context only). UL 2849 and UL 2271. Retrieved August 29, 2026.
8. Bafang. BAFANG Motors M-Series — M620. bafang-e.com. Undated; retrieved August 29, 2026, deposit copy archived.
9. Eunorau. 24-Month+ Limited Warranty. eunorau-ebike.com/pages/warranty. Deposit copy August 28, 2026.
10. U.S. Consumer Product Safety Commission. SaferProducts recall database. saferproducts.gov/RestWebServices/Recall. Screened September 24, 2026 on the RecallTitle, RecallDescription and ProductName fields, each passing a positive and a negative control; no recall names Eunorau or the SPECTER.
11. Redtail eBikes. SPECTER-ST 2.0 store record (redtailebikes.com/products/eunorau-specter-st) and refund policy. Retrieved August 29, September 24, September 25 and September 26, 2026. First party.
12. Redtail eBikes editorial desk. SPECTER-ST battery and range computation. Pack energy as volts × amp-hours from Eunorau's battery ratings, and the 12-month payment from our listing's Shop Pay plan table at 15% APR. Computed September 25, 2026. First-party dataset.
13. Redtail eBikes editorial desk. Catalog screen: step-through + full suspension + mid-drive across 211 active listings. Every active listing tagged e-bike on our store, read with a narrow and a wide pattern pass on September 25, 2026, each candidate either pass returned hand-checked against its listing. First-party dataset; it counts our shelf alone.
14. Eunorau. SPECTER S 4.0/Hunter X9 — product page. eunorau-ebike.com/products/specter-s-hunter. Retrieved September 24, 2026; deposit copy archived. Cited only for how Eunorau writes the AO-38RC's length and travel.
15. Affirm. Lending partners. affirm.com/lenders. The lenders behind Shop Pay's installment plans, named in Shopify's installment terms.
16. U.S. Consumer Product Safety Commission. Product safety warning listing (complete CSV). cpsc.gov. Read September 25, 2026: 372 warnings, 2 naming the control brand, none naming Eunorau or the SPECTER; deposit copy and screen archived.
17. Bafang. Workbook OEM 2021, MOTORS table, M620 (MM G510.750.C / MM G510.1000.C) column: rated voltage, n0, rated power, nT, maximum torque and efficiency. bafang-e.com. Retrieved September 23, 2026; deposit copy archived.
18. 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.
19. 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; doi 10.1080/02640414.2018.1458587. civil-reactlab.sites.olt.ubc.ca. Retrieved September 23, 2026.
20. 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), Eq. (40) and Fig. 5; doi 10.3390/wevj12020059. mdpi-res.com. Retrieved September 23, 2026.
21. 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.
22. 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.
23. 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.
24. 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.
25. 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.
26. 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.
27. 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.
28. Kenda. Cursor (product page: tread description, sizes and casing). shop.kendatire.com. Retrieved September 26, 2026; deposit copy archived.
29. Bicycle Rolling Resistance. Kenda Juggernaut Pro (fat-bike drum test, 12 psi). bicyclerollingresistance.com. Retrieved September 25, 2026.
30. SRAM. PG-1130 Cassette, CS-PG-1130-A1 — Specifications, cog sizes for the 11–42T. sram.com. Retrieved September 23, 2026.
31. Eunorau. EUNORAU EBIKES FAQ: "How long does the battery last?" and "Does the battery charge when pedaling and/or braking?". eunorau-ebike.com/pages/faqs. Retrieved September 26, 2026.
32. Eunorau. Frame Size Suggestion (rider height against frame size). eunorau-ebike.com/pages/frame-size-suggestion. Retrieved September 26, 2026.
33. 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.
34. 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.
35. 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.
36. 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.
37. Priego Quesada, J. I. et al. Effect of bike-fit in the perception of comfort, fatigue and pain. Journal of Sports Sciences 35(14):1459–1465 (2017). pubmed.ncbi.nlm.nih.gov. Retrieved September 25, 2026.
38. 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.
39. 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.
40. 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.
41. Redtail eBikes editorial desk. SPECTER-ST 2.0 range model. The computation set out in the range section of this review, Martin et al.'s power model with Bafang's M620 figures; run September 26, 2026. First-party computation; every input and its source in its inputs table.
42. Redtail eBikes editorial desk. SPECTER-ST 2.0 fit model. The computation set out in the fit section of this review, for the ANSUR II bodies on the frame as Eunorau photographed it, the photograph's scale checked against Eunorau's table; run September 26, 2026. First-party computation; every input and its source in its inputs table.

Image credit: every photograph on this page is Eunorau's own. The cover at the top of this page and the card inside it are Eunorau's photograph of the SPECTER-ST 2.0 in Black, softened toward its edges to fit the cover and set with type in real fonts; the side views, component close-ups and geometry diagram are Eunorau's product images.