Freesky Alaska Pro M-520 Review 2026: $1,899, 2,160 Wh

Full-suspension fat tire · one 4,500 W peak rear hub motor · 170 N·m · 48 V 45 Ah in two packs, 2,160 Wh · 98–175 miles on pedal assist · 20 mph by default · 90 lb · 400 lb capacity · Freesky's rider range 5'6" to 6'8" · $1,899 · verified September 25, 2026

Quick Answer — The Freesky Alaska Pro M-520 is a $1,899 full-suspension fat-tire e-bike with one 4,500 W peak rear hub motor, 170 N·m, and two removable packs, 18 Ah and 27 Ah, 2,160 Wh together. On flat pavement a 180 lb rider gets a computed 123 miles at 15 mph on the throttle.

At 20 mph the same full charge runs about 87 miles, and Freesky's own figure is 98 to 175 miles on pedal assist. The range section turns that into your ride: speed, hills, load, weather, tires, and one pack or both.

The speed rule comes first. Freesky publishes 40 mph, and its FAQ says its bikes are limited to 20 mph by default and that going faster needs "a license, license plates, and insurance"; the class section sets that beside the statutes.

What this review covers

What $1,899 buys · What it is · Will it fit you · The motor · The two packs · How far it goes · Brakes and lights · Suspension and tires · Weight and load · The Mercer fit test · UL · Recalls · The class question · Where to ride it · Green and red flags · The verdict · Checklist · Buying it from us · FAQ · Limitations · The bottom line · References

How we verified this Freesky Alaska Pro M-520 review

Each figure here was read on September 25, 2026 from Freesky's Alaska Pro M-520 product page, its product record, the Alaska Pro's own manual, Freesky's dual-battery FAQ, the two UL certificates Freesky links, our listing or the statutes quoted in the class section. The range figures are computed, and the formula names every input and its source.

This review is specification-verified: every number is Freesky's, a statute's, or arithmetic laid out on this page, and the model behind the range tables reproduces the published benchmarks it rests on and is set beside one filmed ride of this bike. We sell the Alaska Pro, so weigh the red flags as carefully as the green ones.

Written by Milad Ghobadibeygvand, BScN (Western University, 2014). Corrections: support@redtailebikes.com.

What $1,899 buys

Sources: Freesky's product page and product record, both read September 25, 2026. The headlight's rating is in the record's feature list; the chargers and keys are in the manual's box list; the 20 mph default is in the FAQ on the product page.

A 2,160 Wh fat-tire bike built around two packs

Freesky describes the Alaska Pro as "a dual-battery fat tire eBike built for exceptional range, powerful performance, and all-terrain capability". It is a full-suspension mountain-bike frame on 26 × 4-inch tires, with one hub motor in the rear wheel and two removable packs, "18Ah up top and 27Ah below" in Freesky's words.

From the front: the headlight, the 120 mm fork and the 26 × 4 tire.

The two packs are the reason to buy it. They add up to 2,160 Wh, either one can power the bike by itself, and the pack in the down tube holds half as much again as the one on the top tube.

Freesky's product record for the Alaska Pro dates from December 8, 2024, and the bike has changed since. Its dual-battery FAQ of June 10, 2026 says that "Depending on production batch and configuration" an Alaska carries 18 + 23 Ah (41 Ah) or 18 + 27 Ah (45 Ah); the product page lists the 45 Ah pair, and every figure here uses it.

From behind: the rear hub motor inside the wheel, the derailleur beside it, the rack and the tail light.

Will the Alaska Pro fit you?

The saddle reaches the height the fit formula asks for on 98 of every 100 riders at 5'4" and 80 of 100 at 5'6", then on 44 of 100 at 5'8" and 10 of 100 at 5'10"; Freesky's published window runs from 5'6" to 6'8". You sit 5 to 10 degrees from upright, and with your back fully relaxed your hands carry 9 to 12 percent of your weight.

Every figure is computed for the 6,068 measured bodies in the US Army's 2012 body survey, at 109% of inseam, on the cockpit in Freesky's drawing.

Three steps find your fit on this frame:

1. Measure your inseam. Stand in socks against a wall, pull a hardcover book up firmly where a saddle would sit, and measure from the floor to its top edge.
2. Find your height in the tables below. Check that your inseam falls inside the row's range; past an inseam of 32.5 inches, you ride the saddle at the top of its post.
3. Set the saddle when the bike arrives with the knee and heel checks at the end of this section.

Freesky publishes one frame, one rider window and one inseam range; its table and its drawing give different figures for the two measurements a short rider reads first.

Freesky's drawing, scaled by its published 47.4-inch wheelbase. The highest seat line agrees with the table; the lowest-seat and standover lines measure 35.9 and 31.5 inches.

Will the saddle go high enough for me?

For most riders up to 5'6"; from 5'8" up, most run out of seatpost before the formula's height. The fit formula puts your saddle 109% of your inseam from the pedal axle (Peveler et al., 2005), and the published range reaches down to 106% (Ferrer-Roca et al., 2012). On the Alaska Pro that becomes a ground height through its 12.9-inch crank axle, the 170 mm cranks Freesky fits to the Alaska and its 73° seat tube.

Ground-to-saddle height for the median rider at each height, and how many riders of 100 at that height have a 109% and a 106% saddle height inside Freesky's 30.7-to-40.7-inch seat range. ANSUR II bodies, men and women together.

Freesky's inseam range runs to 35 inches; the top of the post meets 109% of inseam at 32.5 inches, and 106% at 33.4. Above that, you ride with the saddle at its highest and your knee bent more than the formula asks at the bottom of the stroke.

Tall owners do ride it: an owner wrote on Freesky's page on January 15, 2025, "I am 6'2" and it fits me perfect", after more than 300 miles on the bike.

At the short end the two lowest-seat figures matter. At the 35.9 inches Freesky's drawing marks, the lowest saddle meets 109% of an inseam of 27.9 inches, beside the 27-inch minimum Freesky prints; at the listed 30.7 inches it would be 22.9. If your inseam is close to that, measure against both figures.

Can I put a foot down at a stop?

At Freesky's listed 28.7-inch standover, yes: 95 of 100 riders clear it by at least 1.5 inches at 5'6" and 2.4 inches at 5'8". The frame has no step-through, so you swing a leg over it to mount. On Freesky's drawing, scaled by the wheelbase, the top tube sits 31.5 inches up where the standover line is drawn, and at that height the same riders clear it from 5'10" up. Below 5'10", measure your inseam against both figures.

Barefoot inseam minus each standover figure: the clearance that 95 of 100 riders at each height have or exceed, with a minus sign where the frame sits above that inseam.

Will I feel cramped, or stretched?

Neither: the median rider sits 5 to 10 degrees from upright, because the grips ride 32.6 to 35.1 inches above the crank axle, higher than the saddle. In a 20-rider study, the most upright of the three trunk positions compared was the one recreational cyclists found most comfortable (Priego Quesada et al., 2017).

The angle is the least a straight arm needs to reach the grips from where your sit bones rest, worked out from each body's own torso and arm lengths.

Lean from vertical for the median rider; the range spans where the sit bones rest on the saddle and the grip's extent in Freesky's drawing.

How much weight goes through my wrists?

At most 9 to 12 percent of your weight, and only with your back fully relaxed. For scale, 10 road racers pedaling with their hands on the hoods put 15% of their weight on the bars (Carahalios, 2015); on the Alaska Pro's high grips the median rider's relaxed-back ceiling stays below that at every height in the table.

Leaning further forward loads the heel of the hand over the ulnar nerve, and in 36 riders that pressure peaked in the most leaned-over hand position (Slane et al., 2011).

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.

On a long day, padded gloves help: they cut that palm pressure by 10 to 28% in the same study.

How do I set the saddle when it arrives?

Set the saddle so your knee still bends 25 to 35 degrees at the bottom of the stroke (Peveler et al., 2007). Freesky's manual puts the same check in plain words: with a pedal at its lowest point and the ball of your foot on it, your leg "should be almost fully extended(not locked out) with a slight bend at the knee."

The heel method, heel on the low pedal and the saddle raised until that leg is just straight, put 70% of 19 cyclists in range, more than either inseam formula (Peveler et al., 2005). The same manual says: "DO NOT raise the seatpost beyond the minimum insertion marking etched into the seatpost tube."

How we computed fit

Saddle height is 1.09 × inseam from the pedal axle; lean is the smallest trunk angle at which a straight arm reaches the grip; hand load is the upper body's weight times its lean, divided by the reach to the grip.

A 5'8" rider with the median 32.6-inch inseam needs 35.6 inches from the pedal, which is 28.9 inches from the crank axle (88.3% of inseam gives 28.8), a ground-to-saddle height of 40.8 inches, just past the 40.7-inch top of the post.

The drawing was checked against Freesky's own figures before anything was read off it.

Scale from the published 47.4-inch wheelbase, measured axle center to axle center. Five labels differ from the lines they sit on, so the model reads the crank axle, seatpost and grips off the drawing, keeps Freesky's listed seat range and standover, and prints both.

One 4,500 W peak rear hub motor and 170 N·m

Freesky's page says: "The 4500W peak rear hub motor delivers an impressive 170 N·m of torque, reaching speeds of up to 40 MPH in both throttle and pedal-assist modes." Peak output is the short burst a motor can give; what it can sustain is its continuous rating, which the class section comes back to.

Freesky's hunting-bike guide of September 8, 2026 files the Alaska Pro under "Best for High Torque and Challenging Terrain".

The rear hub motor, with the seven-cog freewheel threaded on and the rotor on the far side; Freesky shows it on a Blue-gray frame.

A hub motor turns with its wheel, so the gears change your cadence and nothing about the motor. What moves the battery at a given speed is how hard you pedal, and the effort table prices it.

Assistance comes from a cadence sensor: once the cranks turn, the motor adds help at the level you pick from 0 to 5, and the thumb throttle moves the bike with no pedaling at all. The manual's first ride is gentle: "On a flat surface, in a low gear (1 or 2), most riders should be able to begin pedaling the bike with pedal assist level 0 or 1."

Two packs: 18 Ah up top, 27 Ah below, 2,160 Wh

48 V × 45 Ah is 2,160 watt-hours, and Freesky's page prints the figure itself: "2160Wh Dual Battery". The packs split it 864 Wh (18 Ah) and 1,296 Wh (27 Ah).

One pack on the top tube and one in the down tube, "18Ah up top and 27Ah below" in Freesky's words.

Two packs, and either one can run it. Freesky's dual-battery FAQ says: "The bike can operate with only one working battery." It adds that "No manual switching is required" and that "Each battery in the Alaska system is independent", so a failed pack can be replaced by itself.

The same FAQ answers whether one pack changes the speed: "Top speed and motor output are controlled by the motor and controller system." What one pack changes is how far you go:

Miles at 77 °F, flat pavement, a 180 lb rider, with both packs on the bike and one of them drained, so the weight is the same in every column: 864, 1,296 and 2,160 Wh.

Freesky's FAQ gives 45 to 80-plus miles for the 18 Ah pack alone, 70 to 120-plus for the 27 Ah and 120 to 200-plus for both. The model's 15 mph rides, from the throttle to easy pedaling, land at 49 to 80, 74 to 120 and 123 to 200.

Plan on about nine hours to charge both packs from empty. Freesky ships two chargers, a "US Standard 3A Smart Charger + 2A Smart Charger", and its chart gives 8–10 hours; by plain division, 27 Ah at 3 A and 18 Ah at 2 A each take 9 hours, so charge both overnight.

The FAQ allows both packs at once, one at a time, or just one, and recommends "keeping both batteries at similar charge levels" for "long-term balance".

Keep them dry, and charge and store them at 50 to 77 °F. The manual says the bike "is not intended to be used and stored" below 32 °F or above 104 °F, allows charging only in that same span, and asks you to "Charge and store bike and battery in a dry location, between 50 °F – 77 °F".

If a ride will not need the whole 2,160 Wh, Freesky's summer charging guide notes that "charging to 80–90% can reduce thermal and chemical stress."

Check which pair your bike carries. On the earlier 18 + 23 Ah pair, 1,968 Wh, each full-charge figure here is about 91% as long: 112 miles at 15 mph on the throttle instead of 123. Email us before you order and we will confirm in writing which pair the unit you receive carries.

How far the Alaska Pro goes: your range, one pack or both

On flat pavement, a 180 lb rider covers about 123 miles on a full charge at 15 mph on the throttle, 87 at 20 mph, and 200 at 15 mph with easy pedaling. Up an 8% grade at 10 mph on the throttle, the same charge lasts 18 miles.

To find your own figure:

1. Pick the speed you hold and the effort you give from the first two tables.
2. Set aside 200 to 278 Wh of the 2,160 for each 1,000 feet you climb (10 mph on the throttle, 4 to 10% grades), or 166 to 242 if you pedal easily (the hills table).
3. Correct for your load and the temperature, then plan on 80% of the answer.

Every table works out one steady ride at a time, from Freesky's specifications, Bafang's published figures for a comparable 48 V geared hub motor, drum measurements of ten 26 × 4.00 fat tires, the Alaska Pro's own tire size, and a road-cycling power model validated on a real road. The last subsection sets out the formula and works one ride through it.

Does riding faster cut range? Miles at each speed

On level ground, how fast you ride decides the range more than anything else in these tables. A full charge that lasts 123 miles at 15 mph lasts 87 at 20: the air's share of the load grows with the cube of the speed, so 20 mph asks about 2.4 times the air power of 15, the ratio (20 ÷ 15)³.

Throttle only, flat pavement, a 180 lb rider, 77 °F. The last column assumes an 80% charge, which Freesky's summer charging guide suggests when a ride will not use the whole pack. Rows above 20 mph price speeds beyond the default limit; the class section deals with them.

Pedaling lightly is the cheapest range you can add on the flat: at 15 mph, 75 W from your legs takes a full charge from 123 miles to 200. In these tables easy pedaling is 75 W from the rider and steady pedaling is 150 W.

Without the motor, 75 W would move this bike at about 8.9 mph on level pavement and 150 W at about 13.1, so pick the column that matches what you could hold on your own.

Miles from a full charge, flat pavement, a 180 lb rider; at 15 mph easy pedaling draws 10.8 Wh a mile against 17.5 on the throttle. In the 351-, 452- and 206-mile cells your legs out-push the motor, so those figures lean hardest on the model's least certain part, its motor losses at light load (Limitations item 5). "Legs alone" means 150 W holds 12 mph with the motor idle.

The assist level you pick sets how much the controller adds while you pedal, and nothing more. Whichever level you ride, read the row for the speed you hold and the effort you give; the manual says as much for hills, "Use lower PAS levels and pedal when climbing hills", and Freesky's FAQ lists "Throttle Only" as the "Shortest range".

Which gear saves battery? On a hub motor, your effort does

Shift for your legs; pedal for the battery. The hub motor turns with the rear wheel whatever gear you are in, so a shift changes your cadence and nothing about the motor. What changes the draw at a given speed and grade is how hard you push:

Watt-hours from the battery per mile, a 180 lb rider, 77 °F. Easy pedaling is 75 W from you, steady pedaling 150 W.

Up an 8% grade at 10 mph the throttle alone takes 118.5 Wh a mile, easy pedaling brings it to 94.1 and steady pedaling to 72.4. Each watt you add at the pedals is a watt the motor does not have to make, along with the losses the motor and the pack would have spent making it.

Use the gears to keep your cadence comfortable, low ones for starts and climbs, as the manual does for the first ride with "a low gear (1 or 2)", and let your effort do the saving.

Does going uphill drain the battery faster?

Yes: at 10 mph on the throttle up 4 to 10% grades, each 1,000 feet of climbing takes 200 to 278 Wh more than the same distance on level ground, or 166 to 242 with easy pedaling. Lifting the rider and the bike is 37 to 51% of the throttle figure; the motor and the pack lose the rest, a share that grows as the grade steepens.

A 180 lb rider on the 90 lb Alaska Pro is 270 lb, and raising 270 lb by 1,000 feet takes 102 Wh at the wheel.

At 10 mph up an 8% grade on the throttle the battery spends 251 Wh per 1,000 feet, so the whole 2,160 Wh would lift you about 8,602 feet with nothing kept for the flat. Descents earn no credit in the model; since going downhill costs less than riding the same distance on the level, a budget built from these rows leaves you some spare.

At 10 mph, a 180 lb rider; the last column adds 75 W of easy pedaling. The model holds the motor to a comparable motor's rated 1,000 W, so it prices the energy a climb costs; how fast the Alaska Pro holds a grade depends on a motor Freesky rates at 4,500 W peak, so no hold speed is printed.

Add the climbing to the level miles to price a hilly ride. Forty flat miles at 15 mph on the throttle take about 702 Wh, and 3,000 feet of 8% climbing adds about 753, near 1,455 Wh of the 2,160 in all. Wind, stops and starts are extra, because every mile in the model is ridden at an even pace.

Does rider weight affect range?

Extra weight costs little on level ground and much more on a climb. A heavier load adds to the tires' and the hill's share of the work and nothing to the air's, so the gap opens up on a grade.

Everyone and everything on the bike, with the bike's own 90 lb added in each row because the motor moves it as well; throttle only. The 400 lb row is Freesky's full load capacity, a figure Freesky's own guidance counts as rider and cargo.

At 300 lb instead of 180 the level 15 mph ride shrinks by 22 miles, from 123 to 101, while the 8% climb goes from 18 miles to 10. At the full 400 lb, the level 15 mph ride still covers about 88 miles, while the 8% climb drops to 7, because on a grade most of the power at the wheel goes into lifting.

Does cold weather drain the battery?

Yes, and the cost rises as the air gets colder. The 15 mph ride with easy pedaling that covers 200 miles at 77 °F covers about 148 at 32 °F. Below 32 °F the manual rules out riding, storing and charging, so read the 14 °F row as a day to leave the bike at home.

Flat pavement, a 180 lb rider. Each central figure comes from McMaster University's LG HG2 cell data, recomputed at a 0.5C discharge; the lab measured 77, 50, 32 and 14 °F, the other rows are interpolated, and the cells are assumed to sit at air temperature.

Where published cell data disagree, the brackets give the spread. The low end of each is the lowest capacity Samsung's data sheets print at that temperature when the cell is drained at one to four times its capacity an hour (the 25R and 30Q at 32 °F, the 35E at 14 °F); the high end is the most energy Casado and colleagues measured in 2025 at a gentler rate.

At freezing, three things work against you together. The cells give back about 89% of the energy they hold at 77 °F (80 to 93% across the sources), and the air is about 9% denser, by the gas law of the U.S. Standard Atmosphere.

Cold rubber is the third: the model raises rolling resistance by 0.5% for each °F below 77 °F (0.9% per °C) and lowers it at the same rate above, a rate that sits between Rothhämel's fit for a 42 mm tire and Bicycle Rolling Resistance's road-tire average; below 41 °F it holds the 41 °F value.

In 95 °F heat the model comes out ahead of its 77 °F figure, because warmer tires and thinner air save more than the cells' 1% loss.

Do fat tires cut range? Tires and riding position

On level ground the tire moves your range more than your riding position does. Bicycle Rolling Resistance's drum put ten 26 × 4.00 fat tires, the Alaska Pro's own size, between 23.2 and 42.1 W at 12 psi, 18 mph and a 94 lb load. It has not measured the CST BFT that Freesky's pictures show on this bike, so the model uses the median of the ten, a coefficient of 0.0105.

Miles from a full charge, flat pavement, a 180 lb rider. Schwalbe's Jumbo Jim LiteSkin rolled easiest of the ten and Kenda's Juggernaut Pro hardest, listed on the site at 0.01262.

Pump the tires to the manual's range, "Freesky recommends 16-20 PSI for the stock tires", which is firmer than the 12 psi on the drum. No drum measures sand, dirt or gravel; email us the route and we will price the trail ride for you.

How upright you sit matters more the faster you go. Tengattini and Bigazzi measured 90 everyday mountain-bike riders at 0.603 m² of drag area, the value this model uses for the Alaska Pro's mountain-bike frame, and 37 upright cruiser riders at 0.640 m², which would take the 20 mph throttle ride from 87 miles to 84.

Freesky's 98 to 175 miles, matched to real rides

Freesky's band, 98 to 175 miles on pedal assist, covers a wide spread of steady rides. The manual is plain about what a published range is: "The listed range and top speed of the bike are estimates, not guarantees of performance."

• 175 miles allows 12.3 Wh a mile: about 9.5 mph on the throttle, 16.0 mph with easy pedaling, or 19.0 with steady pedaling, all on flat pavement.
• 98 miles allows 22.0 Wh a mile: about 18.4 mph on the throttle, 21.4 with easy pedaling, or 23.5 with steady pedaling.

So the top of Freesky's band matches gentle rides with some pedaling, and the bottom matches throttle riding near the 20 mph default. Its dual-battery FAQ gives 120 to 200-plus miles for the same 18 + 27 Ah pair, which the model reaches at 15 mph between the throttle, 123 miles, and easy pedaling, 200.

Plan from 80% of any figure here. That is where Freesky's charging guide suggests stopping a charge when the whole range is not needed, and it leaves 20% in the pack unused. At 15 mph on the throttle, an 80% charge covers 99 miles of the full 123.

How every figure here is worked out

Holding a speed takes a steady flow of power at the wheel. The model Martin and colleagues validated on a road in 1998 puts that power in one line, for a constant speed in still air:

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

Here v is the speed, m the mass of the rider, cargo and bike together, g gravity, θ the slope angle, Crr the tires' rolling resistance (0.0105 means a drag of 1.05% of the weight on the tires), ρ the air density and CdA the drag area, a measure of how much air the rider pushes aside.

In the bracket, the first term is the tires and the hill and the second is the air; multiplied by v, the air's term grows with the cube of the speed.

Four steps separate the wheel from the battery:

1. Your pedaling reaches the rear wheel through the chain at 97.7% efficiency, Martin and colleagues' figure, and the motor makes up the rest.
2. The rear hub motor carries the whole push, turning with the wheel.
3. The motor is modeled on the published figures of a comparable motor. Bafang's 2021 OEM workbook gives its RM G0H0, a 48 V geared hub, an n0 of 510 rpm, an nT of 426 rpm, a rated 1,000 W and an efficiency of "≥ 80" percent. Read as the no-load and rated speeds, those are 40.5 and 33.8 mph on Freesky's 26.7-inch wheel; the modeled motor holds at most 29.6 mph on the flat, so no row here runs faster than 28 mph. The model takes 80% at the rated point and lets the efficiency fall at lighter loads.
4. The pack gives up a little energy inside itself, at the battery efficiency Arango, Lopez and Ceren measured on a 48 V pack.

From there, watt-hours per mile = battery watts ÷ mph, and miles = 2,160 Wh × the share of the pack's energy left at the temperature ÷ watt-hours per mile.

One ride, worked through: 15 mph on flat pavement on the throttle, a 180 lb rider. The tires take 84.9 W and the air 107.6 W, so the rear wheel needs 192.5 W.

At 15 mph the wheel turns at 189 rpm. In the motor model (0.899 N·m of torque per amp, a 0.304 Ω winding and a 1.10 A no-load current, each worked out from Bafang's published figures), the motor gives 9.7 N·m on 11.9 A at 75% efficiency, under its 80% because the load is light, and draws 255.3 W.

Counting the pack's own losses, the battery supplies 263.1 W: 17.54 Wh a mile at 15 mph, and 2,160 ÷ 17.54 is about 123 miles, or 98.5 from an 80% charge.

The benchmarks under the model, recomputed, and one filmed ride of this bike. Both halves of the model reproduce a figure their sources print, and the ride sits beside them:

Martin and colleagues' Appendix I example (a ground speed of 8.36 m/s, a 90 kg system on a 0.3% grade) and Bafang's rated point for the RM G0H0, both recomputed in the model's self-test; the ride is Ryde Kulture's "100 Mile Challenge" video, about two months old on September 25, 2026.

The filmed ride is a check on the model, not its calibration. The rider, who says "I weigh 220 lb", rode on pedal assist ("I've not been using the throttle"), was "going between 20 to 30 mph" on open stretches of paths, streets and gravel with hills, and noted that "it's been windy all day". The tally at an empty battery was "45 + 35 is 80 mi", about 27.0 Wh a mile.

The model's steady 20 mph ride at 220 lb uses 20.6 Wh a mile with easy pedaling and covers 105 miles, and 25.9 on the throttle for 83. A day of 20 to 30 mph stretches into the wind, with climbs and gravel, lands beside the steady throttle ride, and the model was not tuned to it.

Brakes and lights

Freesky fits "180MM 4-piston Hydraulic Brakes" at both wheels, to stop a 90 lb bike that can carry 400 lb. The manual warns: "Relying only on the rear brake will significantly increase your stopping distance."

Up front, the four-piston caliper and the rotor behind the fork leg.

Freesky lists an "800 Lumen LED Headlight", and on the page a turn-signal system "Integrated into the handlebars" that works "with a simple press of a button".

The headlight lit at the front, and the tail light under the end of the rack.

The LCD, in the page's words, "Displays key ride information at a glance, including 5 PAS levels, headlight status, speed, battery life, and mileage for total control." To start the bike, the manual has you switch on the battery, then "use NFC to swipe the screen, or hold the power button and then enter the password" that the manual prints.

A 120 mm fork, a 150 mm air shock and 26 × 4 tires

Freesky specifies a "120 mm Oil-Sprung Front Fork" and a "150 mm Air Rear Shock", and says of the shock that it "absorbs bumps and impacts, delivering enhanced stability, comfort, and control for a smoother ride across any terrain."

The fork above a 26 × 4 CST tire; Freesky shows it on a Blue-gray frame.

The rear shock between the frame and the linkage; Freesky lists it as a 150 mm air shock.

The tires are 26 × 4" fat tires, inflated to 16 to 20 psi per the manual, above the 12 psi in the tire table. Around them sit a Shimano 7-speed derailleur, a KMC chain, an "Upgraded 6061 Aluminum" frame and an adjustable heavy-duty aluminum kickstand.

Behind the rack: the rear hub motor, the derailleur, the kickstand and the shock above the chainstay.

The Shimano derailleur moves the chain across the seven-cog freewheel on the hub motor.

90 pounds and a 400-pound capacity

Freesky publishes 90 lb for the Alaska Pro, in its specification and again in its comparison chart, and a 400 lb load capacity.

The 400 lb covers whoever and whatever rides on the bike; the bike's own weight is outside it. Freesky's hunting-bike guide defines the term plainly: "Remember that total payload includes the rider and cargo." A 220 lb rider with 60 lb of gear on the rack and in a backpack comes to 280 lb, 120 lb inside it.

Plan the lift for more than 90 lb. The rack, the mudguards and both packs ride on the bike, so check any hitch rack, lift or stair plan against the weight you will actually carry. One reviewer, Spokes & Scenery, weighed the bike at "87.1 lb without the fenders, the rear rack, any batteries installed" and said that with them fitted it topped 100 lb.

An owner on Freesky's page wrote on July 11, 2025 that the weight "requires an above average lift kit for travel on a car or SUV".

At 76.5 inches long and 44 inches tall on Freesky's table, or 48.8 inches to the top of the bars on its drawing, the Alaska Pro needs a garage bay or a ground-floor room more than a hallway, so measure where it will live as well.

The Mercer fit test

Every review we publish holds the bike up to the same seven people, the Mercers, so every machine faces the same fit questions (meet the Mercers). Each verdict below rests on a figure Freesky publishes, the height range, the seat heights, the standover, the weight, the load capacity or the age line in the manual, or on the fit tables computed from them.

Jack and Ruth show where the Alaska Pro divides a family. At 6'1", Jack is inside Freesky's range and rides the saddle at its highest, with more knee bend than the formula asks; at 5'5", Ruth sits one inch under Freesky's range, so the bike that fits her is a different one.

Is it UL certified?

Yes: Freesky publishes a UL 2849 certificate for the Alaska Pro and a UL 2271 certificate for its 18 Ah pack. Both are TÜV SÜD America certificates, and Freesky's page labels them "UL2849 Certified by TÜV" and "UL2271 Certified by TÜV (18Ah)".

Both read September 25, 2026 from the PDFs Freesky links on the Alaska Pro page; the holder named on both is GuangZhou Yansan Science & Technology Co., Ltd.

UL 2849 is the standard for the whole electrical system: in Freesky's own summary it covers "batteries, motors, controllers, and wiring". If a landlord, a building manager or an insurer asks for the paperwork on each pack, email us and we will get it from Freesky in writing.

Has it been recalled?

No. We searched the Consumer Product Safety Commission's recall database on September 25, 2026, reading every field of a 623-record corpus built from bicycle, e-bike, battery and scooter terms and querying the title, description, product-name and manufacturer fields directly for Freesky. No record names Freesky, Yansan, the M-520 or the Alaska Pro; the three records that contain the word Alaska use it for the state.

Before its empty result was believed, the same search had to find recalls known to exist, and it did: Ancheer 1, Specialized 49, Trek 34.

The class question: 20 mph by default, 40 mph published

Settle this before you buy, because Freesky gives the Alaska Pro two speeds. Its product page says the motor reaches "up to 40 MPH in both throttle and pedal-assist modes" and its comparison chart "40MPH (Throttle & PAS)", while the product record's feature list reads "40 MPH by Pedal Assist, 20 MPH by Throttle". The FAQ further down the page reads:

All Freesky eBikes are limited to a maximum speed of 32 km/h (20 mph) by default, which complies with local e-bike regulations. If you wish to exceed this speed, you will need to obtain a license, license plates, and insurance for your eBike.

A reviewer describes that default at work. Spokes & Scenery found that at pedal assist 3 "it brings you to the full 32 km per hour", about 20 mph, and that levels 4 and 5 stayed at 32.

So there are two machines in one box: the Alaska Pro as it arrives, helping up to 20 mph, and the 40 mph machine Freesky also describes, which its own FAQ ties to a license, plates and insurance.

California Vehicle Code § 312.5(a), read on September 25, 2026, calls an electric bicycle a bicycle "equipped with fully operable pedals and an electric motor that does not exceed 750 watts of power".

The section goes on: a class 2 bicycle's motor "is not capable of providing assistance when the bicycle reaches the speed of 20 miles per hour", and a class 3 bicycle assists "only when the rider is pedaling" and "ceases to provide assistance when the bicycle reaches the speed of 28 miles per hour".

At the federal level, 15 U.S.C. § 2085(b) describes a low-speed electric bicycle as "a two- or three-wheeled vehicle with fully operable pedals and an electric motor of less than 750 watts (1 h.p.), whose maximum speed on a paved level surface, when powered solely by such a motor while ridden by an operator who weighs 170 pounds, is less than 20 mph."

Sources: § 312.5(a)(2) and (a)(3), Freesky's product page and product record, read September 25, 2026.

Get the continuous motor rating in writing. Freesky lists a "4500W Peak Brushless Motor", a peak figure. The California text reads "does not exceed 750 watts of power", the federal one "less than 750 watts", and neither tells you whether a peak or a continuous figure is meant.

Where the watt line applies to you, email us and we will get the Alaska Pro's continuous rating from Freesky in writing before you order. Our 50-state e-bike law atlas prints each state's definition, and the manual gives the same advice: "contact local or state authorities to learn more about the electric bike rules surrounding e-bike legislation near you."

Check your cover as well. The manual warns that "your insurance policies may not provide coverage for accidents involving Freeksy eBikes" and says to "contact your insurance company or agent" before you rely on them.

Where you can ride it

Off pavement, the land manager decides whether the Alaska Pro is allowed, and federal land managers start from the e-bike classes, so the 20 mph default and the watt line both count.

In the National Forests, the Forest Service's final e-bike directives, issued March 31, 2022, "provide for managing all classes of e-bikes as motor vehicles and require local-level decision-making and environmental analysis to allow use of e-bikes on non-motorized trails", according to its notice at 87 FR 41278.

Where a Ranger District has put out a motor vehicle use map, 36 CFR 261.13 bars operating a motor vehicle "other than in accordance with those designations".

For Bureau of Land Management land, 43 CFR 8340.0-5 builds the same three classes around "an electric motor of not more than 750 watts (1 h.p.)", and counts an e-bike as a non-motorized bicycle only where "the authorized officer has expressly determined" so.

Four kinds of ground, four different documents; no spec sheet settles any of them.

What a violation costs on a National Forest is set in 36 CFR 261.1b: breaking the part's prohibitions carries "imprisonment of not more than six months or a fine in accordance with the applicable provisions of 18 U.S.C. 3571 or both". Our public-land e-bike guide goes agency by agency.

On a dirt slope like this one, the land manager's rule has the last word; in this picture of Freesky's the rack and mudguards are off.

Green flags / Red flags

Green flags

• 2,160 Wh in two packs: 18 Ah on the top tube and 27 Ah in the down tube, good for a computed 123 miles at 15 mph on the throttle for a 180 lb rider.
• Either pack runs the bike: Freesky's FAQ says "The bike can operate with only one working battery", and one pack alone still covers 49 or 74 miles at 15 mph on the throttle.
• Two chargers in the box: 3 A and 2 A, so both packs charge at once, in 8–10 hours on Freesky's chart.
• An upright cockpit: the grips sit 32.6 to 35.1 inches above the crank axle, so the median rider leans 5 to 10 degrees from upright with 9 to 12 percent of their weight on the hands.
• Full suspension: a 120 mm oil-sprung fork and a 150 mm air rear shock.
• Four-piston hydraulic brakes at both wheels, on 180 mm rotors.
• Lights and turn signals: an 800-lumen headlight, a tail light and signals switched from the handlebar.
• Published UL certificates: UL 2849 for the M-520 and UL 2271 for its 18 Ah pack.
• A rack and mudguards in the box, with a 400 lb load capacity for rider and cargo.

Red flags

These are about fit: who the Alaska Pro is wrong for, and where to look instead.

• Wrong if you will be lifting it every day. At 90 lb as Freesky lists it, and over 100 lb with its packs, rack and mudguards on one reviewer's scale, steps and hitch racks may need two people; email us the stairs or the rack and we will point you to a lighter bike on our shelf.
• Wrong if you are shorter than 5'6". Freesky's range starts there, and the standover, 28.7 inches on its table and 31.5 on its drawing, leaves little room at a stop; send us your height and inseam and we will find a bike with a lower frame on our shelf.
• Wrong if you want the saddle at full leg extension and your inseam runs past 32.5 inches. That is where the 40.7-inch top of the seat meets the fit formula; find your row in the fit tables before you order.
• Wrong for short trips on flat ground. A 2,160 Wh pair is built for distance; our hub-drive picks match lighter single-motor bikes to short commutes.
• Wrong for riders under 18. The manual sets 18 as the minimum age to ride it; our 50-state law atlas lists each state's age rules, and we can point a teenager to a bike that fits them.
• Wrong if you plan to ride public roads faster than 20 mph without a license. Past 20 mph Freesky's FAQ calls for a license, plates and insurance; email us and we will suggest a bike that stays inside your state's classes.
• Wrong if you want a motor in each wheel for loose ground. The Alaska Pro drives the rear wheel only; our dual-motor guide sets out bikes that drive both.
• Wrong if you want the assist to follow how hard you push. A cadence sensor answers the cranks turning, not the force on them; our e-bike motor guide explains both kinds of sensor, and we can suggest a torque-sensing bike from our range.
• Wrong for trails that admit Class 1 bikes only. Its throttle keeps it off them; our public-land guide quotes each agency's rule, and we will look up your trail with you.

Buy it if / Buy something else if

Buy it if you want long rides from one charge, 123 miles computed at 15 mph on the throttle, with a second pack on board that Freesky says can run the bike alone.

It fits your life if you ride dirt roads, gravel, rural routes, trails open to e-bikes like this one, or your own land; you are 18 or older and 5'6" or taller, with the saddle at its 40.7-inch top if your inseam runs past 32.5 inches; and you can keep a heavy bike dry and charged at 50 to 77 °F.

For $1,899 you get a 4,500 W peak rear hub motor, 2,160 Wh in two removable packs with two chargers, full suspension, four-piston hydraulic brakes, lights and turn signals, a rear rack and mudguards. Shop Pay's sample plan on our listing is $171.40 a month for 12 months at 15% APR, $2,056.80 in total, subject to an eligibility check.

Owners on Freesky's page rated the Alaska Pro 4.9 out of 5 across 134 reviews as of September 25, 2026.

One of them, writing on July 28, 2025: "I am 220 lbs and easily get over 100 miles on a charge when using an average of 2 to 3 PAS." Another, on May 11, 2026, wrote that the two packs give "more than enough range for probably 3 or 4 hours of 20 mph riding", with pedal assist on its third level.

Buy something else if your trips are short and flat, where our hub-drive picks fit a lighter bike to the job; if you are under 5'6"; if you want a motor in each wheel for loose ground, which our dual-motor guide covers; or if your trails allow Class 1 bikes only, in which case email us the trail system and we will match a bike to its rule. Every review we have published is listed on our e-bike reviews hub.

Before you buy: the checklist

Ten checks before you spend $1,899; the first three tell you whether the Alaska Pro is yours to ride at all.

1. Check the rules where you will ride: your state's e-bike definition on roads and paths, the land manager's on trails.
2. Make sure the rider is at least 18, the manual's minimum.
3. Get the continuous motor rating from us in writing if a watt line applies where you ride.
4. Measure your inseam and find your row in the fit tables; past 32.5 inches, the saddle sits at its top.
5. Add up everyone and everything that rides on it and keep the total at or under 400 lb; the bike's own weight is not part of that sum.
6. Plan the storage and the lift for a bike one reviewer weighed at over 100 lb with its packs, rack and mudguards.
7. Ask us which battery pair your unit carries, 18 + 27 Ah or the earlier 18 + 23 Ah, and we will confirm it in writing.
8. Find your ride in the range tables, plan on 80% of it, and budget your climbing.
9. Choose a charging spot that stays dry and between 50 and 77 °F, with room for both chargers, and allow about 9 hours from empty.
10. Read the class section before you ride faster than 20 mph anywhere.

Buying it from us

Why buy the Alaska Pro from Redtail

The price on our listing is $1,899 in Black or Green and $1,999 in Camouflage, read September 25, 2026, with $2,649 and $2,699 shown as the regular prices. Our part starts the day the order ships.

Changing your mind works differently: an unopened bike still sealed in its factory packaging, requested within 72 hours of delivery, carries a 15% restocking fee plus return shipping, and canceling an order carries a 3% transaction fee. That is why we would rather answer your fit, battery and trail questions before the order goes in.

Frequently asked questions

How far can the Freesky Alaska Pro go on one charge?

Freesky publishes 98 to 175 miles on pedal assist. On our computation for a 180 lb rider on flat pavement, a full charge covers about 123 miles at 15 mph on the throttle, 87 at 20 and 200 at 15 with easy pedaling. At 10 mph up 4 to 10% grades, climbing adds 200 to 278 Wh for every 1,000 feet on the throttle; the range tables break it down.

How fast does the Freesky Alaska Pro go?

Freesky's FAQ says its bikes are limited to 20 mph by default, and one reviewer found the assist stopping at 32 km/h, about 20 mph, as the bike arrived. Freesky's page publishes 40 mph on the throttle and pedal assist, and its FAQ says going past 20 mph requires "a license, license plates, and insurance".

Is the Freesky Alaska Pro street legal, and what class is it?

By default its help stops at 20 mph, where California's class 2 throttle must stop; each definition also draws a 750 W line and Freesky lists peak output, so ask us for the continuous rating in writing. At Freesky's published 40 mph it is past every class's speed line, which is where Freesky's FAQ asks for a license, plates and insurance.

Does a dual-battery e-bike double the range?

On the Alaska Pro the second pack more than doubles it, because the packs are unequal: at 15 mph on the throttle a 180 lb rider gets about 49 miles from the 18 Ah pack alone and 123 from both. At a given speed, weight and grade, range grows with watt-hours, and 2,160 Wh is two and a half times 864 (the one-pack table).

Can the Alaska Pro run on one battery?

Yes, on Freesky's account: its dual-battery FAQ says "The bike can operate with only one working battery", with the same top speed and motor output. One pack shortens the ride: at 15 mph on the throttle, about 49 miles on the 18 Ah pack and 74 on the 27 Ah.

How do the two batteries work together?

Freesky's FAQ says the system "draws power from the batteries in a controlled way", that "No manual switching is required", and that "Each battery in the Alaska system is independent", so a failed pack can be replaced by itself. The 18 Ah pack rides up top and the 27 Ah pack below, in the down tube.

How long do the Alaska Pro batteries take to charge?

Freesky's chart gives 8–10 hours, and it ships two chargers, 3 A and 2 A, so both packs can charge at once; by division, 27 Ah at 3 A and 18 Ah at 2 A each take 9 hours. The manual asks you to charge in a dry place at 50 to 77 °F.

Can you charge both Alaska Pro batteries at the same time?

Yes. Freesky's FAQ says you can "Charge both batteries at the same time", charge them individually, or charge only one, and recommends "keeping both batteries at similar charge levels". Freesky puts two chargers in the box.

What is the real-world battery lifespan?

Freesky's battery guide of March 6, 2026 says most lithium-ion e-bike batteries last "three to five years or approximately 500 to 1,000 charge cycles", as general guidance for e-bikes, with no figure for this pack. On the Alaska Pro a worn pack can be replaced alone, since Freesky's FAQ says each battery is "independent".

How much does the Freesky Alaska Pro weigh?

90 lb, the figure Freesky publishes in its specification and comparison chart. One reviewer weighed it at over 100 lb with its packs, rack and mudguards fitted, so plan racks and lifts for that (the weight section).

What is the Alaska Pro's weight limit?

Freesky lists a 400 lb load capacity for everyone and everything the bike carries. Its hunting-bike guide says "total payload includes the rider and cargo", so the Alaska Pro's own weight is not counted in the 400.

What rider heights fit the Freesky Alaska Pro?

Freesky publishes 5'6" to 6'8" and an inseam of 27 to 35 inches. Computed for the US Army's survey bodies, the saddle reaches 109% of inseam for 80 of 100 riders at 5'6" and 44 of 100 at 5'8": a 5'8" rider with the median 32.6-inch inseam needs 40.8 inches from the ground to the saddle, against the 40.7-inch top of the post (the fit section).

Is the Freesky Alaska Pro UL certified?

Yes. Freesky links a UL 2849 certificate naming model M-520, dated November 4, 2025, and a UL 2271 certificate for the 18 Ah pack, dated September 19, 2025, both from TÜV SÜD America (the UL section).

How much is the Freesky Alaska Pro?

$1,899 in Black or Green and $1,999 in Camouflage on our store on September 25, 2026, with $2,649 and $2,699 shown as the regular prices; shipping is free within the contiguous United States.

Can I finance the Freesky Alaska Pro?

Yes: Shop Pay on our listing offered a sample plan on September 25, 2026 of $171.40 a month for 12 months at 15% APR, $2,056.80 in total, subject to an eligibility check by Affirm's lending partners. You see the plan you are offered before you pay.

What warranty does the Alaska Pro have?

If you buy from us, a fault comes to us: with photos or video and your order number, our listing says we "file and manage the claim with Freesky on your behalf" (buying it from us). Before you order, email us and we will have Freesky confirm the warranty terms for your order in writing.

Where do I find the Alaska Pro manual?

Freesky's product page links it under "Download User Manual": the PDF quoted throughout this review, covering assembly, start-up, the display, tire pressure, temperatures and the warranty.

Is Freesky legit?

Look at the record for this bike: no CPSC recall record names the brand as of September 25, 2026, Freesky publishes a UL 2849 certificate for the Alaska Pro, and its manual carries the maker's name, Yansan Technology, on the cover. The verdict says who the Alaska Pro suits.

Limitations of this review

Twenty-three things this review cannot settle, listed so you can weigh them.

1. We sell this bike. Read the red flags with the same attention as the green.
2. This is a specification-verified review. Its figures come from Freesky's published documents, statutes, our own store record, the published research the range section cites, one filmed ride, or arithmetic on this page.
3. Each range figure is for a steady ride: one speed on one grade with no wind and no stops. Stops, starts and headwinds cost more, and a tailwind less.
4. Bafang's figures stand in for Freesky's motor. Freesky gives peak output, 4,500 W, and 170 N·m; the model uses Bafang's published figures for a 1,000 W 48 V geared hub, reading its n0 and nT as the no-load and rated speeds, 40.5 and 33.8 mph on the 26.7-inch wheel. Freesky's documents read here do not say whether the hub is geared or direct drive. At 82% efficiency in place of Bafang's 80% floor the 15 mph throttle figure moves from 123 miles to 131; on Bafang's 750 W version it is 120.
5. One filmed ride checks this model, loosely. The physics reproduces Martin and colleagues' worked example and the motor reproduces Bafang's 80% at the rated point. The one ride of this model to an empty battery found in a search of YouTube, 80 miles at 220 lb on a windy day mixing 20 to 30 mph stretches, used about 27.0 Wh a mile, near the model's steady 20 mph throttle ride at that weight, 25.9; a mixed ride is not a steady one, so it checks the scale, not each cell. No measured hub-motor map was available to check the motor model at light loads.
6. The two packs are treated as one 2,160 Wh store. Freesky's FAQ says the system draws "in a controlled way" with no switching; the documents read here do not say whether the packs discharge together or one after the other, and no full-charge figure on this page depends on it.
7. Every figure assumes Freesky's 2,160 Wh. The documents read here do not say how much of the packs the battery management releases; on one measured pedelec, researchers at KIT found 75% used in a standard range test.
8. Units differ by production batch. Freesky's FAQ says an Alaska carries an 18 + 23 Ah pair or an 18 + 27 Ah pair "Depending on production batch and configuration"; this page uses the 45 Ah pair the product page lists, and on the 41 Ah pair each full-charge figure is about 91% as long.
9. The tire coefficient is the median of ten 26 × 4.00 fat tires at 12 psi, a stand-in for the CST BFT the Alaska Pro wears, and the tire table brackets it with the lowest and highest of the ten.
10. The cold figures rest on one cell's laboratory data. Freesky's page does not name the cells, so the central line uses McMaster University's measured LG HG2 cell, bracketed by other published cell data, with the cells assumed to be at air temperature.
11. The model uses Freesky's 90 lb. One reviewer weighed the bike at 87.1 lb without its packs, rack and mudguards and over 100 lb with them; at 100 lb the level 15 mph throttle figure is 121 miles in place of 123 and the 8% climb 17 in place of 18. The product record's variant weight field carries 108 lb, which this review does not use.
12. Where Freesky's documents differ, this review follows the product page read on September 25, 2026. Freesky's September 12, 2025 post gives a 1968Wh pair, 90–160+ miles and an "Official 2500W peak motor"; its November 24, 2025 holiday guide "Peak 3000W brushless, 160Nm torque"; its May 18, 2026 tire guide a "4000W peak motor and 160Nm torque" with the 45 Ah pair; and its August 14, 2026 torque explainer 160 N·m. On request we will get any of these confirmed by Freesky in writing.
13. Smaller rows differ the same way. The page specifies a thumb throttle while the manual describes "rotating the throttle backward toward the rider". The page gives 40 mph on the throttle and pedal assist, while the record's feature list reads "20 MPH by Throttle". No range figure depends on these rows.
14. The owner reviews span versions. The 134 reviews on Freesky's page run from 2022 to September 2026, across the battery and motor versions item 12 lists; the owners quoted here wrote in 2025 and 2026.
15. The paperwork for the 27 Ah pack. The UL 2271 certificate Freesky links names the 18 Ah pack, FP4818R0; the documents read for this review carry no certificate number for the 27 Ah pack, and we will ask Freesky for it on request.
16. Trail access is set locally. Your land manager's rule decides, it can change, and neighboring systems differ; this page does not replace it.
17. The recall search covers the CPSC's US database under the names listed; a recall filed under another company name would need that name searched.
18. Stock and price were read on September 25, 2026, and both can change.
19. The range model uses the 26.7-inch wheel Freesky lists. On Freesky's drawing, scaled by its wheelbase, the tires measure 29.1 inches across (the drawing's wheel-diameter line runs a little past each tire, to 29.6); on the measured wheel the level 15 mph throttle figure is 121 miles in place of 123 and the 8% climb 17 in place of 18.
20. The fit figures use the US Army's ANSUR II bodies: 6,068 soldiers aged 17 to 58, measured in 2010 to 2012, who are not the US public, so your own inseam decides your row.
21. The cockpit is the one in Freesky's drawing. The crank-axle height, the seatpost and the grips are measured on it, and the point where your sit bones rest on the saddle is bracketed from the saddle's shape; where the drawing and the Size & Fit table disagree, the model keeps the table's seat range and standover.
22. The hand figure is a ceiling with a relaxed back. On a real ride your back and arms carry part of it, and we found no study that measures the hand load on an upright bike.
23. The 109% formula is a starting point. In 19 trained cyclists it put 55 to 65% inside the 25-to-35-degree knee range and the heel check put 70%, so the knee range and the heel check set the saddle.

The bottom line

For $1,899, the Alaska Pro puts a 4,500 W peak rear hub motor and 2,160 Wh in two removable packs on a full-suspension fat-tire frame, with four-piston hydraulic brakes, lights and turn signals, a rack, mudguards and two chargers.

On level pavement a 180 lb rider gets about 123 miles at 15 mph on the throttle and 200 with easy pedaling, and either pack alone still runs the bike, for 49 or 74 miles at 15 mph on the throttle.

It suits long rides on dirt roads, gravel, rural routes and your own land, for riders 18 and over from 5'6" up who can store and lift a bike of 90 lb or more; past a 32.5-inch inseam the saddle rides at its top. With Shop Pay on our listing that is $171.40 a month for 12 months at 15% APR, $2,056.80 in total, subject to an eligibility check.

Before you pay, settle the class: the bike is limited to 20 mph by default, Freesky publishes 40, and on Freesky's own account anything faster needs a license, plates and insurance. Tell us where you will ride before you order, and we will get Freesky's continuous motor rating in writing if a watt line applies.

Source register

Each document this review relies on, and what it supports.

T1 is the record itself, read from the party that issued it: a statute, a federal regulation or notice, a certificate, the maker's own product page, record and manual, our own store record.

T2 is a party's own publication about its product or its measurements: the maker's guides and posts, the motor maker's workbook, the research groups' and laboratories' published measurements. T3 is an independent party's own published observation of this bike: a reviewer's filmed ride and scale reading.

Expiry conditions

Re-read this page if Freesky changes the Alaska Pro's price, specification, battery pair, range band, 20 mph default, Size & Fit table or geometry drawing on its product page; if Freesky answers our written questions on the continuous motor rating, the 27 Ah pack's certificate or the battery pair shipping now; or if the stock, the price or the Shop Pay terms change on our store.

Re-read it as well if a recall is published naming Freesky or Yansan Technology. Verified September 25, 2026.

References

The full bibliographic record for each document cited above, with the date it was retrieved.

1. FREESKY, Alaska Pro M-520 — product page (Technical Specification, Size & Fit, Geometry, More Features, comparison chart, FAQ, customer reviews, as rendered). Retrieved September 25, 2026. https://www.freeskycycle.com/products/alaska-pro-m-520
2. FREESKY, Alaska Pro M-520 — product record, body_html feature list, variant price, compare-at price, SKU, weight field and publication date. Retrieved September 25, 2026. https://www.freeskycycle.com/products/alaska-pro-m-520.json
3. FREESKY / YANSAN Technology Co., Ltd., 26" Alaska Pro M-520 Electric Bike instruction manual: Your First Ride, What's in the Box, Start-Up Procedure, Tire Inflation, safety instructions, Bike Performance Disclaimer, Warranty. Retrieved September 25, 2026. https://cdn.shopify.com/s/files/1/0605/5188/9131/files/M-520_Instruction_English.pdf
4. TÜV SÜD America, Inc., Certificate No. U14 128702 0012 Rev. 00, UL 2849:2020/R:2022-12, Electrical Systems for E-Bikes, brand FREESKY, model M-520, dated November 4, 2025. Retrieved September 25, 2026. https://cdn.shopify.com/s/files/1/0605/5188/9131/files/UL2849-Alaska-Pro-M520.pdf
5. TÜV SÜD America, Inc., Certificate No. U10 128702 0009 Rev. 00, UL 2271:2018, Batteries (Rechargeable Li-ion Battery), model FP4818R0, 48.1 V, 18 Ah, dated September 19, 2025. Retrieved September 25, 2026. https://cdn.shopify.com/s/files/1/0605/5188/9131/files/UL2271-Alaska-Pro-M520-18Ah.pdf
6. FREESKY, FREESKY Alaska Dual Battery FAQ: How the System Works, Range Explained & Battery Questions Answered (June 10, 2026). Retrieved September 25, 2026. https://www.freeskycycle.com/blogs/news/freesky-alaska-dual-battery-faq-how-the-system-works-range-explained-battery-questions-answered
7. California Legislative Information, California Vehicle Code § 312.5, subdivisions (a), (a)(2) and (a)(3). Retrieved September 25, 2026. https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=VEH&sectionNum=312.5.
8. US Government Publishing Office, 15 U.S.C. § 2085 — Low-speed electric bicycles, subsection (b). Retrieved September 25, 2026. https://www.govinfo.gov/content/pkg/USCODE-2024-title15/html/USCODE-2024-title15-chap47-sec2085.htm
9. Bureau of Land Management, 43 CFR § 8340.0-5, paragraphs (a)(5) and (j) (85 FR 69223, Nov. 2, 2020). Retrieved September 25, 2026. https://www.ecfr.gov/current/title-43/subtitle-B/chapter-II/subchapter-H/part-8340
10. Forest Service, US Department of Agriculture, 36 CFR § 261.13 — Motor vehicle use. Retrieved September 25, 2026. https://www.ecfr.gov/current/title-36/chapter-II/subchapter-B/part-261/subpart-A/section-261.13
11. Forest Service, US Department of Agriculture, 36 CFR § 261.1b — Penalty (89 FR 92815, Nov. 25, 2024). Retrieved September 22, 2026. https://www.ecfr.gov/current/title-36/chapter-II/subchapter-B/part-261/subpart-A/section-261.1b
12. US Forest Service, Directive Publication Notice, 87 FR 41278 (July 12, 2022), recording the final e-bike directives issued March 31, 2022. Retrieved September 24, 2026. https://www.federalregister.gov/documents/2022/07/12/2022-14777/directive-publication-notice
13. US Consumer Product Safety Commission, Recall database, full-field search across a 623-record corpus, controls Ancheer / Specialized / Trek, direct title, description, product-name and manufacturer queries for Freesky, and a name screen for Yansan, the M-520 and the Alaska Pro. Retrieved September 25, 2026. https://www.saferproducts.gov/
14. Redtail eBikes, Shipping policy. Retrieved September 25, 2026. https://redtailebikes.com/policies/shipping-policy
15. Redtail eBikes, Refund policy (48-hour damage window, manufacturer-warranty coordination, change-of-mind and cancellation terms). Retrieved September 25, 2026. https://redtailebikes.com/policies/refund-policy
16. Redtail eBikes, Freesky Alaska Pro M-520 storefront record and Shop Pay terms (price, compare-at price, availability by colorway, sample plans). Retrieved September 25, 2026. https://redtailebikes.com/products/freesky-alaska-pro-m-520
17. Affirm, Affirm's lending partners (the lenders behind Shop Pay Installments, as our listing names them). Retrieved September 25, 2026. https://www.affirm.com/lenders
18. FREESKY, Best Hunting E-Bikes: Which FREESKY Electric Bike Is Right for Your Outdoor Adventure? (September 8, 2026), the payload paragraph and the Alaska Pro section. Retrieved September 25, 2026. https://www.freeskycycle.com/blogs/news/best-hunting-e-bikes-which-freesky-electric-bike-is-right-for-your-outdoor-adventure
19. FREESKY, Summer High-Temperature Charging Guide: How to Charge Your eBike Safely in Hot Weather (June 12, 2026). Retrieved September 25, 2026. https://www.freeskycycle.com/blogs/news/summer-high-temperature-charging-guide-how-to-charge-your-ebike-safely-in-hot-weather
20. FREESKY, 7 Signs Your E-Bike Battery Needs Replacement: Lifespan, Warning Signs and Solutions (March 6, 2026). Retrieved September 25, 2026. https://www.freeskycycle.com/blogs/news/7-signs-your-e-bike-battery-needs-replacement-lifespan-warning-signs-and-solutions
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