Ridstar Q20 Pro 2026: 11 Fire Reports, No Recall

A moped-style frame on 20 × 4.0 fat tires · two 52 V 20 Ah packs, 40 Ah in all · two 1000 W motors that Ridstar sells as "2000W" · 34 mph on ridstar.com, "28+++ mph" on ridstar.net, "37MPH" on its own infographic · 75 miles on the throttle, 180 in assist mode, both its figures · a CPSC fire warning that names this model · no recall · maker figures read October 12, 2026 · $1,574.35 on our store, open for orders on October 14, 2026

Quick Answer — The Consumer Product Safety Commission names the Ridstar Q20 Pro in its March 19, 2026 warning for battery and wiring fires, counts 11 reports of fire, and urges owners to "remove the battery from the e-bike immediately." On Ridstar's two-pack figure a 180 lb rider computes to 99 miles at 15 mph on the throttle, and ours is $1,574.35.

That figure assumes an 88 lb bike on level pavement and Ridstar's two packs, 2,080 Wh in all, and the range section shows you the conditions behind each figure. Our listing describes one 1,040 Wh pack, so email us before you order and we will tell you in writing which pack ships.

No recall offers a remedy, and the manufacturer "has refused to agree to an acceptable recall," the Commission reports. If you already own one, the Commission's instructions come first, before anything else you do with the bike.

If you want the same kind of bike within the 750 W limit that 44 of the 51 state rows in our census set, our fat-tire buying guide lists the bikes we sell in that use, with the motor each maker prints.

What this review covers

The CPSC warnings · The specification · Which Q20 · Fit · Motor · Battery · Range · Brakes · Suspension and tires · Weight and load · The Mercer fit test · UL · Recalls · The lawsuits · Class · Where to ride · Green and red flags · Verdict · Checklist · Buying it from us · FAQ · Limitations · Bottom line · References

How we verified this Ridstar Q20 Pro review

Every Q20 Pro figure was read on October 12, 2026 from Ridstar's Q20Pro page on ridstar.com and its product record, and from the ridstar.net record as it stood on August 26, 2026. The two CPSC warnings were read word for word on October 12, 2026, and the prices, stock and terms on our store and Ridstar's US store on October 14, 2026. Range and fit are computed from those inputs; each section names its sources.

This is a specification-verified review: each figure checked against Ridstar's pages and recomputed where arithmetic applies. Every spec figure is the maker's own claim, a sole-publisher source with no independent measurement. Where the maker's pages disagree, we print every figure with its page and date; where our listing differs from the maker, the page follows the maker. Limitations records both.

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

What the CPSC told Q20 Pro owners

The Commission's March 19, 2026 warning names the Q20 Pro and urges owners to remove the battery and dispose of it. Its June 25, 2026 warning names the Q20 and the Q20 Lite, and does not name the Q20 Pro. Neither warning is a recall, and neither offers a refund, a repair or a replacement.

Both rows as the Commission printed them, read October 12, 2026. Sold-at lines: 26-337 names Amazon.com, Ridstar.net and Walmart.com.

On the first warning, the Commission's own words are the instruction: "CPSC urges consumers to remove the battery from the e-bike immediately and dispose of the battery following local hazardous waste disposal procedures. Do not sell or give away these hazardous batteries." The company's position is printed in the same release: the manufacturer, Huizhou Xingqishi Sporting Goods Co., Ltd., "has refused to agree to an acceptable recall."

The Commission says remove the battery. The first warning's instruction is to remove the battery from the e-bike immediately, dispose of it under local hazardous waste rules, and not sell or give it away. That applies to any Q20 Pro you own, wherever you bought it.

Which bikes the warnings name

The first warning names the model, and the Commission describes the machine too: "The e-bikes are black, and the brand name Ridstar is printed on the battery. The model number Q20 or Q20 Pro may be located on the purchase receipt." Check the receipt. If it says Q20 Pro, the first warning applies to your bike.

The second warning is about the front wheel, and it does not name the Q20 Pro. Its own receipt line reads: "The model number Q20 or Q20 Lite is printed on the purchase receipt." The Commission does not say in that warning whether a Q20 Pro has the same front-wheel fault, so the review does not say it does. If you own one, ask the seller in writing before you ride.

If you own one

Remove the battery, take it to a hazardous waste collection point, and do not sell or give the bike or the battery away. Both releases add the same instruction for the battery: "Do not throw this lithium-ion battery or device in the trash, the general recycling stream (e.g., street-level or curbside recycling bins) or used battery recycling boxes found at various retail and home improvement stores."

A new battery does not answer the warning. Ridstar's own store still lists battery packs for the Q20 family, and a variant labeled "US / Q20 Pro" showed as available on ridstar.net on October 12, 2026. Neither warning mentions a replacement battery, so the Commission's instruction to dispose of the battery does not tell you that a new pack is safe.

The maker's position

The Commission prints the manufacturer's objection to the press release: "The company objects to this press release." Ridstar's own pages limit service to its own buyers. The Q20 Pro page says, under its warranty heading, that "The Ridstar Warranty Policy is only available to customers ordering from ridstar.com.

"Customers ordering Ebikes from other websites will not be able to receive warranty support on this website." The ridstar.net statement says the same of its store. Our warranty answer sets out what that means for a bike you buy from us.

The Q20 Pro's specification, figure by figure

Ridstar prints three top speeds, one torque figure printed on two of its pages, two climbing angles and four warranty statements for this one machine, and the table prints every one of them. The first column is what ridstar.com's product page says today. The second is ridstar.net's record from August 2026, and the third is what the maker's own infographic says.

Ridstar's own studio photograph, gallery image 11 of its Q20Pro record. The spare mirrors at the top right are an accessory laid beside the bike.

Read October 12, 2026 from the ridstar.com page, its record and the ridstar.net record of August 26, 2026; the infographics are the maker's gallery images 1 and 2 on its page. Weight is a catalog field, and it is not a bike weight.

The maker's own pages also disagree on the Q20 Pro's identity. Its page title calls it a "Dual Battery/Motor" bike, and its product heading calls it a "Fat Tire Electric Bicycle". The maker's page names no class for it.

Our product page is the other source you will meet, and it differs from the maker in one figure that matters. Our listing describes a single 52 V 20 Ah pack and 1,040 Wh. Ridstar's page describes two packs. This review uses the maker's figure, 2,080 Wh, and says in the battery section why the two numbers differ.

Which Q20 is this? The middle of three

By the titles Ridstar gives its bikes, the Q20 Lite is 1000 W, the Q20 1500W is 1500 W, and the Q20 Pro is 2000 W on two motors. The family's shared frame is the moped-style machine in the photographs: a long bench saddle, a round headlight, and a battery in the frame.

Ridstar's studio side view, gallery image 6. The photograph prints no dimension, so it is not a measurement.

The Q20 1500W is the bike in the middle, and our review of it reads its own maker's figures in the same way. The two reviews differ in what matters here. The 1500 W bike carries one 48 V 20 Ah pack, and the Q20 Pro carries two 52 V 20 Ah packs and two motors, for a rated system of 2,000 W on the maker's page.

Our listings for the other two bikes in the family are the Q20 1500W and the Q20 Lite. Both are named in the CPSC warnings, so they appear here as reporting only.

The difference is not only in the watts. The Q20 Pro's 34 mph top speed on the maker's page sits above the 28 to 33 mph the 1500 W bike prints, and its 180 mile assist-mode range is more than double that bike's 75 miles. Read the range section before you read the numbers on either page.

The third bike in the family, 1000 W on one 720 Wh pack and named in the crash warning, has its own Ridstar Q20 Lite review. Outside the family, our Q30 Pro review sets this bike beside the Q30 Pro, which also carries two motors and two packs and which neither warning names. Our reviews of the Q50, the folding H26 Pro, the Q30 Lite and the step-through MN26 read each of those bikes from Ridstar's own pages.

For the maker behind both warnings, read our Ridstar profile; the e-bike reviews index lists the other makers we review.

Who the Q20 Pro fits: Ridstar's 5'4" to 6'2" window

By the standard saddle formula, if you are a median 5'10" rider your saddle top sits 36.8 inches above the pedal axle, and at a median 6'1" it sits 38.8 inches above.

Ridstar publishes a rider-height window of 5'4" to 6'2" on its spec block and 5'4" to 6'4" on its product card. The window says nothing about inseam, and two riders of the same height can differ in inseam by about three inches.

Ridstar's studio front view from its gallery. The record prints no geometry, so the photograph is not a measurement.

Get your own figure in three steps:

1. Measure your inseam in stocking feet against a wall, with a book between your legs at the crotch.
2. Find your height in the saddle table and read the saddle top to the pedal axle for your inseam band.
3. Set the saddle so the heel rests on the pedal at its lowest point with your leg straight, then bend the knee to the 25 to 35 degree target in the setup subsection.

The Q20 Pro publishes no geometry at all. There is no seat-height range, no crank length, no standover, no wheelbase, no reach and no handlebar height on either store, so the fit section can compute the formula and the window and nothing more. Each subsection says what it can and cannot tell you.

What seat height does the Ridstar Q20 Pro need?

The formula sets the saddle top at 109% of inseam from the pedal axle, the figure Peveler et al. (2005) set against the heel method.

Ferrer-Roca et al. (2012) give 106% to 109% of inseam as the recommended range and 108.6% to 110.4% from their equation, and the table prints 106% and 110.4%, the two ends of those ranges. The table takes the inseam bands from the US Army's ANSUR II survey of 6,068 bodies, and every row is printed beside the others.

The Q20 Pro's saddle range is not published, so the table tells you where the formula puts your saddle, and not whether the seat post reaches it.

The formula saddle table. Inseam bands are the middle 90% of ANSUR II bodies at each height (min 30 per band). The 109% column is Peveler et al.'s formula figure, and the 106% and 110.4% columns are the ends of the Ferrer-Roca ranges. No crank length is published, so LeMond's 88.3% column cannot be computed and is omitted.

Standover: feet down at a stop

Ridstar publishes no standover height, so this subsection cannot compute the clearance over the top tube. The frame's standover is not published either, and neither is the reach. Read the standover on the bike you are buying before you decide. If the seller cannot give it, the standover is a fact the record does not contain.

How tall do you need to be for the Ridstar Q20 Pro?

The cockpit lean needs a handlebar position and a reach, and Ridstar publishes no figure for either, so the record cannot tell you whether you would reach the grips without leaning at 5'4", or sit cramped at 6'4".

Both windows are printed in the specification table. For the reach itself, sit on the bike you are considering, at rest, before you decide.

Hand load and the wrists

Hand load depends on where your hands sit, and the grip position is not published. The only measured reference this page can cite is 15% of body weight carried on the handlebar stem, from Carahalios (2015) on ten road racers with their hands on the hoods of a road bike.

That is a ceiling for a racer in a forward position and not a figure for the Q20 Pro's upright riding position. The model does not compute a Q20 Pro hand load, and the review does not print one.

What size is the Ridstar Q20 Pro?

Set the saddle with the heel check first. Put your heel on the pedal at its lowest point with the crank in line with the seat tube, and straighten the leg. If your hips rock side to side on the saddle, or the leg will not straighten with the heel on the pedal, the saddle is too high.

Then set the ball of the foot on the pedal and bend the knee to the 25 to 35 degree target, which Peveler, Pounders and Bishop (2007) and Ferrer-Roca et al. (2012) studies bracket. Two riders of the same height can need different saddle heights, so treat the formula as your starting point.

What height does the Ridstar Q20 Pro suit?

The model takes the inseam bands from ANSUR II, and prints the saddle top above the pedal axle at 109 percent, 106 percent and 110.4 percent of each inseam. Its worked example takes a 68 inch rider with a 32.6 inch inseam, the model's value for that height, and computes the 109% saddle at 35.6 inches, the 106% saddle at 34.6 inches and the 110.4% saddle at 36.0 inches above the pedal axle.

For a 5'10" rider the median inseam is 33.8 inches, and the saddle top sits 36.8 inches above the pedal axle. The validation is printed in full. The model reproduces the 109% figure against the 109.2 ± 0.9% that Peveler et al. (2005) report.

Ridstar publishes no saddle range, so the model has no maker figure to check its output against. That gap is a fact about the record, and Limitations lists it.

The Mercer fit test

Seven members of the Mercer family are set against the Q20 Pro so the fit answers compare from page to page. Each row reads Ridstar's window, the saddle table, the CPSC warning or the law. The verdicts use only the published figures and the age law, and the people are archetypes rather than testers.

The people are the Mercer family, the same archetypes we hold every reviewed bike against. Heights and ages are theirs; the saddle figures are the model's at each height.

Every adult in the family fits Ridstar's window, and none of them should ride a Q20 Pro while the Commission's instruction stands. The sharpest line runs through the two youngest. Cole is 16 and Ivy is 12. Ridstar's own pages print a 2,000 W system and 34 mph, and both figures sit above the class limits in the class section. Age does not make that machine a teenager's bike.

A two-motor system on Ridstar's figures

Ridstar prints two 1000 W motors and a 2000 W system, with 90 N·m per motor, and it prints no peak, continuous or nominal split for either. The rating matters for the law, because 44 of the 51 state definitions in our census set a motor limb of 750 watts, and the record offers only the total.

A crop of Ridstar's photograph (gallery image 11). A dark hub sits at the center of the wheel; the record does not say whether it is a motor.

The maker's infographic promises "0-3 Seconds up to 34mph" and calls the machine "POWERFUL BRUSHLESS MOTOR 2000W". Those are marketing figures, and this review uses them only as the maker's claims. A reader can check acceleration on a test ride, and the review cannot check it from the record.

The range model treats the two motors as one system at 52 V, rated at 2,000 W, and it runs on the published curve of a comparable Bafang motor from its 2021 workbook. The comparable's efficiency curve is the source of most of the range model's uncertainty, and the range section prints the figures with and without it.

A 52 V pack in two halves: 2,080 Wh

Ridstar's page prints two 52 V 20 Ah packs, 40 Ah in all, which is 2,080 Wh by arithmetic from the maker's own volts and amp-hours. Our product page prints one 20 Ah pack and 1,040 Wh. The two figures cannot both describe the bike the buyer receives, so this review prints the maker's figure and flags the listing.

Ridstar's studio rear view, gallery image 10.

Ridstar's page calls the design "a large capacity and safe dual battery design", and ridstar.net calls its batteries "UL-certified 52V 20Ah batteries, totaling 40Ah". The UL claim is in the UL section, with no certificate or file number attached to it.

The model uses 2,080 Wh for every range figure in this review. At 15 mph on the throttle, a 180 lb rider on an 88 lb bike draws about 21 Wh a mile from the pack, so a full pack goes near 99 miles on flat pavement. If the bike you buy carries one 20 Ah pack, which is what our listing says, the figures in the range section roughly halve.

The maker's charge time is 4 to 6 hours, and its page prints no charger rating, so this review does not compute a charge cost. The June 2025 UK safety report on Ridstar's "Q20-Plus, Q20-Mini, E26 Pro and Chargers" names a charger with poor soldering. That report does not name the Q20 Pro, and this review does not apply it to the bike.

Range: how far 2,080 Wh carries the Q20 Pro

On level pavement with a 180 lb rider on an 88 lb bike, a full pack carries the Q20 Pro a computed 99 miles at 15 mph on the throttle, 76 miles at 20 mph, and 134 miles at 15 mph with easy pedaling. Each 1,000 feet of climbing on the throttle costs the pack about 125 to 138 Wh, depending on the grade, so a steep road shortens your ride.

Ridstar's studio photograph, gallery image 7. It carries no range figure; the range here is computed.

Get your own figure in three steps:

1. Find your cruising speed and how hard you pedal in the speed tables.
2. Add the climb cost of your route from the hill table, about 125 to 138 Wh for each 1,000 feet on the throttle.
3. Correct for your weight with cargo and the air temperature, then plan on the planning column, which keeps a quarter of the pack in reserve.

Every number in this section is computed by one steady-state model. Its inputs are Ridstar's own figures, a comparable motor's published curve, measured fat-tire rolling resistance and a cycling-power model, and the formula subsection walks one ride through it so you can check the arithmetic yourself.

How many miles can the Ridstar Q20 Pro go?

Speed is the largest term in your range. The first table pairs the throttle with the planning column, and the second shows what your steady pedaling adds at each speed. Both assume level pavement, a 180 lb rider on an 88 lb bike and 77 °F.

Miles on a full 2,080 Wh pack, flat pavement, 180 lb rider, 88 lb bike (the catalog weight), 77 °F, tires at the median rolling resistance of ten fat-tire tests. The last column keeps 25% of the pack in reserve, the share left after Schmitt, Decker and Doppelbauer (2019) measured a pedelec using 75% of its nominal pack. Ridstar publishes no reserve for this model.

Miles on a full pack at each effort. "Easy pedaling" adds 75 W of rider power and "steady pedaling" 150 W, both steady on the flat. Throttle-only is the first column of the table above.

What gears does the Ridstar Q20 Pro have?

Ridstar's ridstar.net record says the Q20 Pro has a Shimano 7-speed gear system, and the record does not say which wheel or motor the gears act on. The model treats the gears as acting on the pedals only: they change your cadence and the effort your legs add, and they leave the motor's load alone.

That is an assumption the record does not settle, and Limitations lists it. The table below therefore shows the effort a ride needs, and it is not a gear chart.

Watt-hours a mile from the pack on the flat and on two grades, at three efforts. Each row is one ride. The 12 mph rows show how a grade changes the cost of a slow ride.

Hills and the pack

Each foot you climb draws on the pack at a near-steady rate. Throttle-only climbing takes about 125 Wh per 1,000 feet at a 4% grade, 129 at 6%, 134 at 8% and 138 at 10%. The miles per charge fall faster than the grade rises, because a steeper road also slows you down.

Full-pack miles by grade at a steady 10 mph, throttle and easy pedaling. The grades run from 2% to 15%.

How much range does the Ridstar Q20 Pro have?

For a 180 lb rider a full pack computes to 99 miles at 15 mph on the throttle, and your weight with cargo moves that figure. On the flat at 15 mph, moving from a 100 lb rider to a 260 lb rider on the throttle takes the pack from 109 miles to 91 miles. The climb at 8% shows the larger drop, from 40 miles to 22 miles at 10 mph.

Rider plus load, 88 lb catalog weight, throttle only. The top of the range is 260 lb: Ridstar prints no maximum load for this model, so the table stops at 260 lb, the top of the rider range the model prices.

Cold and range

The cold table uses the cell data for a representative 18650 lithium cell. Ridstar names no cell for the Q20 Pro, so the bracket below 50 °F is wide. If you ride at 32 °F, the model gives 81 miles, with the range from 72 to 85 miles. At 14 °F it gives 73 miles, with a range from 36 to 74.

Air temperature, the pack's energy against 77 °F, and the 15 mph flat range on the throttle. Brackets are the spread across the cell data read. Below freezing the sources disagree most, so the brackets widen.

Tires and seating position

Tires move your range a little. The model uses the median rolling resistance of ten fat-tire tests on a drum (0.0105). It brackets that with the lowest of the ten (0.0070) and the highest of the ten, a knobby Kenda Juggernaut Pro (0.0126). The Q20 Pro's own tires were not measured, so the bracket covers the range the drum recorded.

The position is the other term. The model uses 0.640 m² for the frontal area of an upright cruiser, from Tengattini and Bigazzi's (2018) measurements for upright cruisers. The Q20 Pro's own riding position is not published. If you sit lower or lean forward, that figure falls; the model keeps it fixed for every rider.

Rolling resistance as the drum measured it, with 15 mph and 20 mph flat throttle ranges for a 180 lb rider on an 88 lb bike.

What range does the Ridstar Q20 Pro have?

Ridstar's throttle figure of 75 miles is a steady ride of about 20 mph on the throttle alone, and its assist figure of 180 miles is a crawl on the throttle or a steady pedal of about 12 to 16 mph. Those are the rides the maker's numbers require under the same rider and bike.

Ridstar does not print the speed or effort behind either figure, so read each claim as a ride you would have to match, and never as a promise.

The two figures, read through the model at 2,080 Wh, a 180 lb rider and an 88 lb bike:

• 75 miles, throttle: 27.7 Wh a mile. Reached at 20.2 mph on the throttle alone, 22.5 mph with 75 W of pedaling, or 24.3 mph with 150 W.
• 180 miles, assist mode: 11.6 Wh a mile. Reached at 5.0 mph on the throttle alone, 12.2 mph with 75 W of pedaling, or 15.8 mph with 150 W.

The assist figure is therefore a pedal figure. Read the reach of the pack against your own pedaling, and set the headline aside.

The formula behind the range tables

The power at the wheel is the rolling resistance, plus the climb, plus the aerodynamic drag, and the battery and motor losses are added on top. The model uses the cycling-power form of Martin et al. (1998): power equals speed times the sum of the rolling term, the gravity term and the drag term, divided through the drivetrain, motor and battery efficiencies.

The inputs, each with its source. A number with no row here does not enter the model.

Sources are in the references. Each row is a published input, a comparable with its bracket, or a constant, and each is read in the model's own provenance block.

One ride, worked through step by step.

At 15 mph flat on the throttle, for a 180 lb rider on an 88 lb bike: the rolling term takes 84 W, the drag takes 114 W, and the wheel receives 198 W. The motor runs at about 65% efficiency at that speed, so the battery supplies 306 W, and the battery's own losses at 97% mean the cells give up 315.5 W.

At 21.0 Wh a mile, 2,080 Wh carries the bike 98.9 miles, and the planning figure is 74.2 miles.

The validation is printed in full. The model reproduces Martin et al.'s Appendix I values, 45.7 W for the rolling and potential terms and 158.8 W for the aerodynamic term, to the printed digit.

Its motor efficiency is read from the comparable curve at each speed, 65% at 15 mph on the throttle, and the 80% that Bafang's workbook gives is the rated-point floor, which the sensitivity cases below test. No measured ride is used to check the output, which is the gap Limitations names.

Two sensitivity cases show how far the comparable curve moves the answer. Held to 750 watts rated, the 15 mph throttle ride reads 117 miles instead of 99, and the 8% climb at 10 mph reads 24 miles instead of 29. At 82% motor efficiency the 15 mph ride reads 122 miles. Both are computed from the same inputs, and neither is a measurement.

Brakes, lights and the front wheel

The front-wheel warning names the Q20 and the Q20 Lite and does not name the Q20 Pro. The maker's own infographics do claim dual hydraulic disc brakes, and owner accounts on Reddit describe front-wheel and rim trouble on this model.

Ridstar's gallery shows "Dual Hydraulic Disc Brakes" on an infographic, under the words "Super Bright Headlight", "Rearview Mirror" and "Front & Rear Shock Absorption". Those are the maker's marketing claims. The record does not give a brake maker or a pad or rotor size, so the review does not state either.

The owner accounts are individual reports, quoted with their date and link. On August 25, 2025, an owner who hit a curb wrote that "my front wheel makes a scraping noise, whistles, and the axle wobbles a bit." On September 3, 2025, another asked whether anyone had the problem with "the both rims its cracked."

On August 2, 2026, a third asked for "cheap brake replacements for my Q20 pro." These are three people's accounts, not a count, and the review does not total them.

What you can check before a ride: the front axle and its quick-release or nut, the spokes and rims on both wheels, and the brake pads and rotors. If you own a Q20 Pro, ask the seller in writing whether its front wheel has the same fault, because the Commission's front-wheel warning concerns the Q20 and Q20 Lite and tells owners to stop using those models.

Suspension and tires

Ridstar's infographic claims front and rear shock absorption, our own listing says dual suspension, and the maker's record prints the tires as 20 × 4.0. A 20 × 4.0 fat tire is wide and low-pressure, which sets how much of the pack the rolling resistance takes, and the tire bracket prices that.

A crop of gallery image 10. The record prints no travel figure for either suspension.

The suspension figures are the maker's. The record gives no travel, no spring rate and no damper make, so the review cannot say how much the shocks absorb. Two owner posts ask about the rear shock on this model, one on the length of the rear shock and one on rear suspension, and the maker's record does not answer either question. A shock is a fact to check on the bike you buy.

Weight and load

Ridstar publishes no bike weight for the Q20 Pro and no maximum load. Its ridstar.net catalog carries a weight field of 39.9 kg (88.0 lb) for the product, which is not labeled as a bike weight. Our own listing gives a 330 lb load figure, which is ours; the maker prints none.

Ridstar's studio photograph, gallery image 8. It gives no bike weight.

The Q20 Pro's record prints no item weight, and this review compares its catalog field with no other model's figure. The model runs the Q20 Pro at 88.0 lb, the only weight figure the maker's record carries for this bike, and it stops the rider rows at 260 lb. If you weigh more than 260 lb with your cargo, the weight table stops below your figure, and Ridstar prints no maximum load to set against it.

A heavier bike costs range on every ride, and the weight table shows the cost is larger on a climb: your share and the bike's share move the same way.

Is the Q20 Pro UL certified?

Ridstar's ridstar.net record calls the Q20 Pro's batteries "UL-certified 52V 20Ah batteries, totaling 40Ah." Its ridstar.com page makes no UL claim, and neither store prints a certificate, a file number or the standard behind the claim. UL Solutions certifies e-bikes to UL 2849, which examines the drive train, battery and charger as one system.

For any e-bike, ask the seller for the certificate holder's name and the UL file number before paying, and check that both match the bike and the battery you are buying. A claim about the battery alone does not establish a certificate for the whole machine.

The Commission's fire warning concerns this model's batteries and wires, and it counts "11 reports of fire, including one burn injury" (as tabled above). A UL claim on the battery does not answer that count.

Has the Q20 Pro been recalled?

No. The CPSC's recall list carries no Ridstar recall, and both notices on the Q20 family are warnings and are not recalls. On October 12, 2026, the Commission's recall feed, 40 items, held no Ridstar, Xingqishi, HK Ridstar or YVY term.

If you own one, no recall also means no recall remedy: neither warning names a refund, a repair or a replacement. The Commission's instrument for this model is a warning.

Britain has its own record. The Office for Product Safety and Standards reported Ridstar's "Q20-Plus, Q20-Mini, E26 Pro and Chargers" as a serious fire risk on June 19, 2025, because "the charger has poor quality soldering, and the transformer does not meet the minimum requirements for creepage and clearance distances." The import "has been rejected at the border."

The report does not name the Q20 Pro, and whether its UK names match bikes sold in the US is not published.

Two lawsuits over Ridstar front wheels

Two product-liability suits allege that a Ridstar front wheel came off. Neither has been decided, neither names the Q20 Pro, and Ridstar is not a named defendant in either. Both are allegations in complaints, read from the federal dockets on October 12, 2026.

From the Cunanan docket and the L.E. docket on CourtListener.

The Cunanan complaint alleges that the front wheel of the Ridstar Q20 is "held on exclusively by the open-dropout fork frame, a shaft, shim, lock washer, tab washer, and a nut", and that the bike "does not include a 'Wheel quick release adjustment' component." Those are the complaint's words about the Q20, a different model from the Pro.

The L.E. complaint identifies its bike by a Walmart listing title and cites both CPSC warnings about the Q20 family, without calling the bike a Q20 Pro.

No e-bike class fits the Q20 Pro's figures

On Ridstar's own figures, a 2,000 W system and 34 mph sit outside the definitions the e-bike classes are built on, and Ridstar's pages assign the Q20 Pro no class. Its top speed differs by page, so the reading below runs on each figure Ridstar prints.

At the federal level, 15 U.S.C. § 2085(b) defines a low-speed electric bicycle as one 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."

Statute text read October 12, 2026 at govinfo and California's legislative site. Ridstar's figures from its pages and infographic.

In California the motor limb alone takes the Q20 Pro outside the electric bicycle definition, because § 312.5(a) tests a motor that "does not exceed 750 watts of power" and this one is rated at 2,000 W in total. Each of its two motors is 1000 W, so the bike is over the limit whichever way the motors are counted.

The code's other definition, for a motorized bicycle or moped under § 406(a), has "a motor that produces less than 4 gross brake horsepower" and is "capable of propelling the device at a maximum speed of not more than 30 miles per hour on level ground." A 2,000 W motor is about 2.7 horsepower, so the horsepower limb is met.

The speed limb is met only on ridstar.net's 28+++ mph and not on the 34 mph spec block or the 37 mph infographic. Which definition could apply therefore turns on the speed Ridstar's record gets right, and Ridstar has printed three. This review does not decide that question, and a moped is a different vehicle with its own rules.

Outside California, your state's own definition may use the same two numbers or different ones, and the census below lists each state's basis.

Our census of the state definitions, read September 24, 2026, covers 51 rows (50 states and the District of Columbia). Forty-four of them set a motor limb of 750 watts. Rhode Island sets 2 SAE horsepower, about 1,491 watts. Alaska and Kentucky define no electric bicycle.

Montana and New Jersey set no motor limb in the sections the census reads. The District's definition uses a 20 mph speed limit instead, and Oregon's current definition, ORS 801.258, sets classes at 20 and 28 mph with no motor watt limit. Our 50-state e-bike law atlas sets out each definition, and the California page covers the state most often named in the Q20 searches we harvested.

Where you can ride it

A path or trail that admits e-bikes by class admits this machine only if its own posted wording says so, and on Ridstar's figures no class covers the Q20 Pro. In California, if the bike is read as a motorized bicycle, § 21207.5(a) keeps it off "a bicycle path or trail, bikeway, bicycle lane", and off hiking or recreational trails, unless it is "within or adjacent to a roadway" or a local ordinance permits it.

Ridstar's lifestyle photograph, gallery image 5. It names no trail or ride, so it says nothing about where the bike may go.

Each rulebook reads its own posted wording first. The specification only matters once that wording names watts or speed.

National Forest rules define a motor vehicle as "any vehicle which is self-propelled, other than" a vehicle operated on rails or a wheelchair or mobility device (36 CFR 261.2), and a breach of a Part 261 rule carries "imprisonment of not more than six months or a fine in accordance with" the federal criminal code (36 CFR 261.1b). Our public-land guide covers each federal land agency.

Green and red flags

The green flags are checkable facts on the maker's page. The red flags each end in something you can do before you buy or ride.

Green flags

• The pack and motor ratings come from the maker. Ridstar's own pages print the battery configuration (two 52 V 20 Ah packs) and the motor rating per motor (1000 W), so the figures can be checked against the bike you are offered.
• The fit basics are published. Ridstar's pages print a rider-height window and a 20 × 4.0 tire.
• There is a published return window. Its store offers a 15-day money-back guarantee on the ridstar.com page, subject to its return terms.
• A positive owner account exists. One owner posted in October 2025 that "she still holds up well even after a year!" and cited more than 5,000 miles in the post's title. That is one person's account.

Red flags

• A federal warning covers this model. The Commission names this model in a fire warning and urges owners to remove and dispose of the battery. Read the instruction before you buy, and follow it for any unit you own.
• No recall covers this model. The manufacturer "has refused to agree to an acceptable recall", according to the Commission. Ask any seller in writing whether a recall is open, and do not rely on a warranty from a store that does not sell to you.
• The top speed differs across the maker's pages. Ridstar prints three top speeds (34, 37 and 28+++ mph), two climbing angles and four warranty statements. Read the specification, then ask for the measured figures in writing before any purchase.
• The payload and weight are unpublished. No bike weight and no maximum load are published for the Q20 Pro. Ask the seller for both in writing before you buy.
• Battery fires are in the owner reports. Owners describe a battery fire on this model. One post from October 12, 2024 reads: "Front battery smoked and flames so fast all I could do was get off." Check the battery on any unit before you ride it.
• Wheel damage is in the owner reports. Owners describe a curb strike that damaged a front wheel and rims. Inspect the front axle, spokes and rims before each ride.
• Our listing and the maker's page disagree on the battery. Our listing prints one 20 Ah pack and 1,040 Wh, and the maker prints two packs. Email us and ask which pack the bike you are offered carries; we will answer in writing.

Buy it if, buy something else if

Buy the Q20 Pro if you want two motors on 20 × 4.0 tires, you ride where a machine outside the e-bike classes is allowed, and you have read the Commission's warning and still choose this bike. Ours is open for orders at $1,574.35, against the $1,999 that Ridstar's own store listed for its US version on October 14, 2026.

Buy something else if you want a fat-tire bike within the 750 W limb that 44 of the 51 state rows in our census set, or a bike whose class is stated on its page. Our fat-tire buying guide lists the bikes we sell for that use.

One bike we sell puts the Q20 Pro's 20 × 4.0 tire size inside a class: the VTUVIA SF20H, $1,299 on October 14, 2026. VTUVIA rates it at 750 W and delivers it as a Class 2 bike set to 20 mph, with a 70 mile maximum range and a 330 lb payload in its own figures.

VTUVIA's page says the 20 mph setting can be adjusted, so read your state's definition before you change it.

Buy something else if you ride a path or trail that admits e-bikes by class. The class wording at the trailhead decides that, and a 2,000 W, 34 mph machine is outside every class on Ridstar's figures.

Buy something else if you need the warranty holder to be the store you bought from. Ridstar's own pages say its warranty applies only to buyers from its own site, so read our warranty answer before you decide.

Before you buy: the checklist

Six checks cover the Q20 Pro, whether you own one or are weighing one: the receipt, the Commission's instruction, the seller's written answers, your state's definition, the front wheel and the saddle. The first two come before anything else you do with the bike.

1. Read your receipt. A model number of Q20 or Q20 Pro falls under the March 19, 2026 warning. A model number of Q20 or Q20 Lite falls under the June 25, 2026 warning as well.
2. If you own one, stop using it. Remove the battery, take it to a hazardous waste collection point, and keep the receipt. Do not sell or give the bike or the battery away.
3. Ask any seller in writing for the model number, the battery's certificate holder and UL file number, the warranty holder and the warranty terms, and the measured top speed and motor watts, if they have been measured.
4. Check your state's definition and the posted class wording on any path or trail you plan to use, before the first ride.
5. Inspect the front wheel at each ride: the axle nut or quick release, the spokes, and the rim walls. Owner posts describe cracked rims after a curb strike, and one describes a shop saying the headset bearings need replacing.
6. Set the saddle with the heel check in the setup subsection, and use the saddle table for your inseam band.

Buying it from us

Our Q20 Pro is open for orders at $1,574.35 on October 14, 2026, which is $424.65 under the $1,999 that Ridstar's own store listed for its US version that day, with every variant there sold out. Our listing does not track inventory, so it stays available to order.

At $1,574.35, the bike costs $315 a year over five years, before charging, insurance or repair. The Commission's instruction governs any unit you own, including one bought here.

Ridstar's warranty applies only to buyers from its own site, according to its pages, and its record gives four different warranty statements (see the specification).

For a bike that will not power on, will not charge, shows an error code or has a faulty component, our refund policy says it is "covered under manufacturer warranty", and we coordinate the repair or replacement remotely.

Ridstar's pages say its warranty is available only to buyers from its own store. For a bike bought here, those two statements do not agree, and this review does not settle the disagreement. Ask us in writing which of them applies to the unit you are offered before you buy.

Our refund policy, read October 14, 2026, takes change-of-mind returns only for unopened bikes in factory-sealed packaging, requested within 72 hours of delivery, with a 15% restocking fee and return shipping at the buyer's cost. Damage, defect and incorrect-item claims must be reported within 48 hours of delivery.

Frequently asked questions

Is the Ridstar Q20 Pro safe?

Not while the Commission's warning stands. The March 19, 2026 warning names the Q20 Pro for battery and wiring fires, reports 11 fires, and urges owners to remove the battery and dispose of it. Ridstar has not agreed to a recall, according to the Commission.

Was the Ridstar Q20 Pro recalled?

No. The CPSC lists two warnings on the Q20 family, and neither is a recall. No refund, repair or replacement is offered under either.

How fast does the Ridstar Q20 Pro go?

Ridstar prints three figures: 34 mph on its product page, 37 mph on an infographic, and 28+++ mph on ridstar.net. The review does not choose one, and the speed you can reach depends on the rider and the bike, which the record does not measure.

How far can the Ridstar Q20 Pro go on one charge?

The model computes 99 miles at 15 mph on the throttle, 76 at 20 mph and 134 at 15 mph with easy pedaling, on flat pavement with a 180 lb rider on an 88 lb bike. The planning figure keeps a quarter of the pack: 74 miles at 15 mph. Your own figure moves with your speed, climbing, weight and the air temperature, and the range section lists the conditions for each.

How tall do you need to be for the Ridstar Q20 Pro?

Ridstar's spec block says 5'4" to 6'2", and its product card says 5'4" to 6'4". If you are 5'10" with a median inseam of 33.8 inches, the formula sets your saddle top 36.8 inches above the pedal axle, and the saddle table gives the figures for your height.

How much does the Ridstar Q20 Pro weigh?

Ridstar publishes no bike weight for the Q20 Pro. Its ridstar.net catalog carries a field of 39.9 kg (88.0 lb), which is not labeled as the bike's weight. Ask the seller for the weight in writing.

What is the Ridstar Q20 Pro's weight limit?

Ridstar publishes no maximum load for the Q20 Pro. Our listing gives 330 lb, and that figure is ours; the maker prints none. The range model stops its rider rows at 260 lb.

Is the Ridstar Q20 Pro street legal, and what class is it?

On Ridstar's figures, it falls outside the federal low-speed electric bicycle definition, which needs a motor of less than 750 watts and a top speed below 20 mph. In California it falls outside the electric bicycle definition on its motor alone. Ridstar's pages assign it no class, and the class section explains which definitions could apply.

Is the Ridstar Q20 Pro legal in California?

It is outside the California electric bicycle definition on the motor, because the code's limit is 750 watts and the bike is rated at 2,000 W in total. Whether it is a moped depends on the speed Ridstar gets right, which the review does not decide. Check the California page before any ride.

Does the Ridstar Q20 Pro have a throttle?

Yes. Ridstar's infographic lists three modes: bike mode, pedal-assist and throttle mode, and its page gives the throttle range as 75 miles. The range model computes the throttle ride at each speed.

Does the Ridstar Q20 Pro have hydraulic brakes?

Ridstar's infographic says "Dual Hydraulic Disc Brakes". The record does not name the brake maker, the pad or the rotor size, so the review cannot confirm them. Ask the seller for the specification.

How long does the Ridstar Q20 Pro take to charge?

Ridstar prints 4 to 6 hours. Its page prints no charger rating, so the review does not compute a charge cost.

Is the Ridstar Q20 Pro worth it?

It depends on how you weigh the warning against the price. Ours is $1,574.35, $424.65 under the $1,999 that Ridstar's own store listed for its US version on October 14, 2026, for two motors and 20 × 4.0 tires. Against that, the Commission's March 19, 2026 warning names this model for battery and wiring fires, no recall offers a remedy, and on Ridstar's figures the bike sits outside every e-bike class.

Limitations of this review

Each item below is a limit on what this page can tell you about the Q20 Pro, with what it means for your own decision on the bike.

1. Ridstar's figures conflict, and every conflict is on this page. Top speed (34, 37 and 28+++ mph), torque and climbing (90 N·m per motor, and 40° and 45° slopes), range (75 miles on the throttle and 180 in assist mode), rider height (5'4" to 6'2" and 5'4" to 6'4"), warranty (two years in two places, one year on the components, and one year on the motor, battery and charger), and the battery (two packs, or one on our listing) are each printed beside the other.
2. Ridstar publishes no bike weight, no maximum load and no geometry for this model. The cockpit lean, the standover and the hand load are not computed. The record's own catalog weight of 88.0 lb is a catalog field, and the model uses it as the only weight figure the record carries.
3. The fit tables use the US Army's ANSUR II survey, 4,082 men and 1,986 women in the 2012 survey, a population different from the general public. Your own inseam outranks any row.
4. The saddle formulas are averages. Published recommendations run from 106% to 110.4% of inseam, and the heel check in the setup subsection is the test on your own leg.
5. The motor in the range model is a comparable whose curve is not the Q20 Pro's own. Bafang's published curve is rebuilt at 52 V and 2,000 W. Its efficiency is the source of most of the model's uncertainty, and the model's figure moves with it. We print that movement in the range section.
6. The wheel size is borrowed. Ridstar prints no wheel diameter for the Q20 Pro, so the model uses 22.8 inches from Samebike's printed figure for the same 20 × 4.0 tire (read October 2, 2026). It sets the torque a climb needs and does not change the flat-road figures.
7. No ride of the Q20 Pro to an empty pack is used. The model's miles are checked against published physics and the maker's own figures, with no measured ride behind them, so every range figure here is computed.
8. The Q20 Pro's tires were not measured. The bracket covers the ten 26 × 4.00 fat tires the drum recorded, from the lowest-rolling to the highest-rolling.
9. The cold table uses LG HG2 cell data, and Ridstar names no cell for the Q20 Pro. The brackets widen below freezing, because published cell tests disagree there.
10. The speed behind the maker's range is not printed. Ridstar's figures in the range section show the ride each claim needs, and the maker prints neither figure's speed or effort.
11. The Commission's second warning does not name the Q20 Pro, and the Commission does not say whether the Pro has the front-wheel fault. This review does not say it does.
12. No Q20 Pro manual was located. Ridstar's manual pages hold certificates and return-policy text, and the two scanned manuals on its file server name no model. Anything only a Pro manual would say, such as a tire pressure or a battery disposal step, is unknown here.
13. The UL claim has no certificate or file number on either store, so the review cannot confirm it.
14. Owner accounts are individual reports. The Reddit and maker-page quotations are each one person's words, quoted with a link and a date, and none is counted into any statistic.
15. The two lawsuits are allegations, stated as the complaints put them, with the dockets as of October 12, 2026. Neither has been decided, and neither names the Q20 Pro.
16. The state census is a reading of statutes as published, on September 24, 2026. A law changed after that date, or a rule an agency applies without a statute, is outside it. Our atlas is the place for each state's current definition.
17. Our own listing differs from the maker in the battery and the payload. The review follows the maker, and the difference is disclosed here and in the battery section.

The bottom line

The Q20 Pro puts two motors on 20 × 4.0 tires for $1,574.35, and the Commission's March 19, 2026 warning names it for battery and wiring fires, urges owners to remove the battery and dispose of it, and no recall offers a remedy.

On Ridstar's own figures the bike is a 2,000 W, two-battery machine that is outside the California e-bike definition and over the 750 W limb in 44 of the 51 state rows we read. Buy it if you ride where such a machine is allowed and want it with the warning in view.

Ours is $424.65 under the $1,999 that Ridstar's own store listed for its US version on October 14, 2026, when every variant there showed sold out. If you own one, follow the Commission's instructions first.

If you want the same 20 × 4.0 tire size inside a class, the VTUVIA SF20H is $1,299 with free shipping within the contiguous United States, and our fat-tire guide lists the bikes we sell for the same kind of ride.

Image credit: every image below the cover is Ridstar's own photograph, the studio views, the rider on rock and the two wheel close-ups included; the close-ups are crops, and none is retouched.

Cover: Ridstar's own side-view studio photograph of the Q20 Pro, scaled uniformly with no pixel of the bike changed; the studio around it was generated on Playcut (playcut.ai) with Nano Banana Pro, and the type and its shading are laid on top.

Source register

Each source behind this review is listed below with the tier we grade it at, the claim it supports and the date we read it, so you can open any of them and check the figure yourself.

Expiry conditions

Any of these would date the page: a recall, a new warning or a change to either warning from the CPSC; a new figure, a changed listing or a manual on either Ridstar store; or a ruling or a new filing in either lawsuit.

So would a change to our listing's price, stock or battery figure, or to our shipping or refund policy; a change to 15 U.S.C. § 2085 or to California Vehicle Code §§ 312.5, 24016, 406 or 21207.5; or a change to any state definition in our census. Verified October 12, 2026.

References

Each document cited on this page is listed with its publisher, its title, the part relied on and the date it was retrieved, so you can check any figure at its source.

1. U.S. Consumer Product Safety Commission, CPSC Warns Consumers to Immediately Stop Using Ridstar E-Bikes Due to Fire Hazard; Risk of Serious Injury or Death. CPSC warning 26-337, March 19, 2026: names the Ridstar Q20 and Q20 Pro; fire hazard; remove and dispose of the battery; 11 reports of fire. Retrieved Oct 12, 2026. https://www.cpsc.gov/Warnings/2026/CPSC-Warns-Consumers-to-Immediately-Stop-Using-Ridstar-E-Bikes-Due-to-Fire-Hazard-Risk-of-Serious-Injury-or-Death
2. U.S. Consumer Product Safety Commission, CPSC Warns Consumers to Stop Using Ridstar E-Bikes Immediately Due to Crash Hazard; Risk of Serious Injury or Death. CPSC warning 26-584, June 25, 2026: names the Ridstar Q20 and Q20 Lite (not the Q20 Pro); front wheel detachment; 32 reports. Retrieved Oct 12, 2026. https://www.cpsc.gov/Warnings/2026/CPSC-Warns-Consumers-to-Stop-Using-Ridstar-E-Bikes-Immediately-Due-to-Crash-Hazard-Risk-of-Serious-Injury-or-Death
3. U.S. Consumer Product Safety Commission, Product safety warning listing (CSV). CPSC product safety warning listing (CSV): both Ridstar warnings listed, read October 12, 2026. Retrieved Oct 12, 2026. https://www.cpsc.gov/s3fs-public/recall-data/product_safety_warning_listing.csv
4. U.S. Consumer Product Safety Commission, Recalls & Product Safety Warnings. CPSC recalls page: no Ridstar recall; the recall list and feed read October 12, 2026, with a control. Retrieved Oct 12, 2026. https://www.cpsc.gov/Recalls
5. Office for Product Safety and Standards (UK), Product Safety Report: Ridstar E-Bikes and Chargers (2506-0011). UK OPSS product safety report 2506-0011, June 19, 2025: Q20-Plus, Q20-Mini, E26 Pro and chargers; not the Q20 Pro. Retrieved Oct 12, 2026. https://www.gov.uk/product-safety-alerts-reports-recalls/product-safety-report-ridstar-e-bikes-and-chargers-2506-0011
6. U.S. District Court for the District of Oregon (docket via CourtListener RECAP), Cunanan v. Amazon.com Services LLC, No. 3:26-cv-00692. Cunanan v. Amazon.com Services LLC, No. 3:26-cv-00692 (D. Or.): allegations about a Ridstar Q20; docket status. Retrieved Oct 12, 2026. https://www.courtlistener.com/docket/73159439/cunanan-v-amazoncom-services-llc/
7. U.S. District Court for the Southern District of Florida (docket via CourtListener RECAP), L.E., a minor, v. Walmart Inc., No. 9:26-cv-81045. L.E. v. Walmart Inc., No. 9:26-cv-81045 (S.D. Fla.): allegations about a Ridstar bike sold on Walmart.com; docket status. Retrieved Oct 12, 2026. https://www.courtlistener.com/docket/74691512/le-v-walmart-inc/
8. US Government Publishing Office, 15 U.S.C. § 2085 — Low-speed electric bicycles. 15 U.S.C. § 2085(b): the federal low-speed electric bicycle definition (under 750 W; under 20 mph). Retrieved Oct 12, 2026. https://www.govinfo.gov/content/pkg/USCODE-2024-title15/html/USCODE-2024-title15-chap47-sec2085.htm
9. California Legislative Information, California Vehicle Code § 312.5. Cal. Veh. Code § 312.5(a): the California electric bicycle definition ('does not exceed 750 watts of power'); class 2 limit of 20 mph. Retrieved Oct 12, 2026. https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=VEH&sectionNum=312.5.
10. California Legislative Information, California Vehicle Code § 406. Cal. Veh. Code § 406(a): motorized bicycle or moped (under 4 gross brake horsepower; not more than 30 mph on level ground). Retrieved Oct 12, 2026. https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=VEH&sectionNum=406.
11. California Legislative Information, California Vehicle Code § 21207.5. Cal. Veh. Code § 21207.5(a): motorized bicycles on bicycle paths and trails, and the exception for roadways. Retrieved Oct 12, 2026. https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=VEH&sectionNum=21207.5.
12. Forest Service, USDA (eCFR), 36 CFR § 261.13 — Motor vehicle use. 36 CFR 261.13: the National Forest motor vehicle use map rule. Retrieved Sep 26, 2026. https://www.ecfr.gov/current/title-36/chapter-II/subchapter-B/part-261/subpart-A/section-261.13
13. U.S. Department of Agriculture, Forest Service (Office of the Federal Register, eCFR), 36 CFR 261.2 Definitions. 36 CFR 261.2: the definition of motor vehicle (any self-propelled vehicle). Retrieved Sep 26, 2026. https://www.ecfr.gov/current/title-36/chapter-II/part-261/subpart-A/section-261.2
14. U.S. Department of Agriculture, Forest Service (Office of the Federal Register, eCFR), 36 CFR 261.1b Penalty. 36 CFR 261.1b: the penalty for a breach of Part 261. Retrieved Sep 26, 2026. https://www.ecfr.gov/current/title-36/chapter-II/part-261/subpart-A/section-261.1b
15. U.S. Army Natick Soldier Research, Development and Engineering Center, 2012 Anthropometric Survey of U.S. Army Personnel (ANSUR II), public data release 2017. ANSUR II, public release: the rider bodies (6,068) the fit model's saddle table is built on. Retrieved Sep 25, 2026. https://www.army.mil/article/188601/for_good_measure_natick_releases_raw_data_from_army_wide_anthropometric_survey
16. NOAA, NASA, US Air Force, U.S. Standard Atmosphere, 1976 (NOAA-S/T 76-1562; NASA TM-X-74335). U.S. Standard Atmosphere 1976: the air density used by the range model. Retrieved Sep 23, 2026. https://ntrs.nasa.gov/api/citations/19770009539/downloads/19770009539.pdf
17. BAFANG, BAFANG Workbook OEM 2021. Bafang OEM workbook 2021: the comparable motor curve (rated voltage, no-load speed, efficiency floor, maximum torque). Retrieved Sep 23, 2026. https://www.bafang-e.com/Uploaded/Labels/BAFANG%20Workbook%20OEM%202021.pdf
18. Bicycle Rolling Resistance (Jarno Bierman), Fat Bike Tires Test Results. Bicycle Rolling Resistance: ten fat-tire rolling-resistance tests on a drum (median and lowest), and a knobby casing (high bracket). Retrieved Sep 25, 2026. https://www.bicyclerollingresistance.com/fat-bike-reviews
19. Journal of Applied Biomechanics (Human Kinetics), Martin JC, Milliken DL, Cobb JE, McFadden KL, Coggan AR. Validation of a Mathematical Model for Road Cycling Power. Martin et al. (1998): the cycling-power model, its Appendix I values, and the chain efficiency. Retrieved Sep 23, 2026. https://collections.lib.utah.edu/dl_files/b4/8e/b48ef26086091662c561e673d7bd990d77868437.pdf
20. Journal of Sports Sciences (Taylor & Francis), Tengattini S, Bigazzi AY. Physical characteristics and resistance parameters of typical urban cyclists. Tengattini & Bigazzi (2018): frontal area and drag for upright cruisers and mountain bicycles. Retrieved Sep 23, 2026. https://civil-reactlab.sites.olt.ubc.ca/files/2022/11/Tengattini_2018_Physical-characteristics-and-resistance-parameters-of-typical-urban-cyclists.pdf
21. World Electric Vehicle Journal (MDPI), Arango I, Lopez C, Ceren A. Improving the Autonomy of a Mid-Drive Motor Electric Bicycle Based on System Efficiency Maps and Its Performance. Arango, Lopez & Ceren (2021): battery efficiency as a function of current. Retrieved Sep 23, 2026. https://mdpi-res.com/d_attachment/wevj/wevj-12-00059/article_deploy/wevj-12-00059.pdf
22. IEEE / EPE'19 ECCE Europe (Karlsruhe Institute of Technology authors), Schmitt M, Decker S, Doppelbauer M. Measuring and Characterization of a Pedal Electric Cycle (Pedelec) on a Full System Test-Bench. Schmitt, Decker & Doppelbauer (2019): a measured pedelec used 75% of its nominal pack. Retrieved Sep 23, 2026. https://publikationen.bibliothek.kit.edu/1000100371/50695920
23. McMaster University (Kollmeyer et al.), Mendeley Data, LG 18650HG2 Li-ion Battery Data and Example Deep Neural Network xEV SOC Estimator Script. LG 18650HG2 cell data (McMaster, Kollmeyer): cell energy relative to 25 °C at low temperature. Retrieved Sep 23, 2026. https://doi.org/10.17632/b5mj79w5w9.2
24. SAMEBIKE US, M20-III Off Road Peak 3000W Fat Tire Electric Bike — product page. Samebike M20-III product page: the 22.8-inch figure for the same 20 × 4.0 tire (the wheel comparable). Retrieved Oct 2, 2026. https://us.samebike.com/products/m20-iii-off-road-peak-3000w-fat-tire-electric-bike
25. Journal of Exercise Physiology Online (American Society of Exercise Physiologists), Peveler et al., Comparing methods for setting saddle height in trained cyclists, JEPonline 8(1):51-55. Peveler et al. (2005): saddle-height methods compared, the 109% formula and the heel method. Retrieved Sep 25, 2026. https://www.asep.org/asep/asep/JEPonlineFEBRUARY2005_PevelerSaddle.doc
26. Journal of Strength and Conditioning Research (NSCA), Ferrer-Roca V, Roig A, Galilea P, Garcia-Lopez J. Influence of saddle height on lower limb kinematics in well-trained cyclists: static vs. dynamic evaluation in bike fitting. J Strength Cond Res 26(11):3025-9; doi 10.1519/JSC.0b013e318245c09d. Ferrer-Roca et al. (2012): the knee-angle band used for the 25 to 35 degree target. Retrieved Sep 25, 2026. https://pubmed.ncbi.nlm.nih.gov/22190163/
27. Journal of Strength and Conditioning Research (NSCA), Peveler, Pounders & Bishop, Effects of saddle height on anaerobic power production in cycling, JSCR 21(4):1023-7. Peveler, Pounders & Bishop: saddle height and knee range in trained cyclists. Retrieved Sep 25, 2026. https://pubmed.ncbi.nlm.nih.gov/18076230/
28. University of Colorado Boulder (MS thesis), Carahalios A. An Analysis of the Bicycle-Rider Interface Forces in Stationary Road Cycling (MS thesis, Department of Integrative Physiology, University of Colorado). Carahalios (2015): hand load on the stem, about 15% of body weight, ten road racers on the hoods. Retrieved Sep 25, 2026. https://scholar.colorado.edu/downloads/70795789x
29. UL Solutions, E-Bikes Certification: Evaluating and Testing to UL 2849. UL Solutions: e-bike certification to UL 2849, which covers the drive train, battery and charger as one system. Retrieved Sep 26, 2026. https://www.ul.com/services/e-bikes-certificationevaluating-and-testing-ul-2849
30. Redtail eBikes, Refund policy. Redtail eBikes refund policy: unopened change-of-mind returns within 72 hours, 15% restocking fee, 48-hour defect claims, and the manufacturer-warranty line. Retrieved Oct 12, 2026. https://redtailebikes.com/policies/refund-policy
31. YVY / HK Ridstar Trade Limited (yvyebike.com), Company Address. YVY company address: the business is HK Ridstar Trade Limited. Retrieved Oct 12, 2026. https://yvyebike.com/pages/company-address
32. YVY / HK Ridstar Trade Limited (yvyebike.com), Ebike Warranty. YVY ebike warranty page: its warranted products include 'YVY Q20Pro 2000W Fat Tire Electric Bicycle'. Retrieved Oct 12, 2026. https://yvyebike.com/pages/ebike-warranty
33. Ridstar (ridstar.net), Ridstar Official Statement. Ridstar Official Statement (ridstar.net): after-sales service limited to customers who buy from its own store. Retrieved Oct 12, 2026. https://ridstar.net/pages/ridstar-official-statement
34. Ridstar (ridstar.com), Ridstar Q20 1500W 48V 20AH Fat Tire Ebike — product record (.js). Ridstar.com Q20 1500W product record: item weight 66 pounds (a different bike; comparison only). Retrieved Oct 12, 2026. https://ridstar.com/products/ridstar-q20-1500w-fat-tire-ebike.js
35. Ridstar (ridstar.net), All products — ridstar.net catalog. Ridstar.net catalog, read October 12, 2026: the Q20 Pro absent from its titles; a battery variant labelled 'US / Q20 Pro' available. Retrieved Oct 12, 2026. https://ridstar.net/collections/all
36. Ridstar (ridstar.com), Ridstar Q20Pro 2000W Fat Tire Electric Bicycle — product page. Spec block (Max Speed 34 MPH; Max Range 75/180 miles; Recommended Height 5'4" -6'2"; 52V 40AH (20AH2); 2000W (1000W2); torque 90NM x 2; 45° and 40° slope lines); 'Hassle-Free 2-Years Warranty' heading; sold-out status; 15-day money-back guarantee; warranty-policy paragraph; product card '5'4" -6'4"'. Retrieved Oct 12, 2026. https://ridstar.com/products/ridstar-q20pro-2000w-fat-tire-electric-bicycle
37. Ridstar (ridstar.com), Ridstar Q20Pro 2000W Fat Tire Electric Bicycle — product record (.js). Description table: Warranty Type 'One-year warranty for the e-bike components and lifetime tech support'; Warranty Description; Charging Time; the five market variants, all unavailable; variant weight 0. Retrieved Oct 12, 2026. https://ridstar.com/products/ridstar-q20pro-2000w-fat-tire-electric-bicycle.js
38. Ridstar (ridstar.net), archived, Ridstar Q20Pro 2000W Fat Tire Ebike — ridstar.net product record (Wayback capture of August 30, 2026; deposit of August 26, 2026). Description: 'a top speed of 28+++mph'; 'up to 180 miles in pedal-assist mode'; 'UL-certified 52V 20Ah batteries, totaling 40Ah'; '20" x 4.0" fat tires'; 'Shimano 7-speed gear system'; '1-year warranty on the motor, battery, and charger'; US variant weight 39916 g. Retrieved Oct 12, 2026. http://web.archive.org/web/20260830064726/https://ridstar.net/products/ridstar%c2%ae-q20pro-2000w-fat-tire-ebike
39. Ridstar (ridstar.com gallery), Ridstar Q20Pro gallery image 1 (infographic): 'Front & Rear Shock Absorption', 'Super Bright Headlight', 'Rearview Mirror', 'Dual Hydraulic Disc Brakes'. Image text, read by eye 2026-10-13. Retrieved Oct 13, 2026. https://cdn.shopify.com/s/files/1/0658/3225/5545/files/idstar-Q20-pro-3.webp?v=1755067878
40. Ridstar (ridstar.com gallery), Ridstar Q20Pro gallery image 2 (infographic): 'POWERFUL BRUSHLESS MOTOR 2000W', '0-3 Seconds up to 34mph', '37MPH Top Speed', '90NM×2 Max Torque', '45° Climbing Slope'. Image text, read by eye 2026-10-13. Retrieved Oct 13, 2026. https://cdn.shopify.com/s/files/1/0658/3225/5545/files/idstar-Q20-pro-2.webp?v=1755067878
41. Ridstar (ridstar.com gallery), Ridstar Q20Pro gallery image 4 (infographic): 'ASSISTED RIDING (180 MILE)', 'THROTTLE MODE (MAX 75 MILES)', bike mode, pedal-assist and throttle modes. Image text, read by eye 2026-10-13. Retrieved Oct 13, 2026. https://cdn.shopify.com/s/files/1/0658/3225/5545/files/idstar-Q20-pro-5.webp?v=1755067878
42. Redtail eBikes (our listing), Ridstar Q20 Pro Dual-Motor Fat Tire Electric Bike, 52V 20Ah — our product page. Title and body: '52V 20Ah (1,040Wh)' single pack; SEO description; price 1574.35; tracksInventory false, policy DENY; maximum load 330 lb (ours only); rider height 'Not published by Ridstar for this model' (registered as false). Retrieved Oct 12, 2026. https://redtailebikes.com/products/ridstar-q20pro-2000w-fat-tire-ebike
43. Reddit, r/ebikes (an owner), I think I just ruined my Ridstar Q20 Pro. Post of 2025-08-25: 'hit a sneaky curb. Now my front wheel makes a scraping noise, whistles, and the axle wobbles a bit.'. Retrieved Oct 12, 2026. https://www.reddit.com/r/ebikes/comments/1n0192r/i_think_i_just_ruined_my_ridstar_q20_pro/
44. Reddit, r/ebikes (an owner), Ridstar Q20 Pro both rims is cracked. Post of 2025-09-03: 'Hello. Anyone with this problem? The both rims its cracked.'. Retrieved Oct 12, 2026. https://www.reddit.com/r/ebikes/comments/1n7ao64/ridstar_q20_pro_both_rims_is_cracked/
45. Reddit, r/ebikes (an owner), Q20 Pro explodes. Post of 2024-10-12: 'Front battery smoked and flames so fast all I could do was get off before I lost a leg'. Retrieved Oct 12, 2026. https://www.reddit.com/r/ebikes/comments/1g2bcpz/q20_pro_explodes/
46. Reddit, r/ebikes (an owner), Only a year of owning this bike and over 5000 miles!. Post of 2025-10-08: 'she still holds up well even after a year! Safe to say best purchase yet!'. Retrieved Oct 12, 2026. https://www.reddit.com/r/ebikes/comments/1o1pffy/only_a_year_of_owning_this_bike_and_over_5000/
47. Reddit, r/ebikes (an owner), Brakes for Ridstar Q20 Pro. Post of 2026-08-02: 'Looking for suggestions of cheap brake replacements for my Q20 pro!'. Retrieved Oct 12, 2026. https://www.reddit.com/r/ebikes/comments/1vdw5vc/brakes_for_ridstar_q20_pro/
48. Reddit, r/ebikes (an owner), Rear suspension for Ridstar Q20 Pro?. Post title of 2025-07-28 (a question; no answer read). Retrieved Oct 12, 2026. https://www.reddit.com/r/ebikes/comments/1mbutyb/rear_suspension_for_ridstar_q20_pro/
49. Reddit, r/ebikes (an owner), Ridstar Q20 Pro rear shock length. Post title of 2025-07-10 (a question; no answer read). Retrieved Oct 12, 2026. https://www.reddit.com/r/ebikes/comments/1lw43g7/ridstar_q20_pro_rear_shock_length/
50. State of Oregon (Oregon Legislature), Oregon Revised Statutes 801.258 (electric bicycle definition as amended by HB 4103, 2024 c.12 § 1). The 1,000-watt motor limb deleted in 2024; no motor limb in the section read. Retrieved Sep 24, 2026. https://www.oregonlegislature.gov/bills_laws/ors/ors801.html
51. State of Rhode Island (General Assembly), Rhode Island General Laws § 31-1-3 (motorized bicycle and electric bicycle definitions). 'rated not more than two (2) (S.A.E.) horsepower' (about 1,491 W). Retrieved Sep 24, 2026. https://webserver.rilegislature.gov/Statutes/TITLE31/31-1/31-1-3.HTM
52. District of Columbia (DC Council), DC Code § 50-2201.02 (motorized bicycle definition). 'A motor incapable of propelling the device at a speed of more than 20 miles per hour'; no motor-watt limb. Retrieved Sep 24, 2026. https://code.dccouncil.gov/us/dc/council/code/sections/50-2201.02
53. VTUVIA (maker), VTUVIA SF20H Utility Ebike — maker product page. VTUVIA's figures for the SF20H: a 750 W rear hub motor (1,200 W peak), Class 2 set to 20 mph and adjustable, a 48 V 14 Ah (672 Wh) pack certified to UL 2271, a 70 mile maximum range, a 330 lb payload, 20 x 4 fat tires. Retrieved Oct 14, 2026. https://vtuviaebike.com/products/sf20h-fat-tire-folding-electric-bike-ul-certified-ebike
54. Playcut, Playcut. Tool credit: Playcut, where the studio around Ridstar's side-view studio photograph of the Q20 Pro on the cover was generated with Nano Banana Pro (the studio of another of our reviews, reused), credited with a backlink; not a source of any fact. Retrieved Oct 13, 2026. https://playcut.ai
55. Redtail eBikes, Shipping policy. Our shipping terms: free shipping on every e-bike within the contiguous United States; P.O. boxes and remote areas may cost extra or be excluded. Retrieved Oct 14, 2026. https://redtailebikes.com/policies/shipping-policy
56. Ridstar (ridstar.com), Ridstar Q20Pro 2000W Fat Tire Electric Bicycle — product record, US storefront. Ridstar's own store listed the Q20 Pro's US version at $1,999 on October 14, 2026, with every variant sold out. Retrieved Oct 14, 2026. https://ridstar.com/products/ridstar-q20pro-2000w-fat-tire-electric-bicycle
57. Redtail eBikes, Refund policy. Our refund terms: change-of-mind returns only for unopened bikes in factory-sealed packaging, requested within 72 hours of delivery, with a 15% restocking fee and return shipping at the buyer's cost; damage, defect or an incorrect item reported within 48 hours of delivery; a bike that will not power on, will not charge, shows an error code or has a faulty component is covered under manufacturer warranty, and we coordinate the repair or replacement remotely. Retrieved Oct 14, 2026. https://redtailebikes.com/policies/refund-policy
58. Redtail eBikes (our state census), Our census of state e-bike definitions, 51 rows (50 states and DC), read September 24, 2026. Motor limb per row: 44 rows at 750 W; Rhode Island 2 SAE hp; Alaska and Kentucky no e-bike definition; District, Montana, New Jersey and Oregon set no motor limb. Retrieved Sep 24, 2026. https://redtailebikes.com/blogs/journal/electric-bike-laws