VTUVIA SX20 Review 2026: Folding Step-Thru, 672 Wh

$1,299 · a rear hub motor rated at 750 W, 1,200 W peak · a 48 V 14 Ah LG pack of 672 Wh · Class 2 as delivered, 20 mph · a folding step-through frame, 13.8 or 15.4 in over the step · 20 × 4.0 tires and hydraulic brakes · 70 lb; 330 lb total capacity · verified September 29, 2026

Quick Answer — The SX20 Antelope is VTUVIA's folding step-through fat tire bike: a 750 W rear hub motor, a 672 Wh LG pack, 20 × 4.0 tires and hydraulic brakes, for $1,299. On level ground at a steady 15 mph on the throttle, a 180 lb rider gets about 37 miles from a full charge.

Pedal gently and the same charge reaches about 56 miles; hold 20 mph on the throttle and it drops to about 26. VTUVIA's product page lists 70 miles on pedal assist and 40 on the throttle alone, and the range tables turn each into a ride you can plan.

The seat post suits most riders from 5'0" to 5'9", the frame steps through low, and the whole bike folds to fit a trunk or an RV bay. The fit section prints your row, and the class section reads VTUVIA's 750 W and 20 mph against the federal and California definitions.

What this review covers

The specification · What it is · Folding · Fit · The motor · The battery · Range · Brakes, display and lights · Fork, tires, gears and water · Weight, load and the rack · The Mercer fit test · Recalls · Class · Green and red flags · The verdict · Checklist · Buying it from us · FAQ · Limitations · The bottom line · References

How we verified this VTUVIA SX20 review

Every figure below was read on September 28 and 29, 2026 from VTUVIA's SX20 product page, its product record, VTUVIA's SX20 specifications page and SX20 size chart, our own listing, and the statutes quoted in the class section. Range and fit are computed, and each section names the inputs it rests on.

This review is specification-verified: each number traces to VTUVIA, to a statute, or to arithmetic shown on the page, and the range model reproduces two published benchmarks before it computes anything. We sell the SX20, so read the red flags with the same care as the green ones.

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

The SX20 on paper: VTUVIA's specification

These rows repeat VTUVIA's own words and figures as they read on September 28, 2026: the specification table, geometry table, feature blocks and FAQ of the SX20 page, the specifications page for its 52 miles, 5-to-6-hour charge and 9.35 lb pack, and the size chart for its second set of lengths. 48 volts times 14 amp-hours is the 672 Wh.

VTUVIA prints two sets of SX20 lengths, and they disagree by a few inches. The product page's geometry table and the separate size chart share the 22.5-inch top tube, the 5.5-inch head tube and the 24-inch bar, and part ways on the overall length, the wheelbase and the standover. Wherever the two differ, this page prints both, and the fit section shows which set VTUVIA's own photograph matches.

A folding step-through fat tire bike, the Antelope

The SX20 is the folder VTUVIA builds for riders who want a low frame and wide tires in one package. Its page calls it a "Compact Folding Ebike for Smaller Riders", the frame carries the word ANTELOPE, and VTUVIA's store record for it was created on November 22, 2022.

Two riders straddle their SX20s at a stop, a Red one in front and a Cream White one behind, in a photograph from VTUVIA's SX20 page.

Four colorways were orderable at VTUVIA on September 29, 2026: Teal Blue with lime rims, Red, Cream White with tan tires, and Silvery. Each ships in the same box, and our listing says it: fenders, a rear rack, a front basket and a basket bag, a set VTUVIA values at $326 on its own listing.

The Cream White SX20 with its tan-wall tires and the front basket fitted, in VTUVIA's studio photograph.

Put simply, the SX20 is a 20-inch folding fat tire bike you can step through, with a 750 W rear motor, a 672 Wh pack and hydraulic brakes, at $1,299 with the rack, fenders and basket included.

How it folds, and where it fits folded

The SX20 folds in three moves: the stem, then the frame, then the bike in half. VTUVIA's folding guide for the SX20 and SF20H lists them as "Unlock the floding stem", "Unlock and fold frame in turn", and "Fold the bike to less than half its original size", and its product page says it "shrinks down in under 30 seconds".

The Teal Blue SX20 folded: the frame hinged in the middle, both wheels side by side, and the stem folded down beside them, in VTUVIA's photograph.

Measure your trunk against the largest of VTUVIA's three folded sizes. The geometry table gives 35.4 × 20.9 × 28.3 inches (90 × 53 × 72 cm), the feature text beside it 39.3 × 28.7 × 18.9 inches, and the size chart 25.2 × 33.5 × 11.5 inches, which VTUVIA's October 2024 comparison post repeats.

Before you measure a trunk or a closet against one of them, email us, and we will ask VTUVIA which box is current and what it includes.

Folded, it still weighs 70 lb, so plan the lift before you plan the space. Take the 9.35 lb pack out first and the carry drops to about 61 lb; for a car, a hitch rack rated past 70 lb per bike saves the lift into the trunk altogether.

VTUVIA's same guide gives the storage rules for a folded bike in a garage or an RV: take the battery out for a long layup, store it at 40 to 50% charge in a cool, dry place, and top it up "every 3-4 months". It also asks you to check the folding mechanism now and then and lubricate the moving parts.

Our folding e-bike guide sets the SX20's folded box beside the other folders we sell and picks it as the mid-priced choice.

Does the SX20 fit you? Saddle, step-through and reach

VTUVIA's seat range, 30.7 to 41.7 inches from the floor, puts the saddle at the fit formula's height for 97 or more of every 100 riders from 5'0" to 5'8", for 79 of 100 at 5'10", 33 at 6'0" and 8 at 6'2"; VTUVIA sizes the SX20 for riders from 5'0" to 6'2" with a 26- to 34-inch inseam.

The cockpit is upright: with a relaxed back, the median rider leans 15 to 18 degrees off vertical and rests 14 to 17 percent of body weight on the hands, and raising the adjustable stem brings both down.

Each figure comes from placing the 6,068 people measured in the US Army's 2012 anthropometric survey on the SX20's frame, one at a time, with the saddle at 109% of each person's inseam.

Three steps find your row:

1. Measure your inseam barefoot. Stand with your back to a wall, press a hardcover book up between your legs with its spine level, and have a helper measure from the floor to the top of the spine.
2. Find your height in the saddle table and check that your inseam falls inside VTUVIA's 26 to 34 inches; past 34, read the paragraph under the table before you order.
3. Set the saddle when it arrives with the knee and heel checks in the setup answer.

VTUVIA's SX20 size guide from the product page: the arrows for the lowest and highest seat both run up from the floor line, and the two figures mark the ends of its 5'0" to 6'2" range.

Will the seat post reach my height?

For nearly everyone up to 5'9", yes; at 6'0" it reaches one rider in three, and at 6'2" fewer than one in ten. The formula sets the saddle top at 109% of inseam above the pedal axle (Peveler et al., 2005), and published work accepts 106% as a lower setting (Ferrer-Roca et al., 2012).

Turning that into a height above the floor takes three figures VTUVIA does not print, all read off its side photograph: the crank axle 12.3 inches up, a 6.9-inch crank, and a seat post leaning at 72.3° to the horizontal.

The median rider's saddle height above the floor at each height, and how many riders of 100 have their 109% and 106% settings inside VTUVIA's 30.7 to 41.7 inches; Army survey bodies, women and men together. Where the post runs out, the median rider sits about 0.6 inches low at 5'10", 0.9 at 6'0" and 1.8 at 6'2".

At full height the post matches 109% of a 34.5-inch inseam and 106% of a 35.5-inch one, so the model's top lands within half an inch of VTUVIA's own 34-inch limit. Legs longer than that meet the post's stop first, with the knee more bent at the bottom of the stroke than the formula sets it.

Over 5'10" with an inseam past 34 inches? Measure before you order. At that length the post tops out below the formula's setting, and the red flags say what to do instead.

The low end reaches further than VTUVIA's figure. The 30.7-inch minimum equals 109% of a 23.9-inch inseam, a little under the 26 inches VTUVIA recommends, so a short rider at the bottom of the window still finds the saddle low enough for the formula.

VTUVIA prints its lowest seat three ways: 30.7 inches from the floor in the product page's geometry table, 31 inches on its size chart, and 31.4 inches in its October 2024 SX20 and SF20H comparison. The table uses the geometry table's 30.7 and 41.7, the only pair that gives both ends from the floor.

Can I put my feet down at a stop?

Yes, with room to spare: at 5'0", 95 of every 100 riders clear the product page's 13.8-inch step by 13.3 inches or more. The size chart and VTUVIA's 2023 post comparing the SX20 with the SF20 give 15.4 inches instead, and VTUVIA's photograph agrees with the 15.4 (the controls table), so the table runs both published figures.

Barefoot inseam minus VTUVIA's two standover figures; each cell is the clearance that 95 of every 100 riders at that height have or beat, from the Army survey's bodies.

Sitting on the saddle is a separate question from standing over the frame. With the saddle at its lowest, 25 of every 100 riders at 5'3" can put both feet flat on the ground while seated, and 85 at 5'6", among the Army survey's bodies; the median 5'3" rider sits 0.6 inches short of flat, on the balls of the feet.

VTUVIA's rider story about CJ, who is 5'3" "with a shorter inseam", records what that felt like to her husband, Dave: "She could comfortably reach the ground with her feet and felt completely at ease on the saddle". To stop flat-footed on any bike, slide forward off the saddle onto the low step, which the SX20's frame leaves room for.

How far do I lean to reach the bars?

A modest lean, 15 to 18 degrees off vertical for the median rider at every height in the table, with the grips measured 14.5 to 18.2 inches ahead of the crank axle and 30.2 to 35.7 inches above it on VTUVIA's photograph. Twenty recreational riders in Priego Quesada and colleagues' 2017 study tried three trunk angles and rated the most upright the most comfortable.

Each lean is the smallest trunk angle at which a straight arm meets the grip from the sit bones, using the torso and arm lengths of every survey body. VTUVIA's stem is "Aluminum Alloy Adjustable", with the handlebar 45.7 to 50.4 inches off the floor on the product page; the photograph shows it near the bottom of that span, so raising it sits you more upright than the table.

How far the median rider at each height tips forward from vertical, seated mid-saddle with the stem where VTUVIA photographed it; the last column runs from the saddle's nose to its tail and across the measured grip positions.

How much weight lands on my hands?

About 14 to 17 percent of body weight for the median rider with a relaxed back; the table turns that into pounds on each hand. Carahalios, 2015 measured 15% of body weight on the bars for 10 road racers riding on the brake hoods, so at the stem height VTUVIA photographed, the model's upper bound sits close to what those racers carried.

For each height: the most of your weight the hands carry with the back relaxed, from each body's segment weights (Clauser et al., 1969), turned into pounds at the survey's median weight; the bracket spans the saddle and grip positions.

Sore palms after a ride? Raise the stem first. Higher grips tip the trunk back and move weight onto the saddle, and across 36 riders in Slane et al., 2011, padded gloves lowered pressure over the ulnar nerve by 10 to 28%.

How do I set the saddle when it arrives?

Set it so the knee keeps a bend of 25 to 35 degrees with the pedal at the bottom of the stroke (Peveler et al., 2007). The fastest first pass is the heel check: heel on the lowest pedal, then raise the saddle until that leg just straightens.

In Peveler et al., 2005, the heel check put 70% of 19 trained cyclists inside that knee range, more than either inseam formula did. With the SX20 on its kickstand, loosen the seat clamp, slide the post to your height, and tighten the clamp hard before you ride. For a softer ride, the VTUVIA suspension seatpost in its CMB/SX20 fitting adds 50 mm of travel on a 350 mm post, $129 on our store.

The fit arithmetic

Three rules run the section. Saddle: 1.09 × inseam above the pedal axle. Lean: the smallest trunk angle at which a straight arm meets the grip. Hand load: the upper body's weight times its lean, divided by the reach to the grip.

Worked for a 5'8" rider: the survey's median inseam at 5'8" is 32.6 inches, and the formula asks for 35.6 inches from the pedal axle, which is 28.6 inches above the crank axle once the crank is taken off and 39.8 inches from the floor, inside the post's 41.7.

LeMond's rule lands close to it. Its 88.3% of inseam from the crank axle gives 28.8 inches for that rider, which comes to 109.7% of inseam from the pedal once the measured crank is added, inside the 109.2 ± 0.9% Peveler and colleagues report for their riders.

The crank, the crank axle, the post angle and the grips come from VTUVIA's Teal Blue side photograph, scaled by the size chart's 45-inch wheelbase between the axle centers, after the photograph was checked against VTUVIA's own lengths:

Four of the size chart's five lengths match the photograph within 3.5%: the chainstay, the standover, the wheel and the head tube, one more than the three the method requires. On the product page's 46.9-inch wheelbase every measured length would read 4.2% longer, and the crank and crank-axle brackets in the inputs table carry that scale.

The motor: 750 W in the rear hub, 1,200 W at peak

VTUVIA rates the SX20's rear hub motor at 750 W, with a 1,200 W peak, fed by a 48 V 25 A controller; 48 volts at 25 amps is where the 1,200 W comes from.

The torque is 85 N·m in the specification table and in the FAQ, and 80 N·m in the description on VTUVIA's product record; plan on the table's figure, and read the 750 W against the definitions in the class section.

A hub motor turns the rear wheel itself, so its push does not depend on which gear you are in. Our e-bike motor guide sets hub motors beside mid-drives, and the gear table shows what your own pedaling saves on this one.

The assist changes how it reads your pedaling with the road. VTUVIA's page calls the system "V-Adapt™": "When the road tilts up, V-Adapt™ immediately prioritizes torque sensing", and "On flats, the system transitions to cadence sensing". The specification table lists a "Torque Sensor", and the highlight strip names both, "Torque & Cadence Sensors".

Pedal assist comes in "3 Modes x 5 Levels", and a thumb throttle moves the bike with no pedaling at all. VTUVIA's FAQ puts the top speed at "up to 20MPH with both throttle and pedal assist", which is where every table on this page stops.

The battery: 48 V × 14 Ah = 672 Wh of LG cells

The pack is 48 volts and 14 amp-hours, 672 watt-hours, built from LG cells, and it runs the motor, the lights and the display. The specifications page gives the same 48 V and 14 Ah and weighs the pack at 9.35 lb.

The SX20's pack on its own in VTUVIA's product image: a long black case with a round fitting at one end.

VTUVIA's specifications page calls the pack removable, so it can charge indoors while the bike stays folded in a car, a garage or an RV bay. Our replacement key set for the SX20, cut to your lock number, is $89, and a spare 48 V 14 Ah pack for the SX20 is $599 on our parts shelf, charger not included.

The 2 A charger delivers about 109 W. At VTUVIA's 54.6 V and 2 A, 672 Wh takes about 6.2 hours before charger losses; the product page says "About 7 Hours" and the specifications page 5 to 6, so leave 7. A second VTUVIA 2 A charger in the SX20's fitting is $99, for a charger at home and one at the other end.

How far the SX20 goes: range by speed, hill, load and cold

Count on about 37 miles from a full pack at 15 mph on the throttle with 180 lb aboard on level ground, about 26 at 20 mph, and about 56 at 15 mph if you pedal easily. Up a steady 8% grade at 10 mph on the throttle alone, the same charge lasts about 9 miles.

Find your own figure in three steps:

1. Pick your usual speed and how hard you pedal from the speed tables.
2. Add the climbing: each 1,000 feet of gain at 10 mph on the throttle costs 136 Wh on a 4% grade and 161 Wh on a 10% grade, less with pedaling (the hills table).
3. Adjust for your weight and cargo and the air temperature, then plan on 75% of the pack.

The model works out one steady ride at a time, built from VTUVIA's specification, a comparable hub motor's published figures, ten fat tires measured on a drum, and a cycling-power model validated against riding on an open road. The formula subsection works one ride through and compares the model with a measured ride.

Does speed cut the SX20's range? Miles at each speed

Faster costs miles fast: from about 51 miles at 10 mph on the throttle to about 26 at 20 mph. The step from 15 to 20 mph alone takes the full charge from 37 miles to 26.

Air resistance does most of that. The drag force grows with the square of your speed and the power to beat it with the cube, so every extra mile an hour at the top of the range costs more than the one before it.

Throttle only, level ground, a 180 lb rider, 77 °F air; the table stops at VTUVIA's 20 mph. The last column keeps a quarter of the pack back, since researchers at KIT found 75% of the pack used on one measured pedelec over a standard range test (Schmitt, Decker and Doppelbauer, 2019).

Add about 75 W of easy pedaling at 15 mph and 37 miles becomes 56. In these tables 75 W is easy and 150 W is steady. To place yourself, picture the SX20 on the flat with its motor off: 75 W from your legs would hold about 9.1 mph and 150 W about 13.2 mph, and the column nearest your unassisted pace is yours.

Full-charge miles on the level with 180 lb aboard. At 15 mph the pack spends 18.1 Wh a mile when the motor does it all and 12.1 Wh when you pedal easily. Trust the 104-mile cell least: at that point your legs out-work the motor, and the model's motor losses at so light a load have no published check (Limitations, item 5).

The number on the assist display does not set these figures on its own. What the pack pays for is the speed you hold and how much of the work you leave to the motor; VTUVIA's range note lists "the rider's weight, pedal assist level, throttle use, terrain, speed, weather, and towing weight".

Do gears or pedaling save battery on the SX20?

Pedaling saves battery; shifting on its own does not. The motor sits in the rear hub, outside the chain, so a gear change alters how fast your legs spin and leaves the motor's share where it was. At a given speed and grade, only more of your own effort lightens what the pack supplies:

Pack watt-hours per mile at 77 °F with 180 lb aboard; your legs add 75 W in the easy column and 150 W in the steady one.

Use the seven Shimano gears to keep your legs turning at a comfortable pace, and shift down before a stop or a climb so the restart is light. On a grade, your effort is what moves the numbers, as the hills table shows.

How much battery does a climb cost?

Each 1,000 feet of climbing costs 136 to 161 Wh at 10 mph on the throttle, on grades from 4 to 10%, and 126 to 147 Wh with easy pedaling. Of that, 94 Wh goes into lifting rider and bike at the rear wheel; the rest leaves the motor and the pack as heat.

A 180 lb rider on the 70 lb SX20 makes 250 lb. On the throttle up an 8% grade at 10 mph, each 1,000 feet costs 150 Wh, so a full 672 Wh pack covers about 4,500 feet of climbing and nothing else. The model recovers nothing on the way down, which keeps these figures on the cautious side.

Each row holds 10 mph with 180 lb aboard. The watt-hours and the throttle miles leave your legs out; the easy-pedaling column puts 75 W of yours back in. The last column is the quickest pace the motor holds up that grade by itself, inside the 750 W rating and 1,200 W peak and never above 20 mph.

On a 15% ramp, pedal. The throttle alone holds about 8.5 mph there, and 75 W from your legs lifts it to about 10.0 mph; on 12% the same effort takes the throttle's 11.6 mph to about 13.0.

Put the climbing on top of the flat miles. Ten level miles at 15 mph on the throttle take about 181 Wh, and a 300-foot climb at 6% adds about 43 Wh, 224 Wh together, a third of the pack. Headwinds, stops and soft ground come on top, since the model rides one steady speed.

How much does a heavier rider or a full rack cost?

On the flat, extra weight costs a few miles; uphill it costs a lot more. Each added pound presses the tires harder into the road and has to be lifted on every grade, while the air's drag does not change, so the gap between light and heavy widens as the road tips up. To the pack, groceries on the rack weigh the same as a heavier rider.

The rider plus everything carried, with the bike's 70 lb added to every row; throttle only. The last row, 330 lb, is as much as VTUVIA rates the SX20 to carry.

A 190 lb rider with 40 lb of shopping on the rack is the 230 lb row: 35 flat miles at 15 mph, or about 7 miles of steady 8% climbing at 10 mph. At the full 330 lb, the 15 mph flat figure falls from 37 miles to 30, about a fifth less, and each climb costs more again (the hills section).

How much range does the cold take?

Colder air, shorter rides. A 15 mph throttle ride good for 37 miles on a 77 °F afternoon shrinks to about 30 at freezing, 32 °F, and about 27 at 14 °F.

Level ground, 180 lb aboard. Each central figure comes from McMaster University's tests of an LG HG2 cell at 77, 50, 32 and 14 °F, recomputed for a 0.5C discharge, with the rows between interpolated and the cells assumed to sit at the air's temperature. VTUVIA names LG cells; the HG2 stands in as an LG cell with published cold-weather data.

The brackets come from other published cells. Low end: the smallest capacity a Samsung data sheet gives at that temperature for a one- to four-hour discharge (25R and 30Q at 32 °F, 35E at 14 °F). High end: the most energy Casado and colleagues measured in 2025 at a slower discharge.

Three things shrink the ride below freezing. At 32 °F the cells give back about 89% of their 77 °F energy (80 to 93%, depending on the source), and the air is about 9% denser under the gas law used in the U.S. Standard Atmosphere, so each mile pushes more of it aside.

Cold rubber rolls harder, too. The model adds 0.5% to rolling resistance for every °F below 77 °F (0.9% per °C), between Rothhämel's fit for a 42 mm tire and Bicycle Rolling Resistance's road-tire average, and stops adding below 41 °F. On a winter morning, keep the pack indoors overnight and slide it in just before you leave.

A hot day works the other way. At 95 °F the cells hold 99% of their energy, but the air is about 3% thinner and the same rule takes about 9% off the tires' rolling resistance, so the 15 mph throttle ride gains a mile or two over 77 °F.

Do the fat tires cost range, and does posture matter?

The tire decides more than your posture does. Bicycle Rolling Resistance's drum ran ten 26 × 4.00 fat tires at 18 mph, 12 psi and a 94 lb load, and they took between 23.2 and 42.1 W each.

No 20 × 4.0 tire like the SX20's is on that drum list, so the model rolls on the median of the ten, a coefficient of 0.0105, and brackets it with the lowest and the heaviest-rolling tire.

Level ground, 180 lb aboard, a full pack. The slow bracket is the Kenda Juggernaut Pro, measured at 0.01262 on its own drum page.

Keep the tires at the pressure molded on the sidewall; the drum figures above were taken at 12 psi. Posture matters more as speed rises. The model uses the 0.640 m² drag area Tengattini and Bigazzi measured on 37 riders of upright cruisers; tuck to the 0.603 m² of their 90 mountain-bike riders and the 20 mph throttle ride grows from 26 miles to 28.

VTUVIA's 70, 40 and 52 miles, as steady rides

Each of VTUVIA's range figures matches a steady ride the model can name. The product page lists 70 miles on pedal assist and 40 on the throttle only, and the specifications page lists 52 miles on the same 14 Ah pack.

The level-ground speed that would use all 672 Wh over VTUVIA's distance with a 180 lb rider: 70 miles means 9.6 Wh a mile, 40 miles 16.8 and 52 miles 12.9. A dash means no steady speed between 5 and 20 mph fits: on the throttle alone the model never gets down to 9.6 Wh a mile, and with 150 W of pedaling it stays under 16.8 all the way to 20 mph.

So VTUVIA's 70 miles is easy pedaling at about 13.4 mph, its 40 on the throttle is a steady 13.9 mph, and its 52 is the throttle at a slow 9.5 mph or easy pedaling at about 15.6. At 15 mph on the throttle, the model's 37 miles lands just under VTUVIA's 40.

Plan on three-quarters of the miles in your row. That quarter is what the KIT test bench left unused in its pack, which makes the planning figure 28 of the full 37 miles at 15 mph on the throttle.

The range formula, worked through

One equation sits under every figure above. Martin and colleagues' 1998 model, validated against power measured on an open road, turns speed, weight, slope and air into the power the rear wheel needs to hold a steady speed in still air:

P = v × [ m × g × (Crr × cos θ + sin θ) + ½ × ρ × CdA × v² ]. P is what the rear wheel has to put down.

In it, v is road speed, m the mass of rider, cargo and bike, g gravity, θ the slope's angle, Crr the tires' rolling-resistance coefficient (0.0105 is a drag of 1.05% of the weight on the tires), ρ the air's density, and CdA the drag area, the size of the hole you punch through the air (Martin et al.).

From the wheel back to the pack, the power passes four stages:

1. Your legs: 97.7% of what you put into the pedals reaches the rear wheel through the chain (Martin and colleagues' chain efficiency), and the motor supplies the rest.
2. The rear hub carries the motor's whole share.
3. The motor is modeled on a comparable hub whose maker publishes its figures: Bafang's 2021 OEM workbook gives the RM G062.750.D/DC 400 rpm unloaded and 350 rpm at its rating on 48 V, with 85 N·m and an efficiency of "≥ 80" percent. Here the model keeps 80% at the rated point, lets efficiency drop as the load lightens, and limits torque to VTUVIA's 85 N·m and the pack's draw to the 1,200 W peak.
4. The cells warm up as they discharge, and the model charges that loss at the rate Arango, Lopez and Ceren measured on a 48 V pack.

From there it takes two divisions: Wh per mile = pack watts ÷ mph, then range = 672 Wh × the share of the cells' energy left at that temperature ÷ Wh per mile.

The 37-mile ride, worked through step by step: 180 lb on the bike, a level road, 15 mph, the throttle doing all of it. Holding it takes 192.8 W at the rear wheel, 78.6 W for the tires and 114.2 W for the air.

At that speed the 23-inch wheel turns 219 times a minute and needs 8.4 N·m. The motor model, built from Bafang's published figures as 1.146 N·m per amp, a 0.307 Ω winding and 1.67 A with no load, supplies that on 9.0 A at 74% efficiency, taking in 261.8 W.

Counting the pack's internal losses, the cells supply 271.5 W; at 15 mph that is 18.10 Wh a mile, and 672 Wh at 18.10 Wh a mile runs about 37.1 miles, or 27.8 once a quarter of the pack is kept back.

Two published figures come back first. Before it computes a ride, the model reproduces both:

The self-test reruns Appendix I of Martin and colleagues (8.36 m/s, a 90 kg system, a 0.3% grade) and the RM G062.750.D/DC's rated point from Bafang's workbook, and stops if either misses.

A measured ride on the SX20's sibling. No SX20 run to an empty pack appears in the reviews read for this page, so the nearest measurement is Electric Revolution's range test of VTUVIA's SF20, posted August 9, 2022: the same class of 750 W rear hub on 20 × 4.0 tires, with a smaller 624 Wh pack.

On "flat terrain" at 20 mph he covered 21.16 miles with 790 feet of climbing and stopped with "two battery bars left", estimating "24-25 miles" in all. The model, run with the SX20's inputs on a 624 Wh pack, gives 24.6 miles at 20 mph on the level, and the 790 feet would cost another 107 to 127 Wh on the throttle.

His second run, with "a lot more stop and go", reached 23.73 miles with 4,275 feet of gain; at the model's climbing rates that much climbing alone would use 93 to 110% of a 624 Wh pack, so his pedaling and the descents carried part of it.

Read both runs as a check on the order of magnitude and nothing finer: a different bike, a rider whose weight is not given, and a first run that ended with charge left.

Brakes, display and lights

Both wheels stop on "Dual LOGAN Hydraulic Disc Brakes" over 180 mm stainless rotors, and VTUVIA's page sells them as "strong and responsive braking power". Replacement hydraulic pads with the SX20 in their fitment were $25 a pair on our pad listing on September 29, 2026.

The display is a 3.5-inch full-color screen with an adjustable angle, and VTUVIA's feature text says it lets you "See speed, battery, and pedal assist clearly in any lighting condition".

The display in VTUVIA's product image, with speed in the middle, the charge level on top and the assist level at the bottom right; the plus, power and minus buttons sit on a pad by the left grip.

Lighting is a "48V 10W 150 Lux LED Headlight & Brake Light". There is no bell or horn in the box, so add one if your streets or paths call for it.

The headlight lit on a Silvery SX20 after dark, in VTUVIA's photograph; VTUVIA rates it at 10 W and 150 lux.

Fork, tires, gears and water

The front fork is an EXSHO suspension fork, which the feature text calls a "Hydraulic Front Fork" that "Absorbs bumps and rough roads for a smoother, more comfortable ride with less fatigue".

The suspension fork on a Cream White SX20 in VTUVIA's close-up, with the yellow label on the lower leg and the 20 × 4.0 tire behind it.

The tires are 20 × 4.0, "CHAOYANG Anti-puncture Reflective" on the specifications page, and the gearing runs a Shimano TX50 shifter and TY300D derailleur over a TZ5007 seven-speed cassette of 14 to 28 teeth. For spares, our VTUVIA parts shelf had a 20 × 4.0 tube at $39 and a 20-inch reflective fat tire at $79 on September 29, 2026.

On water, VTUVIA's class note sets the limits. The SX20 "is built to the IP67-rated standard, making it suitable for riding through creeks, mud, and snow", but VTUVIA asks you to "avoid prolonged or intentional immersion in water", and says the bike "is not designed to withstand high-pressure sprays". Ride through the puddle, then wipe the bike down with a damp cloth rather than a hose on full.

Weight, load and the rack

The SX20 weighs 70 lb on both of VTUVIA's pages, "include rear racks and fenders" on the product page and "battery included" on the specifications page. Lift it with the pack out when you can, which leaves about 61 lb, and check a hitch rack's per-bike limit against the full 70.

Keep you and everything you carry under 330 lb. That is the SX20's "Total capacity" on the product page and its "Max Load" on the specifications page, and the feature text repeats it: "This product can handle up to 330 lbs".

Load the rear rack to 55 lb. VTUVIA's rear rack listing rates its rack "For VTUVIA E-bikes (New SN100, New SJ26, SX20, Reindeer, and Gemini)" at "25 kg (55 lbs)", and the product page gives the rack's platform as 15.7 × 5.9 inches.

The rear rack's spring clamp lifted by hand in VTUVIA's close-up, with the red light at the rack's tail and the ANTELOPE lettering on the seat stay.

The front basket in the box takes the lighter things, and our VTUVIA accessories add a 55 lb rear rack in the SX20 fitting at $99 and an aluminum front basket at $89 if you need a second of either.

The Mercer fit test

Every bike we review meets the same seven people, the Mercers of Fair Oaks, California, so the fit questions stay the same from one review to the next (meet the Mercers). Each verdict rests on a figure VTUVIA publishes (its 5'0" to 6'2" window, the 26 to 34 inch inseam, the 330 lb capacity, the FAQ's age line), on the fit tables, or on the California code sections named in the row.

Frank, Ruth, Dana and Maya fit, and the three women can sit flat-footed at the lowest saddle more often than not. Jack, at 6'1", is where the post runs out first, and Cole fits the frame but sits right at VTUVIA's age line.

A Red SX20 parked by a lake, in an owner's photograph VTUVIA shows on its product page, credited @Graham De Looze.

Has it been recalled?

No. On September 28, 2026 we searched the Consumer Product Safety Commission's recall data for VTUVIA, Vtuvia and vtuviaebike by title, product name and manufacturer, then read every field of all 623 of its bicycle, e-bike, battery and scooter recall records for the brand and for the names SX20 and Antelope.

No record names VTUVIA or the SX20. The same search first had to find brands with known recalls, and it found 1 for Ancheer, 54 for Specialized and 24 for Trek, which is why its silence here counts.

The class question: 750 W rated, 20 mph as delivered

The SX20 leaves VTUVIA as Class 2: pedal assist and a thumb throttle, both "up to 20MPH", on a motor rated at 750 W with a 1,200 W peak. VTUVIA's class note says it "comes out of the box as a Class II e-bike, equipped with pedal assist and throttle", and the watt figure is read on its own, apart from the speed.

The federal consumer-product definition in 15 U.S.C. § 2085(b) covers a low-speed electric bicycle with "fully operable pedals and an electric motor of less than 750 watts (1 h.p.)", whose top speed on motor power alone, with a 170-pound rider, "is less than 20 mph".

California sets its line in other words. Under Vehicle Code § 312.5(a), read on September 28, 2026, an electric bicycle is "a bicycle equipped with fully operable pedals and an electric motor that does not exceed 750 watts of power".

So a 750 W rating falls on opposite sides of the two texts. A 750 W motor is not "less than 750 watts", yet it does not "exceed 750 watts" either. Neither text says whether the rated or the peak figure is the one measured, and VTUVIA prints both.

The texts are § 2085(b) and § 312.5(a) as they read on September 28, 2026, set against the figures on VTUVIA's SX20 page.

The federal text governs how the Consumer Product Safety Commission treats the product; where and how you ride is your state's call, and states word the watt line several ways. Our 50-state e-bike law atlas quotes each state's definition, and our California page goes further into the state quoted here. Bike paths, parks and trails set their own rules on top, so check the sign or the managing agency before you ride one.

Campgrounds, trails and federal land

On federal land, the agency's own definition and route map decide where the SX20 may go, whatever its class. If it travels folded in an RV bay or a trunk to a trailhead, find out who manages the ground before you unfold it.

Each row is settled by the land manager's own document, whichever bike you bring.

On Bureau of Land Management land, 43 CFR 8340.0-5(j) defines an e-bike as "a two- or three-wheeled cycle with fully operable pedals and an electric motor of not more than 750 watts (1 h.p.)" in one of three classes; the SX20's 750 W rating meets "not more than 750 watts" and its 1,200 W peak is over it, the same split as California's line above.

Paragraph (a)(5) of the same section leaves an e-bike out of the off-road vehicle rules only when three things hold together: a road or trail "upon which mechanized, non-motorized use is allowed", a motor that is not "exclusively propelling the e-bike for an extended period of time", and a field office that "has expressly determined" e-bikes should be treated the same as non-motorized bicycles.

Where any of the three is missing, the SX20 counts as an off-road vehicle, with the penalty that carries. Under 43 CFR 8340.0-7, breaking the off-road rules of subparts 8341 and 8343 can bring "a fine of not more than $1,000 or imprisonment for not longer than 12 months, or both". A long stretch on the thumb throttle alone fails the second condition even where the other two hold.

National Forests take a stricter line. The Forest Service's notice at 87 FR 41278 says its final directives provide for "managing all classes of e-bikes as motor vehicles", and once a district's motor vehicle use map is out, 36 CFR 261.13 bars operating a motor vehicle there "other than in accordance with those designations". Our public-land e-bike guide takes the federal agencies one at a time, national parks and wildlife refuges included.

Green flags / Red flags

Green flags

• A low step and a post that suits short riders: a 13.8- or 15.4-inch step, and a seat post that reaches the saddle setting for 97 or more of every 100 riders from 5'0" to 5'8".
• Folds in three moves, stem then frame, and VTUVIA says in under 30 seconds.
• A 750 W rear hub with a 1,200 W peak and VTUVIA's V-Adapt assist, which leans on torque sensing uphill and cadence sensing on the flat.
• 20 × 4.0 tires, an EXSHO fork and LOGAN hydraulic brakes on 180 mm rotors, with seven Shimano gears.
• A computed 37 flat miles at 15 mph on the throttle for a 180 lb rider, and 56 with easy pedaling.
• Fenders, a rear rack and a front basket in the box, with a 150 lux headlight and a brake light.
• $1,299, VTUVIA's own price, with the SX20's charger ($99), pads ($25), spare pack ($599) and suspension seatpost ($129) on our shelf.

Red flags

Each one is about fit: who the SX20 is wrong for, and what to do instead.

• Wrong for riders past about 6'0" with an inseam over 34 inches who want the saddle where the formula puts it; send us your height and inseam, and we will suggest a taller frame we sell.
• Wrong if you want to carry a passenger. The SX20 has no rear seat; the VTUVIA SF20H folds too and carries a padded rear seat and foot pegs on a welded rack.
• Wrong if the rack has to carry more than 55 lb. VTUVIA rates it at 55 lb; carry the rest in a backpack, or email us and we will match a cargo bike we sell to the load.
• Wrong if rider and cargo together pass 330 lb. That is VTUVIA's capacity on both pages; email us your total, and we will match a bike rated for it.
• Wrong if it has to be lifted into a car alone every day. It is 70 lb, or about 61 with the pack out; the Eunorau META20 folds and steps through at 63.4 lb, and our folding guide compares the folders we sell by folded size and gives each pick's weight.
• Wrong where the state definition says "less than 750 watts". At a 750 W rating the SX20 sits on that line; look up your state's words in the law atlas before you buy.
• Wrong for paths that admit Class 1 bikes only. The thumb throttle makes the SX20 Class 2; name the path in an email and we will check its rule.

Buy it if / Buy something else if

Buy it if you want a folding fat tire bike you can step through and stop on with your feet down, with a 750 W motor, a 1,200 W peak, a 672 Wh pack and hydraulic brakes, at $1,299. It computes to 37 miles at 15 mph on the throttle for a 180 lb rider, and it folds small enough for a trunk or an RV bay.

It suits riders inside VTUVIA's 5'0" to 6'2" window, and above all those from 5'0" to about 5'9", whose saddle setting the post reaches for nearly everyone, with a total load under 330 lb and a rack load under 55 lb.

For $1,299 you get a 750 W rear hub motor with a 1,200 W peak, 85 N·m on the specification table, a removable 672 Wh LG pack, an EXSHO fork, LOGAN hydraulic brakes, seven gears, a color display, lights, fenders, a rack and a front basket. On our listing's Shop Pay plan that comes to $117.25 a month for 12 months at 15% APR, $1,407.00 in all.

Buy something else if you want to carry a passenger, need more than 330 lb of capacity, or stand over 6'0" with a long inseam: the SF20H folds and seats two, and for the other two, the red flags point to what to do.

Every review we have published sits on our e-bike reviews hub, and our 750 W buying guide compares the bikes we sell at this rating.

A Silvery SX20 at the edge of a wooded paved trail with its owners, in a photograph VTUVIA shows on its product page, credited @Harvey Winkler; the trunk bag and phone mount are the owners' own.

Before you buy: the checklist

Run through these ten before you spend $1,299; where you will ride comes first.

1. Find where you may ride: your state's e-bike definition, then the posted rules for each path or trail you use.
2. Set the SX20 against those rules: VTUVIA rates the motor at 750 W and ships the bike as Class 2 at 20 mph.
3. Measure your inseam and read your row of the fit tables: the saddle table, VTUVIA's 26-to-34-inch range, and the flat-foot figures.
4. Check your height against VTUVIA's 5'0" to 6'2", and read your saddle row closely if you are over 6'0".
5. Weigh yourself with your cargo and keep the total under 330 lb.
6. Keep the rack under 55 lb, and put the lighter things in the front basket.
7. Measure the trunk, closet or RV bay against the largest of VTUVIA's three folded sizes, and ask us which is current.
8. Plan the lift: 70 lb, about 61 with the pack out, and a hitch rack rated for the full weight.
9. Look up your usual ride in the range tables, then add hills and cold and hold back a quarter of the charge.
10. If your building, your city or a rebate program asks for a certification, email us before you order and we will ask VTUVIA for the documents in writing.

Buying it from us

Why buy the SX20 from Redtail

On September 29, 2026 our listing priced every SX20 colorway at $1,299 against a regular $1,599, the same as VTUVIA's page that day.

The Red SX20 in VTUVIA's studio photograph, one of the four colorways at the same $1,299.

Returns for a change of mind follow the refund policy's own terms: ask within 72 hours of delivery with the bike still sealed in its factory packaging, and the refund comes less a 15% restocking fee and the return shipping; canceling an order costs a 3% transaction fee. Questions about fit, range, folding or the rules where you ride cost nothing, so send them before you order.

Frequently asked questions

How far can the VTUVIA SX20 go on one charge?

VTUVIA lists 70 miles on pedal assist and 40 on the throttle (its specification), and 52 miles on its specifications page. If you weigh 180 lb and ride on the level, the model puts you at about 37 miles at 15 mph on the throttle, 26 at 20 mph and 56 at 15 mph with easy pedaling; every 1,000 feet of climbing at 10 mph on the throttle takes 136 to 161 Wh more (range).

What is the top speed of the VTUVIA SX20?

VTUVIA's FAQ says "The SX20 can reach speeds of up to 20MPH with both throttle and pedal assist", and its class note calls it "a Class II e-bike" out of the box. Every table on this page stops at 20 mph for that reason (the class section).

Is the VTUVIA SX20 street legal, and which class is it?

It ships as Class 2, as VTUVIA delivers it: pedal assist and a thumb throttle, both to 20 mph. On the watt line, 750 W meets California's "does not exceed 750 watts" but sits on the federal "less than 750 watts" line rather than under it, and where you may ride it is up to your state (the class section).

How much does the VTUVIA SX20 weigh?

VTUVIA prints 70 lb "include rear racks and fenders", and its specifications page gives the same 70 lb "battery included", with the pack itself at 9.35 lb. Take the pack out and you lift about 61 lb (the weight section).

How much torque does the VTUVIA SX20 have?

85 N·m in VTUVIA's specification table and FAQ, which pairs it with the motor's 1,200 W peak; the description on VTUVIA's product record says 80 N·m. The range model caps the motor at 85 N·m (the motor section).

Does the SX20 have a torque sensor?

Yes. VTUVIA's specification lists a "Torque Sensor", and its V-Adapt system "immediately prioritizes torque sensing" when the road tilts up and "transitions to cadence sensing" on the flat, which is why the highlight strip says "Torque & Cadence Sensors" (the motor section).

How small does the SX20 fold?

VTUVIA gives three folded sizes: 35.4 × 20.9 × 28.3 inches in the product page's geometry table, 39.3 × 28.7 × 18.9 inches in its feature text, and 25.2 × 33.5 × 11.5 inches on its size chart. Measure your space against the largest, and email us to find out which is current (folding).

What height rider does the VTUVIA SX20 fit?

VTUVIA's page sizes it for riders from 5'0" to 6'2" with a 26- to 34-inch inseam. The post reaches the formula's saddle height for 97 or more of every 100 riders from 5'0" to 5'8", 79 at 5'10" and 33 at 6'0", so if you are a shorter rider it fits you well; if you are tall, measure your inseam first (fit).

How much weight can the SX20 carry?

330 lb in total, you plus everything on the bike, on VTUVIA's product page and its specifications page. The rear rack takes 55 lb on VTUVIA's rack listing, and at the full 330 lb your flat 15 mph throttle ride comes to about 30 miles (the weight table).

How long does the SX20 battery take to charge?

Allow about 7 hours: VTUVIA's product page says "About 7 Hours", and its specifications page 5 to 6. The 54.6 V, 2 A charger supplies about 109 W, so your 672 Wh pack needs about 6.2 hours before charger losses (the battery section).

Can I buy a spare or replacement battery for the SX20?

Yes. VTUVIA's 48 V 14 Ah battery for the SX20 is $599 on our store, charger not included, and a second 2 A charger in the SX20's fitting is $99. Send us a photo of your pack's label, and we will confirm the match before you pay.

Can I carry the SX20 on a car rack or in a trunk?

Yes, either way, if the rack or the trunk is big enough for it. On a hitch rack, check the per-bike limit against the full 70 lb; for a trunk, fold it and measure against the largest of VTUVIA's three folded sizes, and lift it with the 9.35 lb pack out (folding).

Can you ride the SX20 in the rain?

VTUVIA's class note says it "is built to the IP67-rated standard, making it suitable for riding through creeks, mud, and snow", while asking you to "avoid prolonged or intentional immersion in water" and to keep pressure washers and sprayers off it (VTUVIA's page). Ride in the wet, then wipe it down (the water section).

What does the VTUVIA SX20 cost to run?

About 18.1 Wh a mile at 15 mph on the throttle for a 180 lb rider, so a full charge is 0.672 kWh from the wall before charger losses; multiply that by the rate on your electric bill. The parts you are most likely to replace, pads and tubes, are $25 and $39 on our shelf (the gear table).

How is the SX20 different from the SF20H?

Both are VTUVIA folders with a 750 W rear hub, a 672 Wh pack and 20 × 4.0 tires, and both were $1,299 on our store on September 29, 2026. The SF20H carries a padded rear seat and foot pegs on a welded rack for a passenger; the SX20 steps through lower, at 13.8 or 15.4 inches against the SF20H's 16, and its box includes a front basket.

What warranty does the VTUVIA SX20 have?

Buy it from us and we are the ones you contact about a fault: email photos and your order number, and we run the claim to the end. If the bike won't power on or charge, shows an error code or has a faulty component, our refund policy says "we coordinate repair or replacement remotely". Email us before you order and we will put the terms for your bike in writing.

Is the VTUVIA SX20 worth it?

For $1,299 on our store (regular $1,599, read September 29, 2026) with free contiguous-US shipping, you get a folding step-through fat tire frame, a 750 W motor with a 1,200 W peak, a 672 Wh pack, hydraulic brakes, and a rack, fenders and basket in the box. It suits you best if you stand 5'0" to about 5'9" and want a bike that folds away (the verdict).

Can I finance the VTUVIA SX20?

Yes. Shop Pay on our listing, read September 29, 2026, splits the $1,299 SX20 into 12 monthly payments of $117.25 at 15% APR, $1,407.00 altogether, and offers 3- and 6-payment plans at that APR too.

Limitations of this review

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

1. We sell this bike. Give the red flags as much weight as the green.
2. This review is specification-verified. Its figures come from VTUVIA's published pages, statutes, our own store record, the published research the range and fit sections cite, or arithmetic on this page.
3. Each range figure is one steady ride: a single speed on a single grade, with no wind and no stops. Starts, stops, headwinds and soft ground cost more.
4. Bafang's figures stand in for VTUVIA's motor. VTUVIA publishes the rating, the peak, the torque and the controller, and the documents read here do not name the motor's maker or its internals. At 82% efficiency instead of Bafang's 80% floor, the 15 mph throttle figure rises from 37 miles to 39, and the 20 mph figure from 26 to 28.
5. At light motor load the model has no measured check. Where your legs do more of the work than the motor, as in the steady-pedaling column at 15 mph, the result rests on motor losses no published hub-motor map could confirm.
6. The rated-power reading is the model's. If VTUVIA's 750 W sat on a comparable motor rated at 1,000 W, the 15 mph throttle ride would come to 36 miles and the 20 mph ride to 26.
7. The steep rows assume the controller delivers the full 1,200 W its 48 V and 25 A allow. A controller that delivers less holds a slower speed on a steep grade than the hills table shows.
8. The measured ride is on the SF20, the SX20's sibling with a 624 Wh pack; the rider's weight is not given, and the first run ended with charge left. The video is a reviewer's recorded day: its description says "I do receive a small commission". No SX20 range run to an empty pack was found in the reviews and videos read for this page.
9. Every figure assumes VTUVIA's 672 Wh. The documents read here do not say how much of the pack the battery management releases; the planning column keeps back the quarter researchers at KIT found unused on one measured pedelec.
10. The tire coefficient comes from 26 × 4.00 fat tires. The drum list holds no 20 × 4.0 tire like the SX20's, so the model takes the median of ten 26-inch fat tires at 12 psi and brackets it with the lowest and the heaviest-rolling.
11. The cold figures rest on one cell's laboratory data. VTUVIA names LG cells without a cell model, so the central line uses McMaster University's measured LG HG2 cell, bracketed by other published cell data.
12. The wheel is the size chart's 23 inches. The tread circles on VTUVIA's photograph read 22.8 inches at the size chart's wheelbase and 23.8 at the product page's, and across all three the 15 mph throttle figure stays at 37 miles.
13. VTUVIA prints two torque figures, 85 N·m in the specification table and FAQ and 80 N·m in the product record's description; the model caps torque at 85.
14. VTUVIA prints two range sets, 70 and 40 miles on the product page and 52 on the specifications page, for the same 14 Ah pack; the range section maps all three.
15. VTUVIA publishes two charge times, "About 7 Hours" and 5 to 6 hours; the page plans on the longer.
16. VTUVIA prints three folded sizes, and none of the pages read here says which is current or what each includes.
17. VTUVIA prints two sets of lengths with two wheelbases, 46.9 inches on the product page and 45 on the size chart. The photograph was scaled at 45, the set it matches, and the measured crank and crank axle are bracketed by the 46.9.
18. Four fit inputs are measured, not published: the crank length, the crank axle's height, the seat post's angle and the grip position come from VTUVIA's side photograph, each with a bracket.
19. The lean and the hand load are read at the stem height VTUVIA photographed. The stem adjusts, and raising it lowers both below the tables.
20. The flat-foot figures set a barefoot inseam against the saddle's top height. Shoes, the saddle's width and leaning the bike all change what you feel at a stop.
21. 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.
22. 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 70%, so let the knee and the heel set the final height.
23. VTUVIA prints its lowest seat three ways, 30.7, 31 and 31.4 inches; the model uses the geometry table's 30.7 to 41.7, the only pair given from the floor at both ends.
24. The SX20 pages read here print no certification line. VTUVIA's SF20H page lists UL 2849 for that model; for the SX20, email us and we will request VTUVIA's documents in writing.
25. The recall search covers the CPSC's US database under the names listed; a recall filed under another company's name would need that name searched.
26. The price, the colorways and the stock were read on September 29, 2026, and each can change, as can VTUVIA's stock, our parts prices and the Shop Pay terms.

The bottom line

At $1,299, the SX20 puts a 750 W rear hub motor with a 1,200 W peak and a 672 Wh LG pack on a folding step-through frame, with 20 × 4.0 tires, an EXSHO fork, LOGAN hydraulic brakes, seven gears, and a rack, fenders and basket in the box.

For a 180 lb rider the model computes about 37 flat miles at 15 mph on the throttle, or 56 with easy pedaling; each 1,000 feet of climbing at 10 mph on the throttle costs 136 to 161 Wh, and a full 330 lb load takes the flat figure to about 30.

Its best owner stands 5'0" to about 5'9", wants a low step to stop on, and needs a bike that folds into a trunk, a closet or an RV bay between rides.

On a 12-month Shop Pay plan from our listing, you pay $117.25 a month at 15% APR.

Settle two things before you pay: your inseam against the saddle table, and the path rules where you ride, since VTUVIA ships the SX20 as Class 2 at 20 mph on a 750 W rating. Tell us the route you ride most, and we will check its path rules before you order.

Source register

What each document behind this review supports.

T1 is the record itself, read from whoever issued it: a statute, the maker's own product pages, record, size chart and posts, and our own store record.

T2 is a party's own publication about its product or its measurements: the motor maker's workbook, research groups' and laboratories' published measurements, and a reviewer's recorded ride.

Expiry conditions

Re-read this page if VTUVIA changes the SX20's price, specification, motor rating, torque, range figures, speed, class note, weight, capacity, geometry, size chart, folded sizes or FAQ; if VTUVIA publishes a certification for the SX20; or if the price, the stock, the colorways, the parts prices or the Shop Pay terms change on our store.

Re-read it as well if a recall is published naming VTUVIA, if California amends §§ 312.5, 21204, 21212 or 21213, or if the BLM or the Forest Service changes its e-bike rules. Verified September 29, 2026.

References

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

1. VTUVIA, VTUVIA SX20 Antelope Step-Thru Folding Fat Tire Electric Bike 750 Watt — product page (highlight strip, feature blocks, Specs table, Geometry and Size guide, the notes under the table, FAQs, the size-guide image, as rendered for the US market). Retrieved September 28, 2026. https://vtuviaebike.com/products/sx20-foldable-step-through-electric-bike
2. VTUVIA, VTUVIA SX20 Folding Ebike — product record, variant price, compare-at price, availability, SKU, description and creation date. Retrieved September 28 and 29, 2026. https://vtuviaebike.com/products/sx20-foldable-step-through-electric-bike.json
3. VTUVIA, SX20 ANTELOPE Specifications (motor, battery, ranges, battery weight, recommended height, max load, bike weight, charger, charging time, tires, pedal assist, fork, derailleur, brakes). Retrieved September 28, 2026. https://vtuviaebike.com/pages/sx20-antelope-specifications
4. VTUVIA, SX20 Size Chart (rows A to L and the foldable size). Retrieved September 28, 2026. https://vtuviaebike.com/pages/sx20-size-chart
5. VTUVIA, VTUVIA Rear Rack (features: "For VTUVIA E-bikes (New SN100, New SJ26, SX20, Reindeer, and Gemini)", "Load capacity: 25 kg (55 lbs)"). Retrieved September 28, 2026. https://vtuviaebike.com/products/rear-rack
6. VTUVIA, VTUVIA SX20 Vs VTUVIA SF20: Easier Than Ever To Get On (March 16, 2023). Retrieved September 28, 2026. https://vtuviaebike.com/blogs/news/vtuvia-sx20-vs-vtuvia-sf20-easier-than-ever-to-get-on
7. VTUVIA, How to Folding SX20/SF20H to Easily Carry and Store (August 20, 2024). Retrieved September 29, 2026. https://vtuviaebike.com/blogs/news/how-to-folding-sx20-sf20h-to-easily-carry-and-store-1
8. VTUVIA, VTUVIA SF20H VS SX20 E-bikes: Which One Is Better For You? (October 30, 2024), "Rider Height and Accessibility" and the foldable sizes. Retrieved September 29, 2026. https://vtuviaebike.com/blogs/news/vtuvia-sf20h-vs-sx20-e-bikes-which-one-is-better-for-you
9. VTUVIA, Finding the Perfect Fit: How the VTUVIA Antelope SX20 Solved the "Short Inseam" Challenge for CJ, Rider Story (November 25, 2025 as printed). Retrieved September 29, 2026. https://vtuviaebike.com/blogs/rider-story/after-a-long-search-cj-finally-hits-the-trail
10. VTUVIA, VTUVIA SF20H — product page (specification table: certification line). Retrieved September 28, 2026. https://vtuviaebike.com/products/sf20h-fat-tire-folding-electric-bike-ul-certified-ebike
11. US Government Publishing Office, 15 U.S.C. § 2085 — Low-speed electric bicycles, subsection (b). Retrieved September 28, 2026. https://www.govinfo.gov/content/pkg/USCODE-2024-title15/html/USCODE-2024-title15-chap47-sec2085.htm
12. California Legislative Information, California Vehicle Code § 312.5, subdivisions (a) and (a)(2). Retrieved September 28, 2026. https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=VEH&sectionNum=312.5.
13. California Legislative Information, California Vehicle Code § 21204, subdivision (b). Retrieved September 28, 2026. https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=VEH&sectionNum=21204.
14. California Legislative Information, California Vehicle Code § 21212, subdivision (a). Retrieved September 28, 2026. https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=VEH&sectionNum=21212.
15. California Legislative Information, California Vehicle Code § 21213, subdivision (a). Retrieved September 28, 2026. https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=VEH&sectionNum=21213.
16. US Consumer Product Safety Commission, Recall data, title, product-name and manufacturer queries for VTUVIA, Vtuvia and vtuviaebike, a full-field read of a 623-record corpus including the names SX20 and Antelope, and controls Ancheer / Specialized / Trek. Retrieved September 28, 2026. https://www.saferproducts.gov/; the title query for VTUVIA, re-read September 29, 2026 beside its Specialized control: https://www.saferproducts.gov/RestWebServices/Recall?format=json&RecallTitle=VTUVIA
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