Every conversion kit review on this site leans on two sources: what the listing claims and what owners report back. The QUEWATSA 48V 1000W 20 inch rear hub kit cuts that second source off entirely, because not one person has rated it. The detail page prints no star figure, the reviews page returns nothing, and the sales rank sits at 1,560 in cycling electronics, deep in the long tail. Everything below is the listing checked against arithmetic, and the arithmetic is the only outside witness this kit has.
The old version of this article described the box as holding a motor, controller, throttle, sensor, levers, and display. I can't stand behind that list any more, and the sections below explain why the listing itself makes it hard to believe.
What 26.72 mph means on a 20-inch wheel
The bullet promises empty speeds up to 26.72 mph from a 440 rpm rated motor, and on a 20-inch wheel those two numbers actually agree. A 20-inch wheel with a road tire turns over about 1.6 meters per revolution, so 440 rpm works out to roughly 700 meters a minute, which is about 42 km/h or 26 mph. The claimed 26.72 mph needs about 450 rpm. The two figures land within a rounding error of each other.
That agreement is the one place this listing's math holds together, and it deserves a plain caveat: empty speed means no load, no rider, no friction. It's a ceiling measured in a test bench fantasy, not a promise about what you will see on the road. Real riding with a person on the bike lands below it, and a headwind or a hill drops it further. When a kit advertises a speed, check whether it says no-load, because this one hides the qualifier in the odd phrase empty speeds.
There's also a copy smell here. The exact figure 26.72 mph appears word for word in other kit listings we have scraped, including one 750-watt kit from a different brand, which suggests the number travels between listings as template text rather than being measured per product. The rpm agreement still holds on this wheel, so the figure is plausible here, but plausible and verified aren't the same thing.
The complete-set claim against the parts row
Bullet one says the kit contains the complete range of accessories you need, so you don't have to buy anything separately. The spec table answers with a parts row that reads, in full, motor rear wheel kit. No charger is named, no controller is named, and no battery appears anywhere, which is normal at this price because no kit in this class ships one. You'll need a 48V pack, and our battery table sorts the field by cost per watt-hour so you can see what the second purchase really runs.
The word complete is doing a lot of work in that bullet, and the parts row refuses to carry it. 
I'd read the claim as marketing optimism rather than a box list, and I'd confirm the full contents with the seller before ordering, because a kit that arrives without its controller is a week of waiting away from a rideable bike.
Throttle or PAS: the listing picks both
The design bullet says the pedal assist sensor senses your rhythm and lets you ride without a throttle response. Three bullets later, the operation bullet says you control the speed through the thumb throttle, with battery indicator lights on it. Both control schemes appear, the listing never says how they combine, and no owner exists to settle which one actually works.
The display question belongs in the same bucket. The title promises a multifunction display, typo included, but no bullet describes a screen showing speed or mileage, and the only instrumentation mentioned is those indicator lights. Our data row records the display as not included, which agrees with the bullets against the title. If the display matters to your build, this listing won't promise it in writing anywhere except the title string.
What the price buys per watt
At 139.99 the kit works out to about 0.14 per watt, which ranks 54th of the 182 kits we track by that measure. Eighteen of the 71 tracked 1000-watt kits do better per watt, so the pricing is middling rather than sharp. By raw price it sits 37th of 191, and the current listing prices it the same as our row does.
The 1000 watts on 48 volts implies about 21 amps of continuous draw from whatever battery you pair with it, and the torque figure of 40 newton-meters turns into roughly 160 newtons of push at the ground on a 20-inch wheel. Those are reasonable numbers for a small-wheel build, the kind of bike folders and BMX frames give you. The motor being gearless means no brushes to wear out, and Wikipedia's hub motor article, rechecked for this rewrite, notes the trade: direct-drive hubs run heavier and drag more when you pedal unpowered.
The load claim gets its own eyebrow: 308.64 pounds is 140 kilograms exactly, a precision that comes from converting a round metric figure and calling it a spec. The number is plausible, but it's a unit conversion wearing a decimal point.
One year of warranty against zero data
The listing's warranty row says 1 year, which is a real, written promise and one of the few rows in the spec table with actual content in it. Against it sits a record with no ratings, no texts, and no histogram. Nobody in the public record has owned this kit long enough to say whether the warranty gets honored, whether the motor holds up, or whether the claimed 82 percent efficiency is real.
That's not an accusation. It's the honest state of the evidence, and it's why this article talks about arithmetic instead of experience. The closest comparisons we have rebuilt are the Mahugde 48V 1000W hub kit, where 16 ratings and a handful of real owner texts turned a cheap listing into a measured gamble, and the LOYALHEARTDY 20-inch kit, where a single owner text carried the whole record. QUEWATSA sits below both on evidence, at zero.
Frequently Asked Questions
Does the QUEWATSA kit include a battery?
No. The bullets never claim one, the parts row names only the motor rear wheel kit, and no kit in this price class ships a battery. Budget for a 48V pack and check the battery comparison table for cost per watt-hour.
Is 26.72 mph the speed I will ride?
No. That figure is the no-load ceiling, and the listing's own 440 rpm rating works out to the same speed on a 20-inch wheel. A rider, friction, and hills pull the real number below it.
Is this kit a good deal?
About middling. It ranks 54th of 182 kits we track by cost per watt, with 18 of the 71 tracked 1000-watt kits priced better per watt. The price is fair, not sharp.
Should I buy a kit with zero reviews?
That depends on your appetite for risk. Everything here is untested by owners, the brand name and the manufacturer name don't match, and the title carries a typo. If you buy one, keep the return window in mind and test every component the week it arrives.