Kingbull Discover ST 2.0

Frame & fit

The ST in the name is the point of the bike. A step-through aluminium frame drops the top tube low enough that you swing a leg through rather than over — which matters far more on a 76.5 lb bike than it does on a 25 lb one. If you have ever tried to mount a loaded fat-tyre bike from the kerb, you already understand why this frame exists.

Fit is unusually broad for a single frame size: Kingbull quotes 5 ft 5 in to 6 ft 5 in, backed by a seatpost with 32.2 to 39.4 inches of saddle height and scale lines marked on the post so you can return to your setting after removing it. The head tube is tapered, cable routing is internal and guided, and the whole thing is 77 inches long — long enough that it will not fit diagonally in most car boots.

• Payload is the headline. 400 lb total capacity with 150 lb permitted on the rear rack puts real cargo, or a heavier rider plus a week of shopping, inside spec.
• Assembly is 85% done out of the box — front wheel, bars, pedals and fenders are the usual remaining jobs.
• Adjustable kickstand in aluminium, which sounds trivial until you park a 76 lb bike on soft ground.

Motor & torque

The motor is a customized Bafang 750W brushless rear hub rated at 80Nm. Bafang is a known quantity — parts, controllers and service information exist for it, which is not true of the unbranded hubs that fill this price bracket. 80Nm is the number that matters on a fat-tyre bike: heavy wheels and wide, high-friction tyres need torque to get moving, and the Discover has enough to launch a loaded bike uphill from a dead stop.

More important than the wattage is what controls it. This bike uses a torque sensor rather than the cheaper cadence sensor. A cadence sensor only knows whether the pedals are turning, so assist arrives as a delayed shove and leaves just as abruptly. A torque sensor measures how hard you are pushing and scales the motor to match, which is why torque-sensed bikes feel like a strong rider is helping you and cadence-sensed bikes feel like a switch. At this price it is the most consequential item on the whole spec sheet.

• Five assist levels plus a twist throttle (FT158X), so it is a full Class 2 bike — throttle-only riding is available.
• Walk mode at 2.3–2.9 mph, which you will use more than you expect when manoeuvring in a garage.
• Top speed 20 mph. Class 2 in the US, and there is no advertised Class 3 unlock.

Battery & range

48V, 15Ah, 720Wh, built on Samsung INR21700-50G cells, integrated into the down tube and removable for charging indoors. Naming the cell is meaningful — most bikes in this bracket say “lithium” and stop there. The pack carries UL 2271 certification, the cells carry UL 2580, and the complete bike carries UL 2849. That last one is the certification that covers the entire electrical system including charger and controller, and it is increasingly the line that decides whether a building will let you store the bike inside.

The 60-mile range claim should be read the way every manufacturer range claim should be read: lowest assist level, flat ground, light rider, mild weather, no wind, no cargo. On a 76.5 lb fat-tyre bike ridden the way people actually ride one — mid assist, some throttle, real hills — planning around 25 to 35 miles is more realistic. That is still a solid figure for a 720Wh pack; it is just not 60.

Brakes & safety

ZOOM HB-875-E hydraulic discs, two-piston, on 180mm rotors front and rear. Hydraulics rather than mechanicals is the right call and not a given at this price: a heavy bike carrying cargo at 20 mph asks a lot of a brake, and cable discs fade and need constant adjustment under that load. Two pistons on 180mm is a sensible match — not overbuilt, but not underspecified either.

Supporting details are handled properly. Brake levers include a motor cutoff sensor so the assist stops the instant you pull, the levers themselves are power-off type, and the lighting is 48V front and rear with a brake highlight on the tail light and IPX6 water resistance. A horn is integrated into the headlight unit.

• UL 2849 — complete e-bike electrical system
• UL 2271 — battery pack
• UL 2580 — battery cells

Tyres & suspension

26 × 4.0 in CST C-1752 all-terrain tyres with puncture-resistant construction, on 36-spoke aluminium rims. On a bike like this the tyres are the primary suspension — run them soft and they absorb far more than the fork does. That is what makes the bike work on packed sand, gravel, forest track and snow, and it is also why the ride is comfortable on broken tarmac despite the modest fork.

The fork itself is a Kingbull OS-D26 coil spring unit with 80mm of travel, adjustable preload and a lockout. Coil rather than air, and 80mm rather than 100mm or more, places it firmly in the “takes the edge off” category rather than the “handles real trail” one. Lock it out on tarmac to stop the bike bobbing under throttle, open it up on gravel. There is no rear suspension, so on sustained rough ground the saddle is where you will feel it.

Drivetrain

Here is the compromise. The gearing is Shimano seven-speed at the entry tier: an SL-M315-7R shifter, an RD-M310 rear derailleur and, critically, an MF-TZ500 freewheel with a 14–28T spread, driven by a 48T chainring. The chain is a KMC Z7RB.

Three things follow from that. First, a freewheel rather than a cassette means the axle bearing sits further inboard, which is a weaker arrangement under the loads a 750W motor and a heavy bike generate. Second, a 14–28T range with a 48T chainring gives you a tall, narrow spread — fine while the motor is helping, unpleasant if the battery dies and you have to pedal a 76 lb bike home. Third, the RD-M310 is the cheapest derailleur Shimano sells, and it shifts like it.

In practice most riders on a Class 2 fat-tyre bike spend their time in two or three gears and let the motor do the rest, which is precisely why a manufacturer chooses to save money here rather than on the brakes or the pack. It is a defensible decision. It is still the weakest part of the bike.

The price question — check the bundle maths

Kingbull lists the Discover ST 2.0 two ways, and the arithmetic is worth doing before you click buy. Prices below were read from Kingbull’s own listings on 24 August 2026.

Judged on the single-bike price, the value case is strong. A named Bafang motor with a torque sensor, a 720Wh Samsung-cell pack, hydraulic discs and full UL 2849 certification for under a thousand dollars is a genuinely competitive package, and the cheap drivetrain is the visible reason it can be that price.