A black aluminium 42-tooth ring with its chain guard built in, made for Bafang's BBS02 and BBSHD mid-drives. The offset keeps the chain aligned with the motor, and the guard keeps trousers out of the teeth and the chain on the ring.
A BBSHD commuter spends a lot of time in street clothes. The stock BBSHD ring comes without a guard, so the chain sits exposed right where a trouser cuff swings past on every pedal stroke. The result is familiar: grease stripes on the right leg and, now and then, fabric caught in the teeth at a traffic light.
Powallon's 42T ring builds the guard into the part. A disc sits outboard of the teeth, covering the chain where it wraps the ring, so cuffs brush the guard instead of the chain. It also acts as a bash surface and an outer wall that helps stop the chain from jumping off the ring over curbs and potholes.
Many commuters try a trouser clip or roll their cuff instead. Those work, until the day you forget. A ring with a guard fixes the problem permanently and costs nothing in daily hassle.
Cut through gravel shortcuts and the guard's chain-keeping role is as valuable as the clean trousers. Guard, offset and narrow-wide profiles stand side by side in the BBSHD chainring guide.
| Spec | Value |
|---|---|
| Brand | Powallon |
| Model | bbs42t-cr |
| Motor fit | Bafang BBS02 and BBSHD mid-drives |
| Tooth count | 42T |
| Chain guard | Integrated, built into the ring |
| Offset | Engineered offset for mid-drive chain alignment |
| Material | Aluminium alloy |
| Colour | Black |
| Suited riding | City riding and moderate terrain |
| Guard role | Helps prevent chain drops, keeps clothing clear |
| Package size | 10 × 8 × 0.5 in |
| Included | Chainring with integrated guard |
| Warranty | 1 year |
Powallon describes 42 teeth as a ratio for city riding and moderate terrain, and the numbers back that up. A 42T ring on a typical commuter cassette covers a broad spread from easy hill-climbing gears to comfortable cruising speed, without the motor straining in the lowest gears or spinning out too early.
Take a 700c commuter wheel of about 2.1 m circumference and a relaxed 80 rpm cadence, and 42T gives these road speeds. Speeds are straight arithmetic from ratio, wheel size and cadence, before any motor help or slip.
| Rear cog | Ratio | Speed at 80 rpm | Where you use it |
|---|---|---|---|
| 11T | 3.82 | about 24 mph | Flat roads, tailwind, open bike lanes |
| 14T | 3.00 | about 19 mph | Steady city cruising |
| 21T | 2.00 | about 12.5 mph | Rolling hills, pulling away from lights |
| 34T | 1.24 | about 7.7 mph | Steep ramps and bridge climbs |
That spread suits a commuter who spends most of the ride between 15 and 24 mph and meets the odd steep bridge or hill. A 46T or larger ring would push every gear higher, which helps top speed but makes steep starts harder on the motor.
For hill-heavy routes, a smaller ring lets the motor spin faster and run cooler. Why motor revs matter for heat is spelled out in the BBSHD 1000W guide.
Powallon names both the BBS02 and the BBSHD for this ring. Those motors use different chainring mounts: a ring made for one will not bolt to the other. Treat the two motor names as two versions of the part and make sure the one you order matches the motor on your bike.
The motor code is printed on the housing. BBSHD motors are sometimes labelled BBS03 or carry Bafang's newer M615 or M625 codes, and all of those take the BBSHD ring. BBS02 and BBS02B motors need the BBS02 version.
The offset is designed to keep the chain aligned with the mid-drive. On a regular 68–73mm bottom bracket, an offset ring typically pulls the chain toward the middle of the cassette. On a fat bike with a 100mm or 120mm shell and a wide rear hub, that same offset may pull the chain too far in, so check before a long ride.
Torque for the crank and motor hardware is detailed in the BBSHD install guide.
Two other 42T-class rings for the BBSHD do without a guard. CHAOZHU's 42T has a deep 20.5mm offset and weighs 177 g. The Generic line includes a 42T aluminium offset-correction ring. Powallon's difference is the guard, and that makes it the commuter's pick among the three.
Pick the Powallon if you commute in normal clothes, ride city streets with curbs and potholes, and like the idea of one part that handles chain retention and clothing. Pick the CHAOZHU if chainline is your main problem on a trail bike and you want a light, bare ring with a stated offset figure. Pick a steel or smaller ring if cargo, towing or steep trails make up most of your riding.
Three checks come first: the motor code on your housing, the version you are choosing, and how your chain speed matches the ring. If you ride a fat bike, measure your chainline first, since a ring aimed at regular frames may sit too far inboard.
Weight is the one place the guard costs something. An extra disc of aluminium makes the ring heavier than a bare one of the same size, though on a bike carrying a BBSHD and a big battery the difference is hard to feel.
Keep the guard clean. Road grit collects between the guard and the teeth, and a quick brush-out during chain cleaning keeps it from grinding the chain.
Powallon makes it for both motors, but they use different mounts. Order the version that matches the model code on your motor housing.
It covers the chain where it wraps the ring, keeping trouser cuffs clear and helping stop the chain from jumping off over bumps.
For city riding with moderate hills, yes. It spreads gears from easy climbing to about 24 mph at 80 rpm in an 11T cog on a 700c wheel.
Check the chainline first. The offset suits regular frames; wide fat-bike hubs may need a ring with a shallower offset.