Cicony 104BCD Chainring Spider Adapter

Small rings change how a BBSHD behaves on a hill. At the same road speed, a 32T ring makes the motor turn faster than a 46T would, and a motor that spins faster draws less current for the same push. Less current means less heat in the windings and the controller, which is what keeps power flowing up a long climb instead of fading halfway.

The Cicony adapter is a CNC-machined aluminium piece with an anti-corrosion finish. On its outer face it presents four bolt holes on a 104 mm circle. Any four-hole ring from 32T up to 55T fits that face, which covers everything from steep-trail climbing rings to fast commuting rings.

At 90 rpm on an 11T cog with a 2.1 m wheel, the top-end speed of each common ring looks like this.

The low gears move down in step. On a 51T climbing cog, the 32T ring crawls at about 4.4 mph at the same cadence, which is the gear you want pulling a loaded trailer up a fire road.

The adapter mounts with M5 screws rather than being described as a spline fit, which suggests it bolts to the drive's existing fixing points. Even so, verify before you commit. Hold the old ring next to the adapter's photos, count the fixing holes and check their spacing against what your motor presents once the ring is off.

1. Remove the crank arm and stock ring, and note how the ring was fixed.
2. Count the screw holes on the motor's output and measure their spacing.
3. Compare with the adapter's hole count and pattern before fitting anything.
4. Bolts that need force to find their holes mean the wrong part: stop, and do not drill or file.

Motor identity is easy to confirm. The BBSHD is the larger 1000W unit, also sold as the BBS03; the BBS01 and BBS02 are the smaller 250W–750W units. The BBS02 vs BBSHD comparison lists the physical differences.

If your motor turns out to need a dedicated adapter, the answer is usually a BBSHD-specific ring. Direct-mount rings such as mGYDY's 12 mm offset ring or ebsenopower's 8 mm offset ring skip the adapter altogether.

Lay out the tools first. You need a crank puller that matches your crank arms, the hex key for the crank bolt, hex keys for the M5 screws and ring bolts, a small torque wrench, medium-strength threadlocker and a chain tool. Crank removal, puller and all, runs step by step in the BBSHD install guide.

1. Pull the drive-side crank arm and remove the stock ring.
2. Clean the mounting faces so no grit sits between metal parts.
3. Fit the adapter with a dab of threadlocker on each M5 × 16 screw and its washer.
4. Tighten in a star pattern, a little at a time, to the torque the ring maker gives.
5. Bolt the four-hole ring on, then refit the crank.

Small screws strip easily. Snug each one by hand before reaching for the torque wrench, and stop at the specified figure rather than going by feel. An over-tightened M5 screw that stretches will loosen later, which is worse than one set correctly the first time.

Chainline comes next. A flat adapter plus a flat ring sits in a different plane from the stock ring, so measure from the frame centre to the ring's teeth and compare with the middle cog. Many 104BCD rings are made with built-in offset, which lets you move the tooth plane in or out without spacers.

Finish by setting chain length. Going from a 46T stock ring to a 34T ring removes about three inner-plus-outer link pairs.

Cicony specifies four-hole positive-and-negative tooth rings, which is another name for narrow-wide. That profile holds the chain without a front derailleur, which matters on a mid-drive where a chain drop under power can jam the chain between ring and frame.

• 32T–34T: cargo bikes, steep trail builds and heavy riders on 48V.
• 36T–38T: fat bikes on soft ground, hilly commuting, towing.
• 40T–44T: mixed city and trail, the closest to all-round.
• 46T–55T: fast flat roads; beyond this, a 130BCD spider takes over.

Match the ring to the chain as well. A ring rated for 10–12 speed chains suits modern wide-range cassettes; rings for 6–11 speed chains fit older drivetrains and hub-gear builds.

Steel four-hole rings are worth a look for high-mileage cargo work. They weigh more than aluminium, but they wear far more slowly under a motor that pushes hard from a standstill at every junction.

Compared with a direct-mount ring, the adapter route adds a joint and a few grams, but it gives you flexibility. A rider who wants 34T for winter trail work and 44T for summer commuting can swap rings in minutes. The chainring and chainline guide compares both approaches.

For road gearing above 55T, the IQ Labs 130BCD spider covers the other end of the range.