Bafang BBSHD/BBS02 Mid Drive Installation with PressFit Bottom Brackets

Installing Bafang Mid-Drive Motors on Press-Fit Bottom Brackets

Abbas from Golden Motor explains how to install Bafang mid-drive motors, such as the BBSHD and BBS02, on bikes with different types of press-fit bottom brackets.

The Bafang BBSHD and BBS02 are compatible with several bottom bracket types:

Threaded bottom brackets with an inner diameter of 33.5 mm

Press-fit 41 mm bottom brackets (PF41)

Press-fit 30 mm bottom brackets (PF30)

Press-Fit 41 mm Bottom Bracket Installation

A common issue with PF41 bottom brackets is that a standard BBSHD or BBS02 motor shaft, designed for 33.5 mm inner diameter, will not fit snugly in the 41 mm shell. The solution is to use adapter cups on both sides of the bottom bracket shell. The specific adapters needed depend on the width of your bottom bracket shell.

For typical widths of 68 mm, or for fat bikes with widths between 100 mm and 120 mm, use the PF41 adapter cups made by Lekki. These cups are pressed into the frame on both the drive and non-drive sides. After installation, secure the motor shaft using either the Lekki one-nut system or the stock interlock and outer lock rings.

For fat bikes, additional bottom bracket spacers may be necessary to ensure proper spacing of the motor within the wider shell.

Press-Fit 41 mm Bottom Bracket with 86 or 92 mm Widths

If your PF41 bottom bracket shell width is 86 or 92 mm, you have two options:

1. Use the Bafang 100 mm Fat Bike kit, which includes a longer motor shaft to fit these wider shells. Install the PF41 adapter cups and adjust the number of spacers to fit your specific shell width.

2. Use the 68 mm Bafang kit together with a specialized adapter made by Lekki for 86 or 92 mm shells. In this setup, the drive side (right side) uses a press-fit cup, and the non-drive side uses an adapter that bolts into place. For 92 mm shells, a 6 mm spacer is used to properly space the assembly.

The adapter is tightened with a Lekki socket or a Bafang installation tool, locking securely into the threads on the motor shaft.

Because this setup shortens the usable axle length, an axle extender included with the adapter kit is installed on top of the motor axle, extending it for proper clearance. This adapter solution is designed specifically for 68 mm Bafang kits on PF41 press-fit shells with 86 or 92 mm widths.

Press-Fit 30 mm Bottom Bracket (PF30)

Bafang mid-drive kits also support PF30 bottom brackets, which have a 46 mm inner diameter. Lekki offers an adapter kit for PF30 shells that works with the 68 mm BBSHD or BBS02 kits.

This adapter is straightforward to install and allows compatibility of Bafang mid-drive motors with press-fit 30 mm bottom brackets.

Summary

Measure your bottom bracket width and inner diameter carefully to determine compatibility.

Use PF41 adapter cups for standard 68 mm or fat bike widths on 41 mm shells.

For wider 86 or 92 mm PF41 shells, either use the 100 mm Fat Bike kit or a 68 mm kit with the Lekki adapter and axle extender.

PF30 (46 mm inner diameter) also requires a specific adapter to fit Bafang kits.