PERTH ELECTRIC BICYCLES

Bafang mid-drive motor on carbon fibre bike.

Bafang mid drive carbon fibre bike

This was a very nice flat bar carbon fibre road bike that came into our shop with a customer asking us options for it to be electrified. Complete carbon fibre bikes represent one of the few difficult categories of bikes to retrofit an electric bike conversion kit to. The problem lies in that using a hub motor is too powerful for either the front or rear axle dropouts to handle and the chance of snapping the bike forks or the rear axle dropouts is too high to risk. General rule of thumb is never to install a hub motor onto anything carbon fibre; they are just not made to withstand the rotational forces of the electric motor axle. Mid-drive kits in our experience have never been able to be installed due to the gap being too small on the motor between the shaft that goes through the bottom bracket shell and the motor itself. Usually carbon fibre bikes are built up around this area compared to steel or aluminium framed bikes. On this particular bike, it was quite a minimal gap so we tried a few different motors to see if one could be installed. Both the Tongsheng and Lingbei torque-sensing motors could not fit, just 1mm off but even 1mm was too much. However, the Bafang mid-drive kit (BBS02 we used) just fit with a bee’s Johnson clearance. Thus, this became the first fully carbon fibre bike that we converted to be electric. Enough said…