Some progress on the conversion.

Pedal Sensor

I’ve made a new pedal sensor rotor and sensor mount. I wanted a bigger rotor so that the sensor could be positioned outside of the radius of the tandem eccentric bottom bracket. Not knowing exactly how the sensor worked I kept the same distance between magnets, so the rotor now has 16 magnets instead of 12. The rotor is made from Tufnol as I had some, it is non-magnetic and glues well.

The rotor bolts onto the drillings for the inner chainring. Most bikes will either have an inner chainring fitted or (for a tandem) a simple crank arm. The triplet tandem is probably unique here. I’m not sure if it makes any difference but I did make sure that the magnets are the same way round as the original rotor.

The bike is fantastic, however pulling a total of about 180kg up long hills leaves me worn out. It is ok until I hit bottom gear but at that point there is nowhere else to go other than leg power. We’ve always got up the hills – and I am definitely fitter and stronger than I was – but with my partner having an electric bike she has been suggesting routes that I don’t want to do due to the number of hills. I’d like to be able to ride further without worrying about the hills. I’m also curious about the kits and how they would work in practice.

So I did my research and bought a BPM kit from Woosh. Woosh have a great reputation and Andy’s patient answering of my innumerable queries has been outstanding. The BPM motor has a good reputation for lugging heavy bikes up steep hills where other motors simply melt – very important given that I’m expecting this motor to cope with pulling anything up to 250kg up 17% (1:6) hills. It is a front wheel motor; as mentioned before the rear wheel of the bike doesn’t have much weight on it and I get wheelspin on slippery surfaces with pedal power.

The kit arrived promptly and quality was good.