- Just sharing with the forum how I fitted a 12-magnet drive side PAS sensor to a Campagnolo Power Torque bottom bracket on a road bike which uses external bearing cups. I chose this type of PAS sensor for its aesthetics as it is very discrete. This idea is also suitable for Shimano Hollowtech 2 bearing cups.
- The need for something non-standard arose as the magnet ring is designed to attach to a 22 tooth chainring which is found on MTB chainsets, but the road bike had a 50/34 chainset, thus on its own the PAS sensor as supplied wouldn’t fit.
- With the aid of a 3D printer, a suitable flange was made which is best described as similar to a top hat. The hat brim is of a size to fit the 34 tooth chainring without fouling the chain and recessed into it is the crown whose diameter is made to hold the magnet ring.
- The depth of the crown is such as to leave the magnetic ring suitably distanced from the hall sensor (the latter is held in place by the bearing cup, see pic below) and requires a centre hole to allow the cup bearing to protrude through.
- Notches need to be designed in to the ‘hat brim’ which for a 5 bolt chainset is at every 72 degrees. The brim being flat is simply glued to the chainring as is the magnet ring to the ‘hat crown’.
- Hopefully the pics below help to understand my ramblings and I’m happy of course to take any questions.
