As I was riding downhill I got to thinking about adjustable cranks. I am sure many will feel a double-hole crank is enough, but with Cape Town’s different terrain, I disagree. Sometimes I ride offroad, then extreme hills, then flats and everything in between.
I swap between 127, 150 spirit cranks, 145 zero Q or 150 moment cranks as that is what I currently have, but it has left much to be desired.
I was originally inspired by the flip chip on the Columbus forks to change the rake/trail of the bike.
It is no art piece, but at least my 5-minute doodle catches onto the main concept. The aluminium crank would have a slot and teeth of sorts to hook the two-part chip (just what I call the top and bottom piece) onto. The chip is tightened by the back piece compressing against the front and the second bolt is for more clamping force. The teeth would allow 2-3 mm increments to be reached and additionally, if the chip is designed correctly depending on if the pedal hole is flipped to the top or the bottom it makes it so that 60% of the teeth could be used to achieve even smaller increments than the teeth jumps due to offset.
Q-Factor
With a second set of chips, you could also change the Q factor using the same crank without any compromise in strength as a washer on a pedal would have.
The ends would be rounded-ish allowing a snug fit and for it to be flipped so that the extra bolt is at the top or bottom allowing a good range.
This would have compromises on strength, so no 10-meter drops, but for distance or the majority of riding, I think this has the potential to be very useful to certain riders.
The actual engineers and experienced riders please chime in. There would of course be a million changes to make to the design, but with today’s CNC manufacturing setups, it is easier than ever to produce them without first creating specific tooling.
