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Why I ride there's a strange and intermittent 'knocking' from one side of the bike. I feel it through the LH pedal. It's like when you rounded a square taper bottom bracket. It isn't every revolution. I don't really know the cause.
I can't replicate it.
There doesn't feel to be any looseness in the bottom bracket, crank arm or pedal. XTR M970 crank. Cheaper Shimano BB and cheapish Wellgo flat pedals.
I don't have spares to narrow down or eliminate the knocking. Any suggestions as to the cause?
Thanks
Does it always happen at the same point in the pedal stroke?
Could be a couple of things, either the spline interface with the left crank is worn (never happened to me, but I've heard of it occurring) and there is developing play between the RH axle and LH crank arm. You won't replicate the forces transmitted through pedalling easily by hand.
Or it could simply be worn bearings/bushings in the actual pedal?
If the LH crank has been on and off a few times, it’s possible that a little material has been removed from the splines leading to the crank rocking on the axle.
I've had three reasons for this:
1, Knackered BB but with some odd notching
2, Knackered pedal
3, Rather randomly, a VERY slightly bent tooth or two on a chainring which visually weren't out of line but in certain combinations of gearing and effort would introduce an odd noise or occasionally chain drop.
BadlyWiredDog - no. I can't replicate it. Even when it's just happened then back-pedalling a few degrees and pedalling again can't reproduce it.
PMJ & SillyOldMan - wouldn't this mean consistency? It does feel like the old rounded square-taper issue but it isn't consistent.
atlaz - 1. maybe. 2. maybe. 3. - I hadn't thought of that. I'll check but I don't think it is. It's definitely from the LH side.
Is it your knee? 🙂
Worn cotter pin 😉