I'm brand new to cycling and I have an entry level Cannondale catalyst 3. I was riding my bike on a trail and when I got home I noticed my right pedal was wobbling around. I tightened it but the pedal still wobbles around. I'm thinking the crank arm thread is stripped but I don't know. the crankset and the pedals are all default that came on the bike when I bought it. I'm on a low budget so is there any way I can fix this or do I have to get a new crank set? PLEASE HELP
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Do you mean the pedal axle wobbles in the crank arm, or the whole crank arm wobbles on the bottom bracket axle?– Argenti ApparatusApr 15, 2019 at 17:27
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the pedal wobbles in the arm– Nathan PlumsteadApr 15, 2019 at 17:41
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Who assembled the bike? Getting the left and right pedals swapped in a common mistake, when assembled by a novice.– Daniel R HicksApr 16, 2019 at 2:24
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2 Answers
the pedal wobbles in the arm
That sounds like a stripped pedal thread. If the cranks are inexpensive or dubious, replacing them could be cheapest.
But in some cases a good bike mechanic can repair a stripped pedal thread by installing a helicoil or similar coiled insert - basically they tap out the hole for a yet larger size, and the wire insert fills up the space between that and the threaded pedal axle. You and your mechanic would have to make your own decision if this is appropriate in the circumstances of your particular case.
Normally modern pedal threads are specific to each side of the bike (the left pedal gets a reverse or left-hand thread) such that they will self tighten from precession when riding, especially on something with a freewheel where you cannot exert real reverse torque anyway. A pedal with the wrong thread for the riding torque of the side on which it is used will indeed unscrew, but being able to create that situation with modern components would be fairly unique to an exceptional case such as riding a fixed gear artistic cycling bike more backwards than forwards, or mistakenly installing a unicycle's wheel backwards in the frame. Otherwise, for the pedal to unscrew you'd have to have a pedal bearing so damaged that the bearing drag dominates over the precession.
An alternate possibility is that the pedal's internal bearings could be loose, such that the pedal's axle is fixed to the crank but the pedal itself is wobbling on the axle. That may be correctable by tightening if the bearing balls are not yet lost or can be replaced, or you may need a new pedal.
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+1 although I would say helicoils are a solution in most cases. It's rare to find a crank where too much material loss or distortion has occurred for it to be viable Apr 16, 2019 at 3:12
Assuming it's a square-taper bottom bracket (which is standard on the Catalyst 3) you probably have to replace the crank as the attachment surface is now distorted.
See Fixed gear cranks loosening and Square taper crankset develops play after changing bottom bracket for examples of what happens when you ride on loose square-taper cranks - you usually have to replace the crankset since it will never tighten properly again.
Given the standard crankset for your bike is a Prowheel 24-34-42, assuming you are in the continental US you can get the replacement yourself from a smiley large online retailer named after a big river in South America for all of about $25 with free shipping.
answered Apr 15, 2019 at 15:47
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Now if I were to replace the crank myself would I need any special tools cause I only have your everyday tools, I don't have tools specially designed for bikes Apr 15, 2019 at 16:01
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This answer assumed crank-BB axle issue but is equally valid for a crank- pedal axle problem. Apr 15, 2019 at 17:48
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You need a special crank puller to get the cranks off the square taper BB axle. Cranks are tightened onto the axle with a simple bolt, and pedals thread into the cranks. You really should tighten these to proper torque spec with a torque wrench - you have seen what happens when a pedal is loose. I’ve found I can ask my LBS to tighten bolts to spec after I’ve installed them for a nominally low fee. Apr 15, 2019 at 17:55
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@ArgentiApparatus - actually the crank-axle and crank-pedal interfaces are quite different. Pedal interface problems are more fixable; additionally pedals self tighten from use. Apr 15, 2019 at 20:24
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@ChrisStratton I mean replacing the crank is a valid solution in this case whichever interface is messed up. FYI: pedals don't self tighten. If you stop the pedal axle from rotating and rotate the crank forwards, the pedal axle unscrews from the crank Apr 15, 2019 at 20:59