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Thumping in my crank armI have a brand new P-38. Less than 200 road miles. My last ride I noticed a thumping in my left pedal. I got off to examine and the left crank arm had about 1/64" wobble in it. I did not have an allen wrench big enough to tighten it. I continued riding. 10 miles later the the crank arm came off while in mid stride. I managed to stop safely and reattach the arm and tighten the nut by hand. A few mile later I purchased an allen wrench at a hardware store and tightened securely. Made it home OK. But I still have the thumping in the pedal. I changed the pedal last night and it is still there. Any suggestions? The dealer is a 5 hour drive away so thats not really and option. Thanks,
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thumping pedal
I took the bike to the LBS. He put a BIG allen wrench on the crank and gave it a good 1/2 to 3/4 turn. He said take it for spin and let me know how it feels. I rode it around the parking lot for about 1/2 mile and its was perfect. No charge. I'm back in the saddle.
Bill
I had a very similar thing
I had a very similar thing with my new-to-me P-38. After changing pedals and tightening chainring bolts all to no avail, it turned out that my bottom bracket was not tightened properly. Check that out.
thumping
Bill W
Excuse my mechanical ignorance, but how do I do that? Is there a special tool?
thumping sound on non-drive side of crankset
If you switched pedals, and still have the sound, then the pedal does not seem to be the problem. I think Blueridge is probably right. To tighten down the bottom bracket properly, you need a special tool that fits into the inner grooves. Any ordinary bike shop will have this tool, and will be happy to help you out. It should only take a few minutes, and should not cost much.
If you purchase the special tool, remember that the drive side cup of the bottom bracket tightens counter-clockwise, while the non-drive side tightens clockwise. Not knowing this little detail can get you into trouble.
Good luck de-thumpifying your new ride. It seems like the bike shop that prepared your Lightning did not do a very thorough job getting everything nice and tight.
Safe riding,
Joel
Bill Walsh
Bill W
I e-mailed the bike shop and they replied late last night. He agreed it probably is the bottom bracket. He strongly advised DO NOT RIDE and asked me to take it to a local bike shop to be tightened to torque. He said he would take care of the cost with the shop. Not too bad considering I wasn't hurt, it gets fixed quick, and I don't have to spend 8 hours driving back and forth to the dealer.
Bill
Joel responded with exactly
Joel responded with exactly what I would have said. Please let us know if in fact it is the bottom bracket. That's a great response from your bike shop too!