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| | #1 |
| | Bent chainring or cranks? On Sunday I noticed my drivechain was making more noise than usual - almost a clicking at a particular point of each crank revolution. Got back home, took chain off and spun the cranks hard whilst holding the seat tube and there's no vibration or noise. So definitely not the bb. No side to side wobble of the spindle, either. It's (Miche) only a couple of months old, not done too many miles, anyway. Put it all back together, and with the bike upside down, when I spin the cranks you can see the chain move side to side as the cranks go round. Take off the chainring, lay it flat, with the outside facing up, on a couple of surfaces and one side is raised by about 1-2mm - you can press it up and down. Take it to Condor and they lay it facing down on a glass counter and say it's fine and to bring the cranks in. I've watched the cranks go round, and I don't think it's them. I put a bit of blue tack between the chain stays and inside of the spider, and it doesn't move much. Perhaps 0.5 mm? Next to nothing; probably 0.5mm because of me moving rather than the cranks relative to the frame. I was wondering what anyone else might think it is? I'm taking the cranks to condor tomorrow morning, but i don't see how they're going to test them - just wondered if any of you had any suggestions... takes me ages to get there on public transport plus I've got loads of uni work I'd rather be doing! Edit: they're condor miche cranks. |
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| | #7 | ||
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Hmm, I don't think it's that because I can see that the chain moves side to side as the cranks rotate. I'll guess I'll find out tomorrow when/if I put them back on. | ||
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| | #10 |
| | If the noise happens at a particular point of each crank revolution, then (unless you are running 1:1 gearing) the problem is with either your cranks, or bottom bracket. It is not your chain Sorry, I've just read the OP again. Your chainwheel is bent Last edited by fruitbat; 4th June 2008 at 00:23.. Reason: grandma and stupidity |
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| | #11 |
| | Try seeing if the chainring is bent vertically, or offset slightly in the spider bolts i.e. it moves slightly up and down rather than side to side like you've already ruled out. That would make your chain slightly tighter at a certain point in the pedal stroke, and cause such a noise, perhaps. If it's that, there is an excellent article in Sheldon's about it but i can't for the life of me find it right now. It's in the fixed section, somewhere :) Or alternatively it could be your cog on the rear with a similar problem. |
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| | #13 |
| | my reply "I've watched the cranks go round, and I don't think it's them. I put a bit of blue tack between the chain stays and inside of the spider, and it doesn't move much. Perhaps 0.5 mm? Next to nothing; probably 0.5mm because of me moving rather than the cranks relative to the frame." thats not even worth mentioning |
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| | #15 | ||||
| | Tried it - made no difference. Quote:
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I'm pretty sure it's not the cog. EAI on Goldtec, and the chain and cog move round smoothly there, it's between the cog and chainring that you see the chain move laterally. Quote:
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This is so strange :S Thanks to all your replies so far. | ||||
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| | #18 |
| | hey eeehhhh, this sounds eerily similar to a problem i've been having for ages. i hear and feel a sort of clicking at certain points but had no idea what it was for a long time. i thought i'd finally figured it out—my chainring is extremely close to the chainstays (wide enough to slip a spoke card in, maybe a bit wider), which wasn't a problem for the first six months or so, but when i looked closely at the chainring spinning slowly it seemed to be rubbing the stay slightly at certain points, hence the clicking. i checked again this morning, though, and could feel it clicking, but it was hard to tell if the chainring was actually touching the frame at those moments. after reading your post, i'll try spinning the cranks with the chain off in the morning and see if that's what it is. it's probably unlikely, but is there any chance this is what's happening with your chainring (ie, it's rubbing the stays at certain points)? what also struck me about your post is that there seems to be lateral movement in my chain, too, except it doesn't move side to side, just looks as though the chain is bent to the side and then bends back again. [sorry if this isn't clear, mechanics aren't my forte and i'm finding it hard to describe, let alone fix] i always thought it was the chain just being full of grit, or slightly bent, but it's a fairly new chain, so i don't know what's wrong. anyway, let us know if you figure out what is wrong and manage to fix it, i'm curious to know if we have a similar problem, and/or whether this is a common issue for fixed/singlespeeds. cheers. |
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| | #19 |
| | I reckon it's either that the lengths of the arms on your crank spider aren't all the same - so a manufacturing fault which shouldn't be likely on those miches - or it's your peddling* motion that is pushing the chain off line, maybe try tightening your cleats/straps? *that's as in turning the pedals not hawking goods ;-) |
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| | #23 |
| | Oops, I forgot to reply to this. Well I took the whole thing to Condor and two guys think it's normal. I'm not convinced, but I'm just going to put up with it :-/ I understand that all cranks have a degree of sideways movement, but I think with the Miche ones it's a bit too much. |
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