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Old 07-09-12, 02:39 PM   #1
David Bierbaum
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Chainring wear. Is it time for me to replace all this?

I just noticed today, while cleaning gunk out of the cassette and chainring, that my chainring seems to be displaying the classic look of the worn chain and/or chainring. Excuse the blurry photo. I'm not used to my new camera just yet.


My cassette doesn't look so bad, but I spend most of my biking life in that middle chainring. About how bad can one of these get, before one needs to change?
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Old 07-09-12, 02:50 PM   #2
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Depends on what you define as needs to change. Grinding when pedaling, even on a clean chain and especially on a new one is a pretty good indicator, may not shift as well, and the teeth usually become pointed. It will "work" pretty much indefinitely, but will be much more pleasant when you replace it.

One usually checks at the front of the chainwheel rather than the bottom.
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Old 07-09-12, 04:01 PM   #3
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How long has it been since Shimano stopped making Ultraglide chains? Probably time to replace it!
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Old 07-09-12, 04:45 PM   #4
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shimano still makes UG chains . some new low end bikes in the shop still use them .
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Old 07-09-12, 06:34 PM   #5
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It would be much easier for folks here to discern tooth wear if the photo shows just the teeth in profile.

Severe wear can result in slippage under maximum load, which is dangerous.

Likely the chain is somewhat worn, and should be precisely measured pin-to-pin over a 12" length.
Anything over 1/16" per foot (0.5%) is considered worn out by today's standards, and I concur.
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Old 07-09-12, 08:55 PM   #6
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How many cassettes have you gone through? A set of chain rings should last through several cassettes unless you let the chains become severely worn. I suggest that you measure the chain as suggested above and replace it if it is worn. Cassettes and chanrings should be replaced on condition not by inspection; if they do not skip with the new chain all is good.
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Old 07-09-12, 09:26 PM   #7
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You can ride a chainring until it's pretty badly worn with little or no problems. If the chain is running OK, and doesn't slip under power then you're still OK. I check for chainring ear as follows. Use a small screwdriver to lift the chain away from the chainring at the front (half way around the wrap). If you can see 1/4" of daylight under the chain the ring is pretty worn, but I have one ring where I can pull the chain almost 1/2" off and it still doesn't slip, (but it does creak under load).
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Old 07-09-12, 10:37 PM   #8
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The trekking bar and the rack on my bike are the only new parts. All the components are original to the bike when I bought it new... in 1992.

I've already blown my budget for this year, so unless things get noticeable, I'll just leave things be for now. There seem to be two camps with regard to change. The change chain, and you should change the sprockets camp, and the change the chain, but leave the rest unless there are problems camp.

Edit: I measured my chain, and it has no wear at all! 12 inches, 12 links, perfect match, relaxed or under tension. The wear is all in the ring, it seems.

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Old 07-10-12, 04:33 PM   #9
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Enjoy your new bike!
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