Coaster
09-21-02, 07:42 AM
How do I know when a Road bike chain should be replaced? Does the side to side flex indicate how much wear a chain has had?
Thanks,
Rich
Thanks,
Rich
Bicycle Mechanics - When to replace chain
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moabrider47
09-21-02, 08:57 AM
One way you can tell that the chain has had it is if it measures as though it is "stretched out" long-ways. Chains do not actually stretch, but instead, pieces of the chain develope some play, making it measure out longer than when it was new. By this, I mean that as a chain wears, the distance from roller to roller increases slightly. This can be measured with a tool from Park Tool. I believe it is called a Chain Checker.When this distance becoms too great, you may start to experience a skipping when the drivetrain is put under a heavy load. Assuming that you derrailleur is set up correctly, what is happening is that a roller sits on top of a tooth on a cog as it comes around the bottom of the cog, and then as it gets to the top of the cog, the heavy load forces the chain to fall between the teeth where it belongs, and you feel the pedals "jump" forward just slightly and then catch again. You can always prolong chain life by making sure that it is cleaned and lubed well also.
-Moab
EDIT: I forget to add that this minute length increase in the chain can cause some lateral sid-to-side flex, but the easiest way to measure chain wear is with the tool as mentioned above.
-Moab
EDIT: I forget to add that this minute length increase in the chain can cause some lateral sid-to-side flex, but the easiest way to measure chain wear is with the tool as mentioned above.
bikerTeen
09-21-02, 10:11 AM
Here's what I've heard/read:
12 links of a standard chain should measure exactly 12 inches. If they measure 12 1/8" or more, the chain has stretched and should be replaced.
You can easily measure this with a ruler: put the 0 mark on one of the joints of the chain, and then see where the 12 mark is. If the chain is good, the 12 mark should land right in the middle of another joint of the chain. (I know there's a better word than "joint," but I can't think of it... hmmm...)
12 links of a standard chain should measure exactly 12 inches. If they measure 12 1/8" or more, the chain has stretched and should be replaced.
You can easily measure this with a ruler: put the 0 mark on one of the joints of the chain, and then see where the 12 mark is. If the chain is good, the 12 mark should land right in the middle of another joint of the chain. (I know there's a better word than "joint," but I can't think of it... hmmm...)
Coaster
09-21-02, 10:56 AM
Pivot? Anyway, thanks for the replies. I'll check it.
Rich
Rich
Cipher
09-21-02, 11:07 AM
I think its called a link pin. ;)
John E
09-21-02, 01:44 PM
Originally posted by bikerTeen
12 links of a standard chain should measure exactly 12 inches. If they measure 12 1/8" or more, the chain has stretched and should be replaced.
I now adhere to Sheldon Brown's 12 1/16" standard, which is equivalent to 0.5 percent elongation. Incidentally, most of the elongation is due to wear at the pivot pins, rather than to stretching of the chain's side plates.
12 links of a standard chain should measure exactly 12 inches. If they measure 12 1/8" or more, the chain has stretched and should be replaced.
I now adhere to Sheldon Brown's 12 1/16" standard, which is equivalent to 0.5 percent elongation. Incidentally, most of the elongation is due to wear at the pivot pins, rather than to stretching of the chain's side plates.
pokey
09-21-02, 06:19 PM
John E and Sheldon are right about the 1/16" stretch.Waiting till 1/8" will also ruin the cassette.
roadbuzz
09-21-02, 07:20 PM
Originally posted by pokey
Waiting till 1/8" will also ruin the cassette.
... and chainrings. The damage can get pretty costly. Even if you keep your chain clean and lubed, a "stretched" chain is noisey. If you think your chain is making more noise than it should, take a minute and measure it.
Waiting till 1/8" will also ruin the cassette.
... and chainrings. The damage can get pretty costly. Even if you keep your chain clean and lubed, a "stretched" chain is noisey. If you think your chain is making more noise than it should, take a minute and measure it.