Bicycle Mechanics - Cog wear

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Sailguy
11-22-02, 10:49 AM
After doing more reading on bicycle maintenence, I have learned that typically a chain will only last 1500-2000 miles or so. I know that I have put about 2500 miles on my chain, and I bought the bike used, so I am not sure how many miles were on it beforehand.

In reading that a streched chain can cause cog wear, I am curious what things I need to look for to determine if I need to replace my casette. I am going to buy a new chain this weekend so I can track actual miles on it and keep on the safe side. But I have not seen or read any good descriptions of how to tell if/when the cog wear warrants replacement.

P. B. Walker
11-22-02, 11:09 AM
From what I've heard you want to look for a couple of things. This is just what I've read and heard. So don't take it as the gospel.

- If the teeth are ground down to sharp points then it's time to replace.

- If you see teeth missing or cut off at the base, then it's time to replace.

- If you clean it really well and check for cracks in each of the cogs.

- If you see teeth that are twisted or warped. Teeth should be flat, like the tip of a regular screwdriver. Sometimes you'll see slightly twisted tips on the teeth. That's bad.


That's my two cents... hope it helps.

PBW
Rotifer
11-22-02, 11:50 AM
If you end up sprawled on the pavement when sprinting away from a stoplight - time to replace your cassette or rings.

pokey
11-22-02, 11:52 AM
Originally posted by Sailguy
After doing more reading on bicycle maintenence, I have learned that typically a chain will only last 1500-2000 miles or so. I know that I have put about 2500 miles on my chain, and I bought the bike used, so I am not sure how many miles were on it beforehand.

In reading that a streched chain can cause cog wear, I am curious what things I need to look for to determine if I need to replace my casette. I am going to buy a new chain this weekend so I can track actual miles on it and keep on the safe side. But I have not seen or read any good descriptions of how to tell if/when the cog wear warrants replacement. That mileage figure is stinky applesauce.If a new chain skips teeth on an old cassette,the cassette or at least the cog where the teeth are being skipped is worn out. If things are working ok now,It's ok.Learn to measure a chain so you don't throw money away.A foot of chain measures exactly 12" when a used chain measures 12 1/16" C-C of pins it's time to replace it.
pokey
11-22-02, 11:54 AM
Originally posted by P. B. Walker
From what I've heard you want to look for a couple of things. This is just what I've read and heard. So don't take it as the gospel.

-

- If you see teeth missing or cut off at the base, then it's time to replace.



- If you see teeth that are twisted or warped.


That's my two cents... hope it helps.

PBW Teeth on uniglide cogs look like this when brand new. Easy test.If chains skips cogs it's trash.