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What a difference a new chain makes !

Posted: Sat Feb 09, 2008 6:42 pm
by sandman
Well being a relative Roadie Newb, I managed to squeeze 3500km out of the bike chain because I didnt know any better :shock: . I bought the bike new in September 2007 and had no idea as to when to swap the chain.

Anyway, I put a dura-ace chain on the bike last week, pulled the rear cassette down and gave it a very good clean, my god does it run nice now. Its so quiet, the gear changes seem nicer however I'm waiting for my new Ultegra chainring and cassette to turn up this week and it should be even sweeter !!!

I also bought a spare chain so i think I'm going to pay a little more attention to the wear on the running gear and swap it before its totally stuffed :P

Ciao Pete

Posted: Sat Feb 09, 2008 7:36 pm
by Boognoss
Being a total road noob (give or take :-)), when should you consider changing the chain? Is there a general km limit, or when it's worn, is skipping gears, or what?

Posted: Sat Feb 09, 2008 7:39 pm
by sogood
3500km? Why are you planning to change the chainring and cassette?

Chain wear is specified by the amount of wear (stretch) rather than by mileage.

Posted: Sat Feb 09, 2008 8:35 pm
by Hawkeye
sogood wrote:3500km? Why are you planning to change the chainring and cassette?

Chain wear is specified by the amount of wear (stretch) rather than by mileage.
+1. If the new chain isn't skipping under max load, then there's no need to change cassettes. Chainrings last for ages. I've replaced the middle and top on my commuter only because with my mass and hte fact they were cheapo OEM units to start with, I was bending the teeth over and giving myself major shifting issues. The little one (usually the first to go) is still good though after some 6-7,000km.

As for when to retire chains, I use a Park Tools go/no go chain wear indicator. Worth every cent and then some.

Posted: Sat Feb 09, 2008 8:42 pm
by sogood
Should provide a bit more info.

As posted in another thread just yesterday, a quick way to check for wear is to measure b/n two rollers with a vernier caliper using Campagnolo's spec (equivalent of 0.5% wear). Those chainwear tools from Park works off a similar principle.
Image

Otherwise, the traditional method of measurement is to measure 12 links. Read the section on Measuring Chain Wear on the following page.
http://www.sheldonbrown.com/chains.html

BTW, the time to change is when any segment of a chain has exceeded the spec. The cassette has been commonly quoted to last the life of two sets of chains (timely replaced). Persisting use of a worn chain will just accelerate the demise of the cassette. Waiting for the chain to skip is a pretty late sign.