221b

Newbie: Chain and Cassette Replacement
A couple years ago I bought the 2005 Original Discovery Channel Trek Team Bike (1 of 100 made apparently) on the recommendation of a friend who's brother rides professionally.

I've had it tuned a couple of times, but as a noob I have little knowledge in bike maintenance save for chaining tires, lubing chain, etc.

I've ridden the bike about 750 miles in the two years I've had it and recently took a bike maintenance class where we learned to measure the chain. The mechanic told me that mine needed replacing and that I should also replace the back cassette too.

The chain has never slipped on me.

Do I absolutely need to replace the cassette as well? How can I determine if I need to replace the cassette as well? How much is it going to run me? I would like to keep decent part on it, but don't want to spend a fortune (the mechanic mentioned that if I put anything better than "105s" on it I would probably be wasting my money)?

Also, despite taking it in for tune ups, I know little about what else the bike has had replace. Seeing as it's going on 5 years now, what should I look for?

Thanks guys!

Matt in NYC

big chainring 

Its a 5 yrs old bike with 750 miles on it? I'd call that not even broken in yet. Replace the chain in another 3000 miles.

My bike is 45 yrs. old. Some of the parts are original. The chain and freewhweel have many thousands of miles on them. Bike parts dont wear out much. Just keep riding.

Velo Vol 

When you actually replace the chain (and I can't imagine it needs changed with 750 miles on it), see if the chain skips on the cassette. If it does, it's time to replace it.

banerjek

Even if you ride it in harsh conditions, 750 miles is nothing. Presuming there's not something totally insane you're neglecting to mention, both the chain and cassette should be fine.

sqharaway

The reason the mechanic told you to replace the chain and the cassette is because if you overuse a chain, the cassette tends to ware with it. Thus, if you change only the chain, often times your shifting will be off as the cassette does not line up with the new chain.

I agree with the others that this probably has yet to happen in a mere 750 miles, with a caveat. You said you bought the 2005 bike a couple of years ago. If the previous owner rode the bike much, your chain and cassette may well be more worn than you suggest.

storckm

Measure the chain with a tape measure or ruler. Center the 0" mark in the middle of the pin holding two links together. Look at the 12" mark. If the nearest pin is 1/16" away from the 12" mark, then replace the chain. Take a look at https://www.sheldonbrown.com/chains.html.
Mike

banerjek

Or if it wasn't lubricated.

Other than that, it would be hard to wear a chain out that fast. The measuring method storck recommends will work fine for determining if it needs replacement.

Seattle Forrest

That happened to me with a used-bike I had bought.

To the OP, a new cassette will run you about $35 if you're using 105s. It's not really a huge deal, but it's also kind of premature. Like others said, you should get about twice as many miles out of a chain as you have on the bike now. Unless you've never lubed it, and always started moving in too high a gear ... this is a little unusual.

longbeachgary

You should look for somebody who's going to ride that bike or better yet get your behind on that thing and ride it.

221b

Sorry, guys! It's kind of implied in my original post, but I bought the bike USED in 2008 from the original owner. He had it for at least three years and likely road it well over the 750 miles I put on it (minimum).

Thanks for all the help again!

kbtommy

Ah. Well, that changes things. Altogether possible it does need replacing. Also, if you're cross shifting a lot, that's not going to help things either.