Originally Posted by
gosmsgo
I've started changing my chains every 2000 miles or so and at that point they hardly show any measurable "stretch" at all. In fact they are still within new chain specs according to my LBS.
I conjecture that a big variable in how much a chain stretches is riding style. My guess is that mashers tend to stretch chains and ruin cassettes much faster than spinners.
At 4200 miles on my new bike my cassette still looks pretty much brand new.
Even worn and badly damaged cassettes often look "pretty much brand new". The damage to the cassette is not something you see... it's something you feel when your chain skips.