Racing Bike Chainrings

[treborman]

I have a racing bike which is not that old ,but the bigger chainring of the two has got one or two teeth missing . the bike shop says if I change the chainring I need to change the chain and rear cassette to.
is the bike shop just after work or is this true?

[Answerprancer]

There is some truth in this - especially with the block as they wear together.
IMO you should go ahead and order the chainring. You'll know if there's a problem when you start honking (standing up and pedaling hard) if the chain is stretched and worn it will skip.

[Booldawg]

if you've teeth missing then it sounds like the drive-chain has certainly taken some punishment!

Its usually more of an issue to make sure you get a new chain when you replace the rear cassette. Depends on how stretched the chain is, there is a tool for checking that. I've got away with it in the past.