Cassette and chain

[Ajax Bay]

Its actually quite difficult to spot wear on a cassette, not so much on a chainring and near impossible on a chain without a checker. You'll have problems running a well worn chain on a new cassette. I have a significantly worn chainring on one bike but with a relatively new cassette and chain but it all works fine. Id wait until you get slipping before you decide to replace all.

Agree all except that running an old chain on a new cassette will be no problem. It's just that the elongated chain will wear the cassette faster and it's a poor choice, economically. Chainrings will wear more if you run a really elongated chain on them - but the OP's chain is likely <101% (I'm guessing - 1800 miles).

 

[Caperider]

My wife has a carbon trek SLX and it has about 10 k miles on if I've changed chain twice and still has original cassette no skipping or jumping. Its such a sweet bike its like 15 lbs. Without the water bottle. She rides the BeJeusus out of it! ! I can't keep up.but I kick her butt in the woods lol.

 

[silva]

Doesn't the position of the derailer give a clue about the chains elongation?

 

[boydj]

Doesn't the position of the derailer give a clue about the chains elongation?

No. Why would it? The elongation of a worn chain is a tiny percentage of the total chain length.

 

[Jenkins]

Its actually quite difficult to spot wear on a cassette, not so much on a chainring and near impossible on a chain without a checker. You'll have problems running a well worn chain on a new cassette. I have a significantly worn chainring on one bike but with a relatively new cassette and chain but it all works fine. Id wait until you get slipping before you decide to replace all.

Oh, I don't know...

 

[roubaixtuesday]

Man in shop he gives reasonable advice. With that distance cycled (1800 miles) the chain will have elongated and also worn the cassette. Both will need changing. If you just change the chain, the new one will slip on the cassette.
Echoing what others have said, if you periodically measure this new chain, and change it at (say) 1500 miles or when it's <0.75% elongated then a new chain will (should) not slip: you can normally repeat this and get 3 chains per cassette (then replace both together).
With the distance you say you've cycled, I am very surprised the chainring needs replacing. I'd expect maybe 10,000 miles, but maybe you do nearly all your riding in the large ring, in which case it'd be less. But 1800 miles: no.
Change chain and cassette and see how it rides, I would.

Wise advice he gives.