Bike shifts down badly

[screenman]

They certainly should as it is only a 5 minute job.

 

[mattobrien]

What would you consider the limits for a cassette and chain? My bike has probably do e 1500 miles since new in August but shifting down doesn't always happen smoothly.

Sorry in the delayed response. Some may suggest that a chain may have served its purpose after 1,500 miles and could need replacing, checking for wear if nothing else. A cassette ought to last longer, as long as it is not used with a worn out chain.

I have a chain wear measuring device on my internal xmas list.

 

[Shut Up Legs]

How many times do I have to post this on the forum for people to understand it?

It's not the chain or cassette or the derailleur hanger, it's the derailleur cable where it curves round to the derailleur; it becomes sticky and gets crudded and rusted up, especially in winter. It needs replacing at least every six months in order to maintain performance. Get your LBS to cut you a metre of cable outer then cut it into the same lengths as the existing cable then keep them in a safe place.

Once you've changed the outer and cleaned up the inner you'll be amazed at the improvment in shifting.

Rust? Not on my bike, I don't allow it .