New cassette and chain?

[DRM]

Put the bike into the largest cog on the rear, change gear at the shifter all the way to the last cog, but don't pedal, the gear cable will now be slack, pull the short piece of outer at the rear derailleur out of it's stop and slide it down the inner, check for frayed inner cables and also under the bottom bracket's nylon cable guide for frayed cable, if all is well try cleaning the inner cable, and flush out the short outer, with something like GT85 or penetrating oil, then apply a thin film of grease and put the outer back in it's correct position, change gear back up to the largest gear to tension the gear cable and try it to see if the gear shifting improves, if it does jobs a good 'un, if it's frayed then replace the cables.

 

[livpoksoc]

She just needed a thorough clean - just did a 15m circuit at lunch having given the drive train a proper clean last week. I didn't even notice the gears, that's how smooth it was.

Either way I have a new chain, cassette and cables on hand for when I want to have a go at redoing it further down the line.

 

[Ming the Merciless]

15 metres, think you need a longer test ride than that