Here’s the deal:

New Shimano 105, 11 speed chain: Around £20

New Shimano 105, 11 speed cassette: Around £20

New Shimano 105, 11 speed chainrings: Around £70

You chain runs through your cassette and chainrings. If it’s full of muck, grime, or just old and disintegrating, it drags all of that muck through the cassette and chainrings, a bit like that apricot exfoliater you use on your legs.

Cleaning your chain, and replacing it when it needs to be replaced, will make the cassette and chainrings last much longer – saving you about £90. Hey presto.