On the subject of chains, here we have a simple piece of stamped metal which might not appear to do very much at first glance – but which could save you big money in the long run.

If you don’t change your chain in time, you can end up having to replace the rear cogs too – as they get eaten away by the widening chain rollers.

What to Consider When Test Riding a Bike

Designed to be slotted between the links, this tool tells you when it’s time to replace your chain – and whether you’ve let it go too far or not.

Price: £7.49, (RRP £9.99) available from Chain Reaction Cycles.