How much should you spend on a lock? The police recommend you spend between 10% and 20% of the value of your bike on a lock. If you've got a good bike, you need a good lock. When you're out for a ride, take a lightweight cable lock to stop anyone jumping on your bike and riding off when you're in the shop/cafe, but it won't stop anyone with a pair of bolt-cutters. A heavy-duty shackle or armoured cable lock is essential when you leave your bike unattended for any length of time in a risky area or at home. Ground anchors are also worth investing in if you leave the bike in a shed or garage, these provide a fixed point for you to lock the bike to and make it harder to steal. Another tip if leaving your bike locked up, is to lock it in a well lit public area, or an area with CCTV coverage, this will deter a potential thief from attempting to steal your pride and joy.