The must have item for cyclists that commute. The difference in quality of locks for bikes is vast, the more you spend the more secure the lock. Sold Secure is the logo you want to look out for. Many locks have their own grading system on the packaging which has relevance within that brand but the Sold Secure logo means it has been tested by an independent body. These tests include attacks on the lock using saws, bolt croppers and picking of the lock. Only the better quality brands have this testing done as it is expensive and is one of the reasons better locks cost more.
There are 3 levels of Sold Secure for locks for bikes, Gold, Silver and Bronze. Gold being the best. The main brands that offer these levels of testing on their product are Squire, Abus, Magnum OnGuard and Kryptonite.
Many of these locks for bikes are either D locks or Heavy duty chain locks. Many don't wish to carry these heavy locks so you then have coil locks and cheaper versions of these more expensive heavy duty locks. Most of these coil locks won't have Sold Secure testing but this doesn't mean it is a bad lock. They are more affordable and for many, more useable. The materials used also help to keep the price down with these locks. Cheaper grade steel is used and the barrel housing for the lock itself is quite often plastic rather than metal. These still work as great deterrents at school or in town and many use them as a secondary lock to go with their higher quality lock. The more you have, the safer your bike will be.
Nearly all locks for bikes come with a mounting bracket so you can attach it to the frame whilst not in use. If you don't have room on the frame many put it in their pannier bags or around the handlebars or seat post so, consider what shape lock you purchase carefully as frame fitting is a much safer option than hanging off your bars. Brands like Abus now make locks that will fit in your pocket that have the Sold Secure testing so there is always somewhere to put it.
Sadly, Bike theft will always be a problem so you will always need a lock if you intend leave your bike anywhere. Our recommendation is to spend as much as you can on your bike lock. It genuinely will make a difference.