Choose the right lock. The level of security you need depends on where you are leaving your bike, and for how long. A combination lock is generally best for casual lock ups during quick pit stops. Combo locks are great for locking bikes to your auto racks as well. Just don't leave the bike out of sight for too long, nor lock it up overnight without something more secure. Don't know where to start? Read our guide How to Chose the Best Bike Lock.