To get the proper Toyota Tacoma bed cover, for example, or any bed cover, you must measure your truck bed and find out your truck style. There are four main types: side step, regular cab, extended cab, and 4-door crew cab. Next, you should measure the bed length. It’s determined by the distance between the inside of the rear door and the inside of the bulkhead. Don’t worry if you can’t find the cover length that matches the length of your truck bed: it rounds off to the nearest half-foot. This way, if your truck bed measures 76 inches, you should look for a 6.5-foot bed cover size.