8 ft bed for a 5er so it wont crash into the back of the cab when you turn too sharp. Anything less than an 8 ft bed you will need a slider hitch to avoid damaging the 5er and the back of your cab. Some expert wannabes like to brag about not using a slider hitch on short beds until their 5er hits the cab. Only a matter of time. For those that recommend a short bed and no slider hitch let them know you will holds them financially responsible for any damage you may run into for following their advice.