Nope just unplug the fronts from the valve stem and put the extra in the rear you want. The only time you will need to plug anything is if youre only using one side you have to plug the output where you would normally plug in the other sides hoses and the system (if its a good one) should come with a plug.Guys: if I want to inflate all four tires to 33 lbs, but then have my rear two go to 35, do I just unhook the front two tires at 33 and leave the back two plugged in? Or does this system just blow air out of each hose all of the time? Is there a closure valve on each hose end of are they “normally closed” until hooked to a tire? I guess the same question would hold true to inflate one tire on a friend’s vehicle. Thanks for the info!