I used to watch my dad load up the wheels in his truck and take them to the tire shop. Being too young at that time to realize why, I just took it as the right way. Then one day, after me and my friends were old enough to have trucks, I went with one them to the tire shop in my hometown. I watched the guys with their badarss air tools, floor jacks and all that. Reminded me of something from a NASCAR race. Anyway it occured to me that day, most people drive up with old tires, drive away with new ones...neato!! A little while later, I learned the hard way, why dad loaded his wheels in the truck and drove them seperately to the shop. The first time those numbnuts stripped and cross-threaded my lugs, and my dad made ME change and replace them...was the last time it happened to me.