There are "extra" tires parts to repair, it's kind of a bug/unfinished thing. Some vehicles have more than 4 tires and need those repaired, others, that use four wheels, will still have the middle repair tires options, which you can safely ignore, as they do nothing. As long as the front and back wheels (on the scroll wheel menu) are repaired, you can drive your vehicle. Your fine, long as you see visible tires on each spot, your good.