I agree with Ron Bissett concerning hubcaps on trailers. People at the roadside rests must think I'm a nut when they see Me going around My 5vr feeling the hubs. This is one way one can find a potential hot bearing or a brake dragging. Hub caps look nice, but do keep some air from cooling Your wheels at the bearings and drum areas. Many premature bearing failures have been found this way. Just My experience here.