View Full Version : 1990 Prostar Trailer - 15" Wheel Upgrade

06-23-2007, 10:57 AM
I have a '90 Prostar 190 that I trailer quite a bit. I have been having problems with tires blowing out on the highway and decided that there was just too much weight on those little 14" tires once my boat was loaded with skis, boom, pylon, etc. I read a thread here last year about someone upgrading to 15" wheels/tires, so I did it. The thread said that they just added a 1" shim on top of the axle; I did this, and I have plenty of clearance between the top of the tire and the fender, but the inside side of the tire has very little clearance when stationary, and when I bounce the trailer it rubs. It also appears that one side has more clearance than the other. It looks like if I modified the fenders I could make it work, but I would really rather not do that... does anyone have any suggestions?

06-23-2007, 12:03 PM
The only reason you should have any rubbing from changing wheel diameters from 14" to 15" is you went to a tire that had a larger diameter and width or you went with a wheel that had the wrong offset. On a trailer the backspacing should be near 1/2 the width of the wheel for a proper wheel bearing load. I run 15" X 8" wheels with a 3 15/16" backspacing.

06-24-2007, 01:26 PM
Yeah, they are a D load range tire that is definitely wider (and they are radials as opposed to bias ply). I also noticed that the fenders are not mounted the same distance from the wheel on each side... I think I can take a little off the inside edge of the fenders and move them in and away from the tires, not sure if that will work though.