View Full Version : backspacing on rear wheels
05-03-2003, 04:39 AM
has anyone had a problem with running bigger tires, say 38x12.50 on 15x8 wheels in the rear of our rigs? my 36x12.50 are about an inch from the springs now, I'm worried that going up in size will give me problems.
05-04-2003, 12:19 AM
ok.. if you g up from 36's to 38's... you don't affect the width.... you may have more sidewall flex which can make it a bit closer.
the tire brand had much to do with that as well as not all 12.50's are 12.50's if you know what I mean.
05-05-2003, 08:33 AM
correct me if I'm wrong, but if you go up 2" in diameter you would in a sense be going wider for the front tires? They would be closer to rubbing the front springs wouldn't they?
05-05-2003, 01:42 PM
the rear springs are outboard of the frame, ie, way closer to the wheels. my tires are very close to the springs now, and I'm worried that if I go to a tire that is any wider that they might rub the springs all the time. the fronts only rub when turned to full lock, I'm not worried about that. maybe I asked the wrong question. I should have put it like this: Has anyone had a problem with tires rubbing the springs on the rear of their rigs. And if so, what backspacing did you go with in order to make them clear?
05-05-2003, 01:57 PM
yes, i did, but mine was from squeezing a 12.50 tire on a 7 inch rim. i just got wider rims form the yard.
05-05-2003, 02:06 PM
The wider the rim you mount the tires on, the less it will "pucker" and the more clearance you'll have to the spring. A 12.5" on a factory 7" rim is about the closest you can come to the spring (mine are 1/4" away from the spring in places). With an 8" rim, however, or less backspacing, it would clear better.
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