October 6, 2006I'm putting 35"/12.5/15 BFGs on 15" x 10 rims on a 1973 CJ. I'm trying to figure out if I need wheel spacers, yaddah, yaddah. How the heck do I mathematically figure this out? Other than guessing, which is my normal SOP.
Forums : Tires & Wheels : Determining backspacing (483 Views)
October 6, 2006Dana, any good rim shop should have the bolt on contraption that can figure that out for you. It's adjustable and simulates a tire to where you can turn it lock to lock and adjust as needed. Where are you buying your rims from or are you using rims you allready have? I guess if you allready have them then this wont help.
October 6, 2006Well, I can tell you my 33's on 10" rims rub a bit on the frame in the front and the inner fenderwell in the back. Not enough to worry about. Something in the 1" to 1 1/2" range should work well for you.
My post for the week
October 6, 2006Already got them, and, of course its difficult to get a vehicle to a rim shop without tires and rims on. I can put the tires on and guess what spacers to get, but I was hoping for a more math like solution. Factory backspacing was about 3-3/4" but smaller tires with same size rims.
October 6, 2006Thanks Dave...your vehicle is a great comparison. Its nice to have an educated guess!
October 7, 2006Dana, I run 1.5 inch spacers in the back of my CJ and that has stopped the rubbing. I used to run them in the front as well before I put in the wide-track Dana44. When you order, make sure the inside hole of the spacer is large enough to go over your hub [or fit a centercap]. When I got mine, the fronts would not go over the WARN hubs and I had to have the inside machined out a bit by Doug Chartier.
They are fairly expensive hunks of aluminum however.
BTW - I run 35x14 on 10" rims
October 7, 2006^ what he said
October 7, 2006What???
3.75 - 1.5 x 2 + 2.5 / 3 != 2.25
3.75 - 1.5 x 2 + 2.5 / 3 would be 3.75 - 3 + .833 or 1.583
Now ((3.75 - 1.5) x 2 + 2.5) / 3 does = 2.33 is that what you meant?
Are you sure you weren't managing that Chemical Plant?
October 12, 2006I'm going to order the spidertrax wheel spacers... nothing online gives the "interior" diamater. Does anyone know if their spacers fit over the Warn hubs right out of the box.
October 12, 2006Edit***
October 13, 2006OMG! Here guys lets just make it easy. Check out the link, its easy to read.
October 13, 2006The actual question was whether this actual product would physically fit over my actual hubs. Another jeeper had bought spacers with an inadequate interior diameter and had to have them machined to fit over the hubs. Thanks, anyway. That is a good article on determining backspacing.