Rim Offset?

I have to take the plunge for new tires soon. I'm considering B.F. Goodrich M/T's size 32x11.50 - 15. I have 15-10 rims ( from my long gone F-150) with 33 x12.50's on now. I don't know the offset on these rims but I think that they will be a little wide for the new tire and they now rub the springs on sharp turns. I'd like to go with a 15x8 rim and would like to get an idea on what the proper backspacing should be. Thanks for the help.

 

Don't quote me, but I think standard is 3.75"

 

Oddly enough, I went through this with my local Discout Tire. Their "standard" backspace is listed as 3.75", but the actual measurement is 4.00". I'd personally measure the rim for backspace rather than rely on the numbers in the catalog just to be sure.

Check out....
http://www.bfgoodrichtires.com/assets/pdf/mud_terrain_ta_km.pdf

"section width" will be helpful. With this, you should be able to do the math and figger out what would work for you. For example, if you're running 12.5's and are going to 11.5's, you'll gain .5" clearance with the same backspacing and same width rim.

Also see....
http://www.rsracing.com/tech-wheel.html

for how to measure offset, backspacing, etc.


HTH

 

Depending on when your wheels were made the backspacing will be from 3" to 4" in the old days most 10" wide had 3-3 1/2" backspacing, most 5 on 5 1/2 rims are backspaced for Dodge pickups now and are gonna be 3 3/4 or 4" . I have run 11.50 on 10" rims with no problems even with 10.50 on 10" rims only lost bead if aired down less than 10# but I probably didn't push as hard as some. Maybe adjust steering stops to allieviate "rubbage"?

 

If someone was to go with more backspacing.........would this give the jeep a wider stance? Does more backspacing position the tires out more?

 

Yes, backspacing affects how far out the tires sit. The LESS backspacing, the FURTHER out the rims sit from the center of the vehicle.

The MORE backspacing, the CLOSER the rims sit to the center of the vehicle.

See
http://www.rsracing.com/tech-wheel.html

 

Good points JD7 - that is a concern of mine 'bout the 10" rim losing the a bead when aired down. I don't think I'd find myself below 10 psi often and I tend to drive on the conservative side because I hate to pay for repairs. The rims I have are fine and maybe an 1" narrower tire could only help minimize the rubbing - right?

 

Be careful, not all ford 5 on 5.5 fit Jeeps.

Karl

 

In aftermarket wheels most have the 4 1/4 center so they can.

 

when i got my new tires, the guy on the phone asked if i had locking hubs, because the hole is bigger.

 

I guess I was speaking of ones such as American and the type you can buy for a weakly payment at Ottasco. I bought some from 4Wheel Wholesellers to get an offset that I wanted and they ask me to specify the center whole diameter and what they were going on, but that was what I think of as a semi custom option. Stockton is more of a custom option, at least in my book. I think of Stockton as a custom manufactorer of wheels. Those that only want the best and are willing to pay for it are the only ones with Stockton wheels, right

 

I run 33X13.50's on 10 inch X 2.5 backspaced rims and they do not rub anywhere.....I have flexed it very hard and bumped the back corner of the fender on the rear.
My old 33X12.5 on 10 inch with 3.75 backspacing rubbed the fenderwells in the rear....