Hey guys,

i read in the FAQ section that to clear 12.5" wide tires i need 3.75" - 4.75" of backspacing. my question is dont you have to take into acount the diamiter of the tire as well? if so, what backspacing should i need to have if i want 12.5" wide 35's, and also 12.5" wide 37's. another thing i would think would come into play would be the width of the rim. because if you have a 12.5" wide tire, it would be a different distance from the edge of the tire w/ 8.5" wide rims than w/ 9" wide rims. i would think there would be a whole .5" difference. am i right?

 

I am no expert, but I do not think it's as complicated as that. If you are going 12.5" wide then you need at least 4.75" of backspace regardless of 35" or 37" tires. Narrower 8.5" wheels will help with flexing off-road. Wider 9" wheels will make it more stable on the road and add a little height. Backspacing requirements should not change with wheel width only tire width.

 

you are probobly right. I am probobly just over thinking it. Anybody else have some thoughts?

 

Porters is correct in that BS takes wheel width into account already. i.e. it's the distance from the flange to the inside edge of the rim.

But, don't forget that you'll be steering too. Larger diameter tires may require less backspacing in order to prevent rubbing with the steering cranked.

Chris.

 

Your backspacing isn't going to depend too much on the height of your tire. But, if you compare a 12.5" wide tire on an 8" rim with 4.5" of backspacing to a 12.5" wide tire on an a 10" rim with 4.5" of backspacing. The 10" wide wheel would make the tire stick 2" further out of the wheel well. To make the 10" wide rim have the same apperance and clearance as the 8" rim you would have to make it a 10" with 5.5" of backspacing.

To determine what backspacing you need you will need to know what size tires you want. And you should be able to figure out the correct spacing based on how wide the tires are. I went with the 4.5" backspacing on an 8" rim because I wanted my tires to stay under the flares. I had seen others running the 8" rim with 4" backspacing and they were hitting the outter edges of thier flares when offroading. This may not be a problem for you depending on tire size/ lift/ and wether or not your actually going to disconnect the sway bars and wheel it.

 

From everything that I've read on here if I go with a BB, 35x12.5", and a 8" wheel I will need 4" of back spacing. I have the bushwacker fender flares, so I shouldn't rub there. But am I right that this combo will prevent steering rub, and clear in all the appropriate places.
-Chris

 

what about a 35 that is 14.5 wide and on a 10" rim?