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I'll be buying new jegs steel wheels with some of my tax return. I want the tires sticking out of the wheel wells more than they currently do, but for some reason I'm having an issue wiping my head around the back spacing. I'm running 35x12.5R15s. I am aware of the negative effects of too much and too little backspacing.
So, would the 15x8 with 3.75 inches of backspacing or the 15x10 with 4 inches of backspacing be preffered?
I know 8 inches is a bit thin for the 12.5 inch wide tires but they are currently on 7 inch wide aluminum wheels and I haven't had any issues (other than rubbing, which is why I want the new wheels and wider stance).
I'm also switching to that size tire and will go with the 15 x 8 steel wheels with 3.75 back spacing. Post up after you get them on and tell us how they fit.
I'll be buying new jegs steel wheels with some of my tax return. I want the tires sticking out of the wheel wells more than they currently do, but for some reason I'm having an issue wiping my head around the back spacing. I'm running 35x12.5R15s. I am aware of the negative effects of too much and too little backspacing.
So, would the 15x8 with 3.75 inches of backspacing or the 15x10 with 4 inches of backspacing be preffered?
I know 8 inches is a bit thin for the 12.5 inch wide tires but they are currently on 7 inch wide aluminum wheels and I haven't had any issues (other than rubbing, which is why I want the new wheels and wider stance).
Thanks in advance for all the opinions and help!
The 3.75 will stick out a little bit further than the 4 and also an 8 inch rim is perfectly fine with a 12.50 tire. I'm running the same setup except with 33s
Last edited by XJmike0122; 01-09-2015 at 06:34 PM.
94xj, our jeeps have the exact same coloring! Thanks for the pictures, that looks right bout where I want my wheels to be. Do you have any rubbing issues on the shock towers or control arms?
I adjusted the steering stops by adding 1 washer to prevent them from rubbing the paint off my long arms. They didn't rub the lugs of the tires, just enough to take the paint off.
My axle wasn't centered perfectly so every now and then when it got really stuffed on the passenger side the tire would take some paint off the shock tower on the front. Again, didn't rub, but it was just enough to clean the paint off.
It's on the to do list lol. I'm probably gonna be buying a new rolling chassis, mines falling apart. It was already pretty hammered up when I bought it. Im gonna start fresh and do a lowcog build. Also considering cutting the uniframe out and building a tube chassis.
Hey 94XJSport94, are your front quarters cut back to the pinch seam or past the seam? I'm running a 5.5 inch lift, 33s with 3.75 back spacing right now but am moving up to 35s in the near future. Like you said I know I'll get some spring tower and control arm rub but am wondering how far back (behind the front tire) the body work needs to get cut or moved to achieve turning block to block clearance.
No problem. I measured my wheels the other day because I was driving down a slushy road and had to use the windshield wipers the whole way. I needs me some flares. The front stick out 4 3/4 inches from the fenders and the rear is right at 4 inches.
No problem. I measured my wheels the other day because I was driving down a slushy road and had to use the windshield wipers the whole way. I needs me some flares. The front stick out 4 3/4 inches from the fenders and the rear is right at 4 inches.
Awesome. That sounds to be right about where I wanT mine to be.
Hey 94XJSport94, are your front quarters cut back to the pinch seam or past the seam? I'm running a 5.5 inch lift, 33s with 3.75 back spacing right now but am moving up to 35s in the near future. Like you said I know I'll get some spring tower and control arm rub but am wondering how far back (behind the front tire) the body work needs to get cut or moved to achieve turning block to block clearance.
The front inner fender? I made relief cuts and hammered it down flat. I didn't have any rubbing on my fenders when I had 35's. When I move to 39's I'll have to lose a little more sheetmetal. I was around 4.5-5" of lift I think.
The 3.75 will stick out a little bit further than the 4 and also an 8 inch rim is perfectly fine with a 12.50 tire.
Maybe I'm confused, which wouldn't be the first time. He said his choice was an 8" rim with 3.75" of backspacing or a 10" rim with 4" of backspacing. Wouldn't the 10" rim stick out stick out 1.75" more than the 8" rim due to its greater width?
At equal backspacing, I would expect the 10" rim to stick out two inches more than the 8". With .25" difference in backspacing, I would expect that to only be reduced by .25" to 1.75". What am I missing?
Maybe I'm confused, which wouldn't be the first time. He said his choice was an 8" rim with 3.75" of backspacing or a 10" rim with 4" of backspacing. Wouldn't the 10" rim stick out stick out 1.75" more than the 8" rim due to its greater width?
At equal backspacing, I would expect the 10" rim to stick out two inches more than the 8". With .25" difference in backspacing, I would expect that to only be reduced by .25" to 1.75". What am I missing?
Yes, a 10" wide wheel will be wider. A 8" wide wheel will hold a better bead when aired down with a 12.5" wide tire. There is no real need to run a 10" wide tire unless you like the look for some reason.
A 10" wide wheel with 4" of BS will stick out 1.25" farther than a 8" wide wheel with 3.75" backspacing. A difference of .25" backspacing then divide the difference in wheel width.
A difference of .25" backspacing then divide the difference in wheel width.
Why would you need to do that? The backspacing is from the mounting surface and is all on one side of the wheel, not distributed across its width. Also, .25" divided by a 2" difference would be .125", not 1.25".
Unless I'm confused, I think all you need here is simple subtraction.
If the 8" rim has 3.75" backspacing, the outer edge would be 4.25" from the mounting surface.
If the 10" rim has 4" backspacing, the outer edge would be 6" from the mounting surface.
6" - 4.25" = 1.75"
Therefore the 10" rim would stick out 1.75" more than the 8" rim.
01-09-2015, 05:05 PM
new wheels, back spacing question
