If I was going to use a 15x8" wheel with a 4" back space would changing to a 10" wide wheel change the back space needed? Thanks

 

since backspacing refers to the distance from the hub mount face to the inward edge of the wheel, a 4" back spacing on a 10" would mean it would stick outside the body more than an 8" wheel but the 4" dimension would remain constant.

Its the metric offset that is the tricky one since the wheel offset is determined from the wheel center line; thus the width is split at 0.

Google Image will give you a million examples. Er actually 50,200...

 

Do the arithmetic, if it's a 8" wide wheel with 4" back space, the hub is just about in the middle of the wheel. If it's a 10" wide wheel with 4" bs, there's about 6" of wheel outside the hub an 4" behind the hub.....back space.

 

So I'm looking for a 10" wheel with a higher # back space 4.5/5" so not to stick out any further then an 8" wheel???

 

I put 10" with 4" bs on mine, it causes more rub when turning (trimmed it since). The wider rim swings in a larger arch when turning. The thing looks wicked with the extra width,( gives cool factor to dad when it's his 13 yo sons project!! )

 

You want 4" backspacing or less if you plan to run a tire bigger than 31x10.5. The width or diameter of the rim has NO bearing on the amount of backspacing required.

 

I am running 31s on stock wheels now. I'm looking to use 33X12.5x15 .I don't want them sticking out too much but I also will need inside clearance. I'm unsure weather to use an 8" or 10" wheel and also how much back space for each size.

 

Haven't we had this 8" vs 10" wide wheel with a 12.50" wide tire discussion before???????

 

backspacing does not change. check this out:

https://www.rsracing.com/tech-wheel.html

 

It seams some people just can't answer a legitimate question. If I new the answers I wouldn't ask the questions. Im sure there have been 8 & 10" wheel questions before.If you can take the time to be sarcastic why not just answer the question if you can. Most guys are helpful on this forum. Thank you to them.

 

We're not being sarcastic.....look at the area of your XJ where the tire/wheel mounts. That area was designed around a stock tire less than 9" wide and slightly over 28" tall so that the factory wheel back space of 5.25" tucks the tire/wheel into the fender area without anything rubbing and not sticking out either. Now, u want to stuff a tire that is 12.50"-13" wide and 33" tall in that same space......ain't gonna happen unless the tire is moved out away from the inner fender and that's what back spacing does, moves the tire out for clearance. Get your tape measure out and start measuring. The center section of steel wheels can easily be cut out and repositioned/rewelded to a custom backspacing.

 

I know I can't put a larger tire in the same space they would have to stick out, and I know what back spacing does. My question was to someone who has had experience in putting 33x12.5s on an XJ to suggest a back spacing for an 8" and 10" wheel,( not sure which one I should use yet), so I would have inside clearance with the least amount of tire sticking out. This way I wouldn't have to take a chance of making a mistake in measuring, and ordering the wrong wheel. That was my question. I'm not looking to build custom wheels. It's a dd and will never see any off road. Just wanted a suggestion. Thanks Frank

 

4" on an 8" wide maybe, maybe 4.5" on a 10" wide. But i would stick with 4" either way

 

Thank You. What size are your wheels and tires?Looks good

 

Key word is "maybe". 4.5" BS on a 10" wide wheel is going to have 1/2" LESS inner fender clearance than the 4" BS on a 8" wide wheel. That's why I'm saying measure it. The closer u get the tire to the inner fender, WITHOUT rubbing, the less it will stick out.