33x12.5" tires - recommended wheel backspacing?

Hey Folks,

Having ordered my 5.5" Superlift kit, I was planning on running 33" tires and ordering them in advance, but could use some advice on backspacing. Looks like the stock rim backspacing is 3.75" (6.5" width?).

I am concerned about wheel bearing life and tire contact with the fender/swaybar, and would like to keep them mostly under the fenders, but also realize that stability may be a factor thus less backspacing may be desirable.

Checking my local shop:
Eagle 589 15x8 in a 5 on 4.5 pattern are only available with 3.25" backspacing

American Racing Baja 15x8 in a 5 on 4.5 are available with 3.75" backspacing (but are more pricey)


What lift, width and backspacing do you run with 33's?
Any tire contact?
How are the bearings holding up?
Also, if you run 35's, what sort of width and backspacing?

Super thanks!
Malcolm

 

[Eddie X]

I also have questions concerning backspacing. When I built my '86 Bronco II, I ordered Centerline Protrucks with 3 3/8 because that's what the tire store recomended. They stuck out way too far. (10 inches wide rim). I want to run 10 inch rims with the most backspacing possible with 33's or 35's. If anyone is running the 'stang rims that apparently don't fit, what is the backspacing on them?

 

[Byrd91]

The 15x8 with 3.75" of backspacing will be the best happy medium. You may need to trim the rear of the front fender a little (or even just the fenderwell plastic) but it will keep you out of your sway bar and other internals and also be not too bad on the bearings. The stock wheel is 15x7 with 4" or 4.5" of backspacing.

Eddie, Everything I have heard on this board is that 15x8 is a lot easier to run than 15x10. Just like the Brono II they'll stick out and make it a lot more likely to rub the fenders, not to mention bearing stress.

 

[Joe Dietz]

I use 15x8 / 3.50 backspacing. I had to have mine custom built. I used stockton rim and went with a steel directional rim. I had the rims custom powder coated to match my truck.

The tires do not stick out too much.
The tires do not rub on the superlift radius arm.
The tires do not rub on the front sway bar.

I did decide to cut my fender down.

Everything looks stock and works great.

It did cost some $$ custom rims are expensive.

 

[RangerX]

Originally posted by Byrd91
The 15x8 with 3.75" of backspacing will be the best happy medium.

I agree with this.
3.75 is the most common backspacing on aftermarket rims.
And for 35's, use the exact same setup.

 

[malcolmzilla]

Thanks guys, sure appreciate the help.

I ordered AR Baja 15x8's with 3.75" backspacing, BFG MT's were 3 months backordered, so went with 33x12.50 General Grabber MT's, and am having the center lugs custom siped.

It's good to know that the rims will work with 35's, too, an option once the 4.56's go in!.

As for the trimming, it's just the plastic inner fender?

Malcolm

 

[FAKRWEE]

This is a good site to find info on backspacing and how it affects your rig. Enjoy.
http://www.4x4wire.com/tech/wheel/wheelfacts/

 

[Joe Dietz]

Not required -- I took out two inches of metal between the fender and the door on the front fender. I had to make some custom plastic inserts

Other folks have cut out the fender and then add the Bushwacker fender flairs. Search around on the site...There are a bunch of rigs with this mod.

enjoy your 33's

 

[malcolmzilla]

Lift is on and the 33x12.50's on 15x8 with 3.75" B/S work good.

Rears tuck in nicely, fronts hang out a bit, looks like there will be some contact on the rear of the front fender under flex/compression, but clears the swaybar and radius arm @ lock to lock, and still steers tight!

Perry's glass fenders should cure both issues.

Will test with my dad's tractor lifting one wheel @ a time, likely have to fab longer rear bump stops (fronts were supplied).

Thanks again, will post pics soon!

Malcolm

 

[ajevenson]

Which rims did you end up going with? Aluminum or steel? Good to see another Calgarian...

 

[malcolmzilla]

AJ,

I went with American Racing Baja's in a 15x8 as opposed to the Eagle Alloys. More money, but they had 1/2" more back spacing (3.75" - trying to save my wheel bearings).

Haven't had the truck off road yet, still working out some bugs, and fabbing the front receiver and wiring for my multi mount winch, tracking down a skinny 33" spare, extending vent lines and fabricating sway bar disconnects.

Checked out your site, let me know if you want to swing by and have a gander at the lift kit results.

Hoperfully will make it out for the AURS cleanup @ the airstrip on Sept. 14.

Malcolm

 

[ajevenson]

Definately want to see the results and how it went. Good to know someone that's done it. I'll PM you later this week or next when I'm back in town.