Confused about 15" wheels/backspacing going to 8 lug - help

[shewheeler]

Confused about 15\" wheels/backspacing going to 8 lug - help

Hi everyone.

I'm in the process of gathering parts for a 3/4 ton axle swap on my K10. I've got things figured out for the most part, but I'm confused about what wheels to run.

I sort of did things backwards and got the tires first (thanks again, Mychal /forums/images/graemlins/smile.gif ). They are 37x12.5x15 SSRs. From what I understand, with 3.5 of backspacing, minimal grinding will be required on the front calipers, but less backspacing makes the tire stick out farther, correct?

I want to try to keep the tires under the fenders as much as possible. I don't plan on running anything taller than the 4" lift that is on there now -- I realize that I will need to get some creative body work going on the fenders.

So, I guess I'm wondering if I should go with a 15x10 or 15x8 wheel ... 3.5 of backspacing or something different? I just hate to spend the $$$ on wheels and then hate the way they look/function.

Recommendations? Advice? Pictures?

Thanks!

 

[GMCLegacy]

Re: Confused about 15\" wheels/backspacing going to 8 lug - help

im unsure what backspacing in run, but if i were you i would run a 8" wide wheel, especially if you are attempting to keep them under the fenders.

 

[yunit]

Re: Confused about 15\" wheels/backspacing going to 8 lug - help

I think on the D44 you really do not have to do any grinding to fit 15's. I would look into getting 4.125" backspacing to keep the tires in. I have 4.125' backspacing and my 38's stick out about 2".

 

[Triaged]

Re: Confused about 15\" wheels/backspacing going to 8 lug - help

I have 15x10 Eaton's with 3.5" BS.
You can see how much they stick out in my webshots.
My tires are listed as a 12.5 but are actually more like a 13.5" wide tire.

3.5" BS (or less) is all I would use with a 15" rim on a 8lug. I do not like to weaken things like the brakes! If you want the tires to stick out less get a narrower wheel. I think a 8" wide wheel would work better with a 12.5" tire any way (I almost wish I had gone narrower with mine).

I had to do minimal grinding on the calipers in order for it to fit. In fact one of my calipers had lost more due to rust than for grinding to fit. For the backing plate I did almost no grinding at all (most people grind more on the backing plate than the calipers). I got it to fit by bending down the tabs that are on either side of the caliper. I then had to open the slot back up so that the caliper would fit. This did 2 things for me:
1) I did most of the "grinding" on my backing plates with a file.
2) Most calipers are groved from wear and by bending the tabs down they now ride on a non-groved part of the caliper helping them slide better.

 

[jekbrown]

Re: Confused about 15\" wheels/backspacing going to 8 lug - help

8" rims generally help to allow bigger tires to stuff in the wheel wells, yes.

As far as backspacing goes, the lower the backspacing number, the more room you have for brakes and the less grinding you would have to do if any at all. For instance, on my D60 I run rims that have 4.25" of bs on-road... to fit them i had to grind a LOT of material off my calipers. Off-road i run rims with just 2.5" of backspacing... with them on there is PLENTY of room for the brakes. Simplistic answer, but hopefully that clears up some confusion...

j

 

[outlaw612]

Re: Confused about 15\" wheels/backspacing going to 8 lug - help

Im running 15x10's with 36x12.5x15" TSL's. The rims have 3.5" BS. Personally, after seeing them on my K10 I wish I had gone with 15x8's. I did have to grind the front calipers, but not much.

These rims/tires stick out about 3" on each side, I dont like the way that looks.

 

[BadDog]

Re: Confused about 15\" wheels/backspacing going to 8 lug - help

Some answers may be found here. ¾ ton stuff is similar.

I like narrow wheels, I run 4" b.s. 8" wide wheels with 42x15x15 TSLs. But that has issues. They "caress" my steering box at full lock and get awfully close to other stuff as well. I run no inner fenders (well, no fenders either) and modified things to clear. However, I've run 5 psi without bead locks and folded the side wall completely under (with witnesses) without popping a bead. On a street rig the narrow wheels will cause crowning and tire wear issues. If you drive on the street much, I would say go with the narrowest manufacturer recommended wheel...

 

[shewheeler]

Re: Confused about 15\" wheels/backspacing going to 8 lug - help

Thanks for the info everyone! I guess I'll be sportin' 15x8s /forums/images/graemlins/smile.gif

BadDog -- great write up -- thanks!