Backspacing for steel wheels

[likaroc13]

I currently have two 15x8 Vette style rallys with 4.25" backspace, which I was planning to run on the rear of my '97 Tahoe. I'd have to buy 2 wheels for the front. The Summit version has 15x7 with 4.25" backspace & +6 offset.

However, I'm really leaning towards running a set of 15x7 steel smoothie wheels such as the Wheel Vintiques 12 series:
http://www.wheelvintiques.com/index....re-finish.html

The only backspace option I see available is 4 inches, & offset looks to be 0. I was wanting to run a 235/70 tire up front. I have 2" DJM spindles & 2" drop springs.

The rear I wanted to do a 15x8. The only backspace option I see for that is also 4 inches, however it looks to have -12 offset. I was planning for a 275/60 tire out back. The rear has a 6" flip kit.

Will I have issues running either setup? Thanks for any help/input!

[1badgmc]

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[likaroc13]

I just chatted with Summit Racing, & I was told that they can do a custom backspacing & offset. I wasn't sure if that's possible or if I could only order what's shown in stock. So now I need to know what the ideal backspacing & offset would be for both front & back using the wheel/tire sizes mentioned above. That is 15x7 front with 235/70 tire and 15x8 rear with 275/60 tire.

[likaroc13]

Anybody know the backspace & offset on the factory 454SS/Sport wheels?

[dragginmetal]

Check out post #4.
http://67-72chevytrucks.com/vboard/s...d.php?t=599692

[likaroc13]

Originally Posted by dragginmetal

Check out post #4.
http://67-72chevytrucks.com/vboard/s...d.php?t=599692

Cool, thanks for the info. I forgot to update & mention that I was told the backspacing for the 454SS/Sport wheels is 4.25". However, based on my calculations, that doesn't give a 13mm or 0 offset. Maybe I'm calculating wrong?

[dragginmetal]

454ss- 15x7 0 = 4.0 b/s
Sport- 15x7 +13 = 4.51 b/s
That came from info packages I have.
I've never measured one myself, so I can't be 100% sure.

[likaroc13]

Originally Posted by dragginmetal

454ss- 15x7 0 = 4.0 b/s
Sport- 15x7 +13 = 4.51 b/s
That came from info packages I have.
I've never measured one myself, so I can't be 100% sure.

That's also what I get based on the math. The 4.25" backspace I was going by yields 6.35mm offset. I've come across several threads with comments of guys running the SS wheels with 255/60/15's on a 4/6 drop. I don't see that being possible up front with only 4" backspace. My stock spare has 4", & the 235 tire on it is pretty close to the fender lip. So, they must have the wheels with the 4.51" backspacing.

Based on what I've figured so far, I was leaning towards front wheels in 15x7 with 4.5" backspace just to be safe. That should sit inside the fender nicely with a 235 tire I think.

For the rear 15x8 wheels, I'm told 5" backspace would be the least I could get away with using a 275 tire. I'm thinking I'll go with 5.25 or maybe 5.5" backspace to be safe.