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Old 02-24-2010, 12:14 AM   #8
djmachinist
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Join Date: Feb 2010
Location: Katy, Texas
Posts: 253
Re: 15 x 8 Rally Wheel back spacing

Quote:
Originally Posted by lolife99 View Post
Just curious why you are stuck on 4" backspace.
What are your plans?
Lowering?
Air ride?

Alot of your suspension details will determine the wheels you can fit under the fenders.
And the width of the rim will determine the needed backspacing.

Alot of people say that Coys wheels or Torque Thrust II wheels are "played out".
I hate that term.
The real item that is "played out" is wheels with the wrong backspacing.

The trucks already have a wider track width up front from the factory. Just look at your truck from the front or the back, you can see it.
Now add disc brakes and the front gets wider than the drum brake set-up.
Then lower it and it gets a little wider, due to the lower a-arm being more flat or horizontal.

Meanwhile the rearend stays the same. The 67-70 truck have a narrower (.750" per side) than the 71-72 rearend. This make the front seem worse!

So,... my real question is,... what width/diameter wheels to do you plan on running?
A 4" BS on a 7" wide rim up front will work up front,... but will a 4" BS on a 10" wide rim work?
Keith,

I'm not stuck on 4" back spacing. I was going by the 15 x 8 6 lug rally wheels I have on the truck now. I was told they had a 4" back spacing, hence the desire for 4" back spacing. I plan on putting outlaw II's, 10"x 15" on th rear and 8" x 15" on the front. BF Goodrich Radial TA's, P275x60 R15 Rear and P255x60 R15 in the Front. Looks like I had the backspacing wrong so the back spacing of the the outlaw II's appear to be ok at 3.75".

If you are interested in my build Plans, Please look a few threads down, I posted my build plans earlier today. See thread titled "1969 GMC Build"

I would appreciate your input.

Thanks,
Dale

Last edited by djmachinist; 02-24-2010 at 12:15 AM.
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