15x7,16x8, 4"bs, 4.5'bs, 17x8's oh my. Need some help

64malibu79

Amateur Racer
Aug 23, 2006
105
0
0
Brandywine, MD
I am having trouble wrapping my head around my current wheel issue, and hope you guys can help me clear it up.

Here's the setup; 1LE B-body spindle swap with Hotchkis A-arms, Hotchkis sway bar and 1" lower Hotchkis springs all the way around. I have been running 15X7 Z28's rims mounted on 225/60-15's, didn't have any troubles or rubbing. I decided after seeing some ZQ8's on here I wanted to run those, so I bought them, and they don't fit on the front as this has been discussed in another thread here. No problem, I should have done more checking before buying, not all's lost I can put them on my 80 bu.

So in my effort to find new wheels I would like to go to 17's, I like the Coys that Phillip was looking at for his son's car. So I decided I would measure things up this time to figure out what fits...well this has just made it more confusing for me. I took a piece angle iron drilled holes to mount it to the rotor then drilled hole for the rim diameter and the tire diameter I was thinking of running. So I have a hole at 8.5" from the center line of the rotor to give me my 17" wheel clearance check point, and another hole 13" from the CL of the rotor for the tire.

My trouble is it appears that the tire is going to rub my sway bar at full lock, and the backspacing is not clear to me either. I was thinking I would have to run a 17X7 w/4.5" BS, but I've read here guys running 17X8's w/5" BS. Both setups clear obstructions, but it looks to me there will be tire rub either on the inside or outside of the well. Currently my 15's have about 3/16" clearance at full lock from the sway bar and the 16's with 245-50's make contact but are at full lock as well.

I tried to figure out how long a piece of all thread to use to replicate the rim but when I measure my 15's it's approx 8 5/8" wide and the 16's are approx 9 1/2" wide so I don't know how to accurately replicate that #-o Also when I tried to figure out the BS of the rims it appears they both have around 4" of BS.

If you guys have a known size that works with the 1LE swap and 1" lower springs I'll run with that, otherwise what do I need to do to get the correct measurements??

One last thing, can you recommend any wheels that are not over $225, I really like the Coy's but it looks like I can't get a 17X8 with 5" BS if that is needed. I found some other rims that would work but they are in the $300+ range and that's out of my budget.

DSC00191Medium.jpg

DSC00192Medium.jpg

ZQ8 wheel with angle iron across the tire
DSC00187Medium.jpg

DSC00188Medium.jpg

Z28 with angle iron
DSC00189Medium.jpg

DSC00190Medium.jpg
 

StreetBu

MalibuRacing Junkie
Mar 21, 2004
4,158
3
38
Upstate NY
I dont have any bright idea's besides to tell you that the rim width is measured from inside bead to inside bead of the wheel. So if you measure the outside of the wheel your adding in the thickness of the wheel on inside and outside to the measurment.
 

LS6 Tommy

MalibuRacing Junkie
May 15, 2004
15,847
1
38
North Jersey
What steering box are you running? The stock box will often rub with 16+" wheels, even OEM GM ones. If you get an 80's IROC/WS6 T/A box it has steering stops set for the 16" wheels. There's also the bonus of the quicker steering ratio.

Tommy
 

64malibu79

Amateur Racer
Thread starter
Aug 23, 2006
105
0
0
Brandywine, MD
Thanks for the replies.

Tommy I am using an "XH" box from an IROC

I found that rims-n-tires website, that has been helping, I plan on mounting the Z28's up and measure how much additional clearance I have then use the R-n-T's website to figure out what size rim and tire I can use. I think it's going to end up being a matter of how much I want to spend on rims, some of the less expensive rims I can't get the correct BS with the larger width rim.

Just for someone's information I measured the BS of both the Z28 and ZQ8 rims and they both have 4.25". I took the measurements according to how it's described on the rims-n-tires website, FWIW. Z28 is 15X7, ZQ8 is 16X8.
 

MalibuRacing.com Gear

Stickers & Shirts!!

Latest posts