OneFreakZ

hey guys i bought some zr1 wheels silver painted for my 89 camaro now i wanna put 17x11 on the rear and the front 17x9 does any one know what wheel spacers are needed to put these wheels on???..thanks for your help..

Injuneer

Depends on the offset of the ZR1 wheels, there are at least two different offset versions of both front and rear wheels. The fronts are 17x9.5", not 17x9.0". You would need the exact offset to calculate the spacer size.

The 3rd Gen rear axle assembly is somewhere between 3" to 4" narrower than the 4th Gen rear, so you would be looking at 1-1/2" to 2" spacers. You can get them here:

http://www.skulte.com/

OneFreakZ

yeah i think they are 56mm offset..i found some 2" spacers on ebay for cheap i just wanna make sure that i need the 2" spacers...thanks

Injuneer

Somehow, a set of 2" spacers doesn't seem like the best place to go "cheap".

The 3rd Gens also have a different offset requirement front and back on some models, and some of them came with a spacer on two of the wheels. Skulte knows the exact details, and can not only supply a set of high quality spacers, he can insure you get the EXACT required width.

Lonnie Pavtis

I just put a set of wheels on my 91 Formula & researched this extensively.

I would recommend to actually measure your needed thickness instead of taking anyones advice on thickness. There are a lot of people suggesting 2" spacers, but I wasn't thrilled with the amount they stick out on a 3rd gen.

275/40-17 will clear with a 9" wheel on the front with the correct offset if it is not lowered. The 9.5" wheels hurt you here & may hit.

I tried a set of '02 Firehawk wheels w/ 1-1/4" spacers & they touched the tierods on my car. I would have used 1-1/2" spacers on the front so they do not stick out as far. The rear could be thinner if you desire.

I currently have 3/16" from the tie rod to the rim, which is a little tight, but it has not been a problem.

The brand of wheel, thickness of the aluminum & the radius of the inside corner of the rim will change the spacer thickness. Try to find some assorted pieces of tubing (that slip over the studs to extend them) & some washers to mock up the wheel at different spacer thicknesses. When you are happy with your measurements, get the spacers to match.

The rear will require a differnet thickness as well.

I ended up with an overall backspace of 6" at the rear & 5-7/16" at the front to tuck the tires in as far as possible. Depending on your brand of tires & inner fender mods at the rear, you may need something different.

OneFreakZ

cool well the zr1 wheels that i bought might be 56mm or a 50mm offset but im not sure all i know is that the wheels came off an ss camaro 00 or 02..thanks for your help..

Lonnie Pavtis

Well if they are SS wheels, they are 9". These have the best chance of working with your 3rd gen. A 275/40 will clear in the front, but lowered cars still may touch when fully turned. 9-1/2" was a Vette wheel.

Throw a straight edge across the back of the rim & measure to where the wheel touches the hub. This measurement needs to be less than 5.5". For example..... 7" backspace -(1.5" spacer) = 5.5". You likely will need 5-1/4" to 5-1/2"max to clear the tie rod.

As stated earlier, I'm at 5-7/16" on the front & everything clears perfectly even with a 285/40-17 BFG KD's. You may have to clearance the corner of the strut near the top of the rim as well, if using this much backspace. There is a tab above the spindle mounting bolts that is close to the rim.

For the rear, I'm at 5-7/8" BS. I flattened the inner fender at the front edge for tire sidewall clearance to keep them tucked as far as possible. Your car may vary depending on how centered the rear is. Measure to be sure.

Hope this helps.

Injuneer

Lonnie - Have you ever measured the actual difference in width between the stock 10-bolt in a 3rd Gen and the one in a 4th Gen? The Strange website drawing show the difference as 3", but I've had people tell me that's not correct, and that the 3rd Gen is 4" narrower than the 4th Gen.

OneFreakZ

cool lonnie thanks that did help...

Lonnie Pavtis

Injuneer, I have my '88 Formula in the garage now. Putting a fuel pump in....
If I take the wheels off, I will get a measurement.

I always thought it was a 3" total difference.

There are a few differences in the 3rd gens as well....
Disc brakes, iron drums & aluminum drums that vary the width slightly.

My '91 has iron drums with factory 1/8" spacers..... supposedly to equal the thickness of the aluminum drums.

BLK96Z28

Lonnie, have any pics?

Lonnie Pavtis

I installed Chrome 17 x 9" Rebels on my '91. The tires never rub & it handles great. It added 5mph to my favorite 25mph offramp from 60 to 65mph before it gets crossed up.

I do not have any pictures at this time, but may take some this weekend if it is clean. It seems to attract rain....

Lonnie Pavtis

Injuneer,
The 3rd gen rear is 62" drum face to face. The Strange Engineering dimensions match once you add the drum thickness.

Injuneer

My copy of the Strange dimension drawing is fading, and the scan they have posted on their website is almost unreadable. I think they have the dimensions for the drum brake setup on one side of the drawing and the disc brake setup on the other, but the reference is to the end of the axle housings.

My read was it was a 3" difference based on the hub-to-hub measurement. but in the past, when I posted that info in response to a request for help, I've had 3rd Gen owners tell me I don't know what I'm talking about and that its a 4" difference. I'm just trying to get the exact number, so I can factor it into the discussions on wheel offset.

Thanks.

Lonnie Pavtis

Strange shows 61.72" to the axle flanges for the 3rd gen.
Add approx. 1/8" per side for iron drums & about 1/4" for alum drums.
I'm not sure of the factory disc setup thickness

The Strange rears are setup for the 93 up discs.

The 4th gen is 3" wider according to the Strange drawings.

I've never measured, but the 3rd gen body may be narrower than the 4th causing these claims of a 4" difference. I do know a 6" BS wheel on a 3rd gen has more inside clearance than a 7.5" BS on a 4th gen.
Hope this helps.