Is there any chance that that my 92 Z28 Convertible had these wheel spacers from the factory, or as part of the vert conversion?

Never seem before, on any of my other hard top/ t-top cars. Not sure if I should be tossing these aside. Yes I did confirm rear wheels on the rear

 

Common and not vert specific

 

Why? When I searched spacer all I found was adapter spacers. a spacer that small cannot be doing much?

 

Keep the wheel from getting stuck to the iron drum.

Work wonders.

 

Came on my 92 RS with the 16s, haven't seen them on any of the 5 other cars i've had. thought they were a 91/92 thing.

 

I've had them on several cars(all rear drums). I am not sure if they are on all rear drum cars or not. I'm sure most get removed or tossed at one time or the other...

 

GM added the .187 rear spacer to make up the difference between the Aluminum to Iron rear drum brakes. I had them on my 1987 car and it seems they were a hit and miss install on the assembly line. Some got them and others did not, but most got discarded over the years. Sold mine on E-Bay for $20.00 years ago.

 

That makes sense... kinda. No other vehicles I have run into have a "washer" between the wheels and drums/rotors. Why would some 3rd gens need this not others?

My 91 did not come with them, but it had aluminum drums factory. Never seen any other vehicle with these.

 

This sounds like the answer I was looking for. So I'm gonna leave them on there. Just wanted to make sure they were some add on thing or there to solve a problem I didn't know about.

Thanks guys!

 

There is spacer info in the 10-Bolt FAQ. BTW, my 85 J65 car was equipped with spacers.

JamesC

 

My car does not have them, but it might have at some time. I have heard about them, but never seen them. I also though GM out a spacer on the rear with the 16" wheel's to help make of some of the offset differance since the front wheels are 16mm neg offset more that the rears?

 

I'm pretty sure I have these spacers on my 89 Formula and I've been wondering if it is throwing the balance of the car off? The spacers aren't a tight fit on the lugs.

I just had all 4 tires balanced but still get a little bit of shimmy on the highway around 70mph. All the suspension bushings on the car appear new and the steering gear doesn't have play, so there really can't be much else that could be causing shimmy, right??

 

Probably not. Easy enough to tell about the balance though; take em off and see if it changes.

Nobody out here really knows why they're there. My personal suspicion, based on many decades in various mfg situations and bolstered by pure conjecture, is that they were there so that both drum and disc rears would be the same width and could be handled on the same production line by the same fixtures without alteration. IOW, once the vehicle emerges from the assy plant, they're no longer needed for anything, and can be discarded. In fact, one instruction in the dealer PDI list for these cars, may well have been to remove them, which is why not many cars have them... sometimes the lot monkey forgot to do that one thing.

If only...

Usual cause of that, is separated tires. Again, easy enough to tell; swap the fronts & rears on each side, one side at a time, and see if it changes.

 

Eh I don't think the tires are the culprit, they're new and high quality.

I know my sway bar links in front and back are toast but I can't see that contributing to shimmy really. Same with strut bearings - my passenger front rattles a little and it's on my list to change.

Next time I have the car up I'll just remove the spacers and see what happens. I'm not surprised they're there considering how original the car is - still has the factory lugnuts / covers, including one splined lug (with key) per wheel

 

:shrug:

Good luck with that then.