Jbuchanan

New to the site and new to owning my 87 GTA. Looking around my car today and found my spare tire. Never seen an aluminum space saver. What blew me away was the canister inflation system was with it. Just curious did all Trans AMS have this?

Jbuchanan

Drew

iTrader: (58)

Most if not all thirdgens with a G80 Positrack rear use an inflatable spare. When inflated, the outside diameter of the spare is the same as the regular tires, or close enough anyway to keep the differential from being damaged.

Then things get interesting because GM was looking for ways to save weight. The aluminum 10-spoke spare started showing up around 1985. In 89 GM started using PBR aluminum calipers and larger rotors on the rear, which resulted in the 10 spoke spare not clearing. They came up with a 15" aluminum inflatable spare to clear the larger brakes, they look like a normal steel inflatable spare, but they're aluminum under the black paint.

So, there are steel mini-spares, inflatable steel stow-away spares, inflatable 10-spoke cast aluminum stow-away spares, inflatable stamped aluminum stow-away spares...

To make things really fun, they also used two different size inflator cans in thirdgens. The label will specify the size tire the can will inflate. Then there are other larger cans for other GM vehicles. So two different inflators, three different sets of jack hardware, etc.

It's kind of common sense, but don't try to use a 30 year old spare tire that's been folded up all this time. Most people who have tried, haven't been able to find anyone that can refill the C02 canister.

Jbuchanan

That is very interesting, I have no desire what so ever to use that thing. Just thought it was cool it is all still there but then again my GTA spent 10+ years sitting in a field. Thank you for the education on it.

kimnach

Back in '90 or '91 I got a flat just a few miles from home, just on the entrance ramp to the highway. I jacked up the car, removed the wheel, put the spare on it, and hit it with the can to inflate. Well, the outer wall was stuck to itself within the fold. The tire inflated/bulged out over itself. No way I could separate the rubber. Took the thing off, called my dad (who was at work just a half mile away) and drove home to get the one wheel/tire that I saved from my '79 Berlinetta.

I haven't had a spare in my IROC since.

Ron U.S.M.C.

As was mentioned. I don't know about all LSDs but my Eaton Posi. (clutch pack) the rear tires don't only have to be the same diameter but over the long hall the same exact tire pressure or the unit will be damaged.

If some one is using the same diameter tire all around with a LSD and a flat in the rear. You can place the front tire on the rear and the smaller spare on the front.