I've got a 1985 IROC and the other day I pulled all the wheels off just to clean and polish. Then I noticed a small (1/4 inch) wheel spacer on both sides of the rear axle. Is this a factory thing or did someone along the way decide they wanted a different offset in the rear?
dagwood
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Quote:
Those are factory on drum rear brake carsOriginally Posted by MichiganWildcat
I've got a 1985 IROC and the other day I pulled all the wheels off just to clean and polish. Then I noticed a small (1/4 inch) wheel spacer on both sides of the rear axle. Is this a factory thing or did someone along the way decide they wanted a different offset in the rear? 
JamesC
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Apr 15, 2026
Why Does My Rear Have Spacers?
The spacer was apparently used on 16" wheels when GM switched from aluminum to iron drums, which created a .187 size difference. The spacer, however, seems to be hit or miss and essentially unnecessary. Even some disc brake cars received them. Mine did.
JamesC
The spacer was apparently used on 16" wheels when GM switched from aluminum to iron drums, which created a .187 size difference. The spacer, however, seems to be hit or miss and essentially unnecessary. Even some disc brake cars received them. Mine did.
JamesC
Mine is 4 wheel disc
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Iirc, it has "GM" stamped on it if its factory.