Are the factory 16x8's rear IROC wheels the same backspacing whether you have disc or drum brakes? I'm looking to upgrade the 15x7's on my 84 Z28. Will any year fit?

Thanks in advance.

 

I'm 99% sure that all 16" Iroc wheels are the same, regardless of year.

 

Yep, they're the same between disc or drum brakes. Just remember the fronts are different backspacing than the rears

 

Yes and Yes. Just to clarify, ALL REAR IROC wheels are the same, regardless of year, and type of brakes. ALL FRONT IROC wheels are the same. ..but the fronts and rears are different. Fronts have a 0mm offset. Rears have a +16mm offset.

 

If you don't have aluminum drums, you'll probably want to track down a set of stock spacers if you want to do the job right. But it doesn't really matter, they'll fit without the spacers, but GM used them...

 

Did ALL drum cars with IROC 16" wheels get factory wheel spacers in the back, Or was that JUST with factory Aluminum drums ?? I always believed it was JUST Aluminum drum brake cars because EVERY set of spacers I've ever had shows the same "pattern" or "imprint" on the side that touches to the drum. This pattern exactly matches the Aluminum drum face / mating surface & this pattern I'm describing is not present on the flat-face of a steel drum.




I've had dozens of sets of those spacers and they ALL had that pattern on them, That's why I always believed the spacer was for ALUMINUM Drum + 16" IROC configuration.

 

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

 

I have rear drums (aluminum) but don’t have spacers and they fit fine but n my 84. You won’t have any issues.