I know the black diamond spoke wheels on my '88 Formula are different front to back. What I want to know is if anybody has a definative answer to the question: What are the offsets to the '88 black diamond spoke 15 inch wheels? If you could prove it that would be great, as I've found plenty of opinions I'd like to find these numbers somewhere in official literature.

On the Online Service Guide I've found the following: '88 black diamond spoke wheels are 15x6 with 37mm offset and 15x7 41mm offset front and back respectively.

http://floridafieros.org/osg/wheels.html

On the forum I've found the wheel offset diagram showing 15x6 42mm and 15x7 27mm front and back respectively.

https://www.fiero.nl/forum/Forum1/HTML/058236.html

So those are the numbers I've found, they are quite different and I'd like to find and verify the actual specs somewhere.

The rear 15x7s are identical to all other Fiero 15x7 wheels. The offset is, if i remember correctly, 30mm. The 37mm offset information is in error.

The front 15x6 wheels have a 42mm offset.
EDIT: This is incorrect; fronts are 37mm.

[This message has been edited by Steven Snyder (edited 01-22-2008).]

here you go

Again, I've already seen both of those specs along with Joe Torma's diagram. I even linked to it in my original post, what I'm looking for is PROOF be it in a service manual somewhere or a procedure that I can peform to measure the actual wheel itself. I don't want the same information recycled to me that I've already found in the forum. Even in these two replies we have the rears at 37mm and 27mm...

Thanks for the replies though hopefully we can nail down the real number.

[This message has been edited by Leeloo88 (edited 01-18-2008).]

https://www.fiero.nl/forum/A...031229-2-040757.html

Pretty well discussed to resolution in that thread.

JazzMan

So now I've got three conflicting opinions,

The Online Service guide which everybody seems to think is completely wrong:

Fronts 15x6 37mm
Rears 15x7 41mm

Joe Torma's Diagram:

Fronts 15x6 42mm
Rears 15x7 27mm

And finally Jazzman's thread where they seem to have agreed on:

Fronts 15x6 37mm
Rears 15x7 30mm

I think then we can all agree that 15x6 37mm is the true specification for the front wheels... sorry Joe.
The rears seem to be still up for debate, it seems that Joes diagram doesn't even believe the 86-87's are the same as the 88's but many folks in Jazzman's thread swear they are exactly the same. And the offsets range from 41 to 30 to 29 to 27.

BTW here's a nifty calculator for any aftermarket rims you may be looking to fit... all we need to do is find the correct baseline to compare to!

http://www.1010tires.com/WheelOffsetCalculator.asp

The Diamond wheels used on the 88 Formulas and GTs...

The '88 front wheels are 15 x 6 x 37mm
The '88 rear wheels are 15 x 7 x 30mm

Any source that tells you otherwise is wrong. Flat out wrong.

The Online Service Guide........ Is wrong.
Steven Snyder's belief that the 88 fronts have a 42mm offset........ Is wrong.
Joe Torma's diagram posted by 3.6lvvt6spdgt........ Is wrong.

quote Originally posted by Leeloo88:If you could prove it that would be great, as I've found plenty of opinions I'd like to find these numbers somewhere in official literature.

I don't have an opinion. I have measurements.

Official literature? Good luck. The amount of mis-information out there should be your clue that "official literature" hasn't turned up.

The only "proof" I can offer is that I measured them myself with my own skilled hands using equipment qualified to perform the task.

Your choices are:

a) Keep hunting for official literature.
b) Measure them yourself.
c) Believe me.

I recommend "b".

I'm assuming you already know what you're looking for here, but if not and you need help in the theory of how to take the necessary measurements, please let me know.

-Bruce at FTF Engineering

FTF is right. I remembered wrong in the post I made above. I've seen FTF's measurements from other sources as well.

And in my thread I measured several rims from several years and came up with the same numbers. It's been proven that all years of 15x7 lace wheels are the same at 30mm offset, and the '88 only 15x6 wheels are 37mm offset.

JazzMan