Sorry guys to post this here but I got no response in Suspension / Chassis / Brakes. Here's the question:
I know that on my T/A w/16" mesh style wheels the backspacing is suppose to be 0mm on front and 16mm on back. But by looking at the wheels how can I tell which ones are which? I had new tires put on my car and I think they got them switched backwards. Just by looking at the wheels the ones on the front are deeper than the back is this right? I'm also getting some rubbing in the rear passenger side and front.

------------------
'87 Trans Am:
(Engine)
305 TPI
160 Degree Thermostat
TB Bypass
Accel 300+ 8.8 Racing Wires
Accel Super Coil
Bosch Platinium Plugs
Custom Ram Air with K&N
Removed Emissions Equipment
(Stereo)
Kenwood Excelon

 

If your wheels are like the 16" IROC and RS wheels then the wheels with the deepest back side(looking at the back of the wheel) goes on the rear of your car. Your wheels should be labeled front and rear as well.

Steve

 

You're talking about offset, not backspacing. There's a thread somewhere on here that has a really good diagram of the wheel terminology. Search the archives for it, and I'm sure it will have the answer to your question.

 

I searched the posts and I have only found that they are labled front and rear on the outside. But where at? Can some just look at their wheels for me? All I can tell is that the rear ones aren't as deep as the front ones. There is about 1/2" differance between them. They are the factory GTA style 16x8's. Surley someone knows off hand or could look.

------------------
'87 Trans Am:
(Engine)
305 TPI
160 Degree Thermostat
TB Bypass
Accel 300+ 8.8 Racing Wires
Accel Super Coil
Bosch Platinium Plugs
Custom Ram Air with K&N
Removed Emissions Equipment
(Stereo)
Kenwood Excelon

 

JRyan,

If you are talking about the Crosslaced wheels, they are marked on the inside face of the cast center basket.



These are not "GTA style" wheels, since they were available on TAs back when "GTA" meant Grand Theft, Auto. This was before the GTA was only the wet dream of some lard-butt marketer at GM who didn't like the bumpity ride and austere nature of the TAs. (To me, form follows function, but I'm kinda old-school.)

The Crosslaced wheels, viewed from the outside, have a 3-1/4" depth from the wheel rim to the edge of the cast basket, while the rear wheel has a 2-3/4" space from the rim to the basket.

Hope that helps.

Incidentally, if they screwed that up, are you sure the tires are installed correctly? Many of these tires are directional, and are intended to be installed with a preferred rotation direction to prevent carcass overheating and delamination (remember the Firestone situation?)

Also, ask them to rebalance your tires. Mounting them on the wrong end of the car can cause the wheel weights to scrub on the tie rod ends, removing some of the heavy metal from the weights and changing the balance, or actually moving the weights or completely knocking them off the wheel.

------------------
Later,
Vader
------------------
"I'm'a do Things My Way - It's My way or the Highway."
Adobe Acrobat Reader

 

Thanks guys for the help.

------------------
'87 Trans Am:
(Engine)
305 TPI
160 Degree Thermostat
TB Bypass
Accel 300+ 8.8 Racing Wires
Accel Super Coil
Bosch Platinium Plugs
Custom Ram Air with K&N
Removed Emissions Equipment
(Stereo)
Kenwood Excelon

 

Hey jobryan26,

You're correct about the offset for the rears being 16mm. The fronts are 0 offset which provides the best handling characteristics for our cars. The polished inner lip gives away the fronts because they are truly deeper than the rears (about 1/2").

If the rears are mistakenly mounted on the front you risk damaging your wheels and the tie rod ends like Vader said (as I have experienced earlier thanks to some idiot at Mr. T***, when I did'nt know better).

Anyway, on the T/A crosslaced wheels as well as on 3rd gen Formulas, the wider lip tells you that it's a front wheel. Just make sure the guy mounting your wheels knows this! Good luck.

nFORM91



------------------
Proud newly acquired '91 Formula 305 TPI 700R4, 34.5K documented miles, fresh Flowmaster catback w/chrome tips, Factory black on black all stock - no current engine mods (might keep that way!). Rims are '91 T/A black Diamond Spoke 16x8s. 20% tint & Black Widow Alarm system. future plans: fresh paint job, new 255ZRs all around.