I'm really bothered with my GTA/GNX wheels.

G

GNVAIR

Member
Joined
May 24, 2001
Hey guys. I just installed the set of black GTA rims onto my GN about a week ago. They look wicked from the side, but I hate the way they look from the back. I am using the front offsets on the back with a P255/50R16 tire. They just seem like they sit too far into the wheel well which was the samething I disliked about the stock wheels. On these, there is like 2 inches between the wheel lip on the outside and like no room on the inside. I even went as far as installing the steel wheel spacers that drum brake GTA's and Iroc's use. It still didnt give me much clearance.
As for the front of the car; I have the b body spindles which increased the track width and as such, I installed the rear offsets on the front.
ok, so here is my wish........Does anyone make a GTA/GNX rim with 4 inches of backspacing? Anyone? Anyone?
 
I measured the b.s. on my GTA wheels and it is 4 3/8" as I recall...4" would be about perfect but 3/8" does not make much difference to the eye, I don't think.

My Nittos are mounted on 8" wheels with 4" b.s. and that is just about perfect on my car for centering the tire in the hole...
 
Many people do not know this but from the factory the GNX used 4 "front" GTA style wheels. Maybe this would help if you have 2 fronts and 2 rears. Just a thought Good Luck! Do you have any pictures of them on the car that you could send me? Thanks again!
 
Actually, the GNX didn't use GTA front wheels at all. GTA fronts are "zero offset.

GNX wheels were offset out more than 1/2 inch in front and and about a full inch in back (approximately 3.5" backspacing in back)

That why GNX's have flairs.

I had a big idea a few years ago to buy weld on 9" style C-clip eliminators, but special order axles that were .75" longer. Then make the track 1.5" wider. My plan was to widen a pair of stock T type wheels by an inch on the inside.

I don't know if this would work and I didn't pursue it any further (like a lot of ideas I come up with)
 
UNGN is correct. A friend of mine had a set of real GNX wheels that were on a GN he bought. They appear physically identical to the GTA wheels, but the offsets are different. Yes, they have a "front" and "rear" specific positioning. If I remember correctly,the backspacing on my GTA wheels measured 5" for the "rear" offset and 4 1/2" for the "front"
The GNX's were I believe 4" front and 3.5" for the rear. I think I might start looking into having a custom offset made.
 
If you want some serious wheel spacers write him.
I have a set of his 1.25 I'm going to use on the rear of my GN.
I'm serious thinking about using his 2"ers on the front (I too have B spindles, and running TA rears on the front for now).

skulte@skulte.com
 
I can get CNCed wheel adapters as well. Name your thickness, diameter etc...

Let me know if i can help! - Evan

I am a wholesaler for wheel adapters. I really stopped selling them because it became a hassle :(
 
If you have front TTAs on the rear of your car, the BS is over 4" as noted by Steve Wood. I have IROC fronts on the rear of my car which have the same BS as TTAs. I removed my 255s and installed 295 50 16s on them which are 10 1/2" wide. I had to use a 7/16" spacer available anywhere. They fill up the whole wheel well and have the appearance I think your looking for. Easier and cheaper to get tires than find or modify rims.;)
 
I just question the safety of running the slip on style wheel spacers since the GTA rims are hubcentric and depend on the protrusion of the hub through the center of the wheel. Right now as it is with the steel GM wheel spacers, the lugs are what are actually centering the wheel.
I have seen the thick aluminum wheel spacers some guys run to use the 93-up F body and 84-up Corvette offsets. These seem safer since they actually bolt on like a wheel and have their own set of studs to bolt the wheel onto.
 
I have 4 "front" GTA rims on my GN and I too feel they "suck in" a little much in the rear. Part of this could be because of aluminum drums. Also, my front tires appear a little wider than the rear 245/50R16 Nittos, even though the front tires are also 245/50s. It bothers the hell out of me, but what can you do?
 
All you could do is buy different wheels or use spacers. While some folks are worried about spacers, I think they are safe if you have long enough lug studs. I think that's where people have problems. Mine are 2" long. By the way, I also have aluminum brake drums.
 
Would you be afraid to road race or autocross with the spacers? Arent the aluminum drums thicker?
 
To be honest, I don't do road racing or autocross but I feel the studs are strong enough to take that stress. Just as long as the lugnuts have enough threads. Forget about slip on spacers with stock length lug studs. Oh and yes, aluminum drums are thicker than steel drums.

This has actually changed the subject. How do you feel about that bigger tire to eliminate your appearance problem?
 
Well, since my 255's are brand new, I would be opposed to it now. But maybe later on.
I am going to look into the spacers that Bruce mentioned.
 
Please post or e-me when you figure something out I'm dealing with the same thing right now, I was thinking long wheel studs with 1/2 spacer but don't want the wheels flying off I beat on this car everyday and go to the track almost every weekend so I need it reliable.
Thanks
 
Now I'm confused.

I’ve got a new set of CI GTAs out in the garage. This offset/backspacing discussion has got me all confused. Factory GNX wheels had positive 16mm (about .59in) offsets in the front and positive 23mm (about .91in) in the back. (The GTAs from CI are zero offset) A positive offset actually sinks the wheel into the well when compared to a zero offset (a negative offset would push it out). I’m not sure, but the GNX wheels and the GTA wheels are probably about the same width? Anyway, backspacing is equal to half the width plus the offset (for positive offsets), therefore the GNX wheels would have greater backspacing (unless my assumption about wheel width is wrong). I measured my GTAs and their backspacing is around 4 3/8 depending on how you measure (don’t think you’re supposed to go all the way to the edge of the rim). Thought I saw someone say that the positive GNX offsets are why the GNX had fender flares. I could see why a wider wheel might require flares, but positive offsets actually reduce the overall track width. Strange. Anyway, time for a cold one. Comments welcome.

Matt
 
Bad info on gnttype.org?

Hmmm. I was taking gnttype.org at face value:

Both styles were 15"x7". '86/'87 GN wheels had a 3mm negative offset and 4" of rear backspacing. The aluminum wheels had 3 3/4" of rear backspacing. The circle bolt pattern was 5 X 4 3/4 inches.

The GNXs came with P245/50VR16 Goodyear Gatorbacks on the front and P255/50VR16 on the rear. They were black letter, NOT all-season, and mounted on 16'x8" modular style wheels with a black center section and polished rims. The front had a 15mm positive offset and the rear, a 23mm positive.

...so the GNX wheels were actually negative offsets - at least that would make sense with the flares.

Matt
 
Yeah. GNttype have the meaning of positive and negative offset reversed. It's been that way for 6 or seven years. It's like one of those stamps with upside down mailplane on them. The errors give the site character.
 
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