Abysmal tire options...
 

Swiped from another thread:
Sooo true, in terms of tire options. Have no interest in A/S tires (live in FL) and prefer a softer, "summer" compound--but not a drag or track-only tire. BFG stopped making the Comp II Sport (at least in either 245 & 255 16s), and the only decent option I can find is the General G-Max RS. As time goes by, I'm sure it will only get tougher finding OE-size options other than drags & A/S.

So I started looking at 17s--as Jake suggests. The 275/40zr17 has lots more options, but of course requires diff wheels. I looked at the stickys here, but the wheel options are all years old, and you can't put just anything on a 93 - 96. The bolt & offset is distinctly Chevy (4.75 & 6.875), and there's also some concern w/ the rear hub diameter (70.75mm). I'd like to avoid using adapters. I'd also want to unisize (same size front & back).

The problem I'm finding is that retailers rarely know what they have, and seem to think 'a wheel is a wheel is a wheel...' Most have no clue about bolt circles, offsets, etc. I keep hearing, "it should fit..." Riiiight.

Ergo, can anyone provide some current options that will fit on the 93 - 96 w/o adapters? Any links to the specs? I prob will get the G-Max RSs for now, but don't expect to get much more than ~20K on them. In the meantime, I can get some diff wheels and plan to move up to 17".

Re: Abysmal tire options...
 

You will want 17 x 9.5" with an offset in the range of 49-56mm. 6.875 is the backspace (not offset) of the stock 8" wide wheels. Not something you need to match. You can run a 7.75: backspace in the back with no problems, and 7.95" with minor tweak, although that is only necessary with 10.5" or 11.0" wide wheels. In the front, you need to run 7.50" or less. backspace.

If you find a wheel with questionable dimensions, post a link and I can do the math.

The 4.75" bolt circle converts to 120.65mm. Some people opt for 120.0mm bolt circle, but I don't recommend it.

If you get a wheel with the smaller hub center bore, a light sanding of the bore will allow them to fit on the 93-96 rear ale.

I've seen lot of options on Hawk's Motorsports. I have no idea on how their prices or customer service is. Just suggesting a place to look at options.

https://www.hawksmotorsports.com/93-...wheels-brakes/

Re: Abysmal tire options...
 

I’d recommend looking at OEM/stock wheels from any fourth-gen SS, WS6, or Firehawk. You know they’ll fit, and they’re higher quality than everything aftermarket until you get really pricey.

Re: Abysmal tire options...
 

I found a conversion chart, and on Hawks--one of the few sites that provides specs for certain wheels--they have the 93 - 02 10-spoke 17x9, 4.75 bolt, 12/5.5 offset/backspace. They don't list the hub diameter; since they're made for the 93 - 02, I assume they would work, but I read that after 96, the rear hub went to 70.5. Kinda pricey @ $1200.

They also have the C6 5-spoke Vette wheels that are 17x9.5, 120.65 (4.75), 54/7.38 & a hub that's a tad small @ 70.3. These are a bit more reasonable @ $863. Both of these appear to be OE--as Jake suggests. Much of the other stuff they have has diff front & rear, which would virtually elim. rotating.

I also checked out TireRack, and they have the AR VN515 Torq-Thrust II (similar to what others in here have noted) 17x9.5, 4.75, 46/6.97 (hub not listed). These come in @ $968. After the ARs, the cost gets crazy.

It looks like whatever I get, I'd need to mod at least the rear hub, and maybe both. As I understand it, the 93 - 96 Z has a 70.5 front & 70.75 rear. It doesn't seem like much of a mod, but since I've never done it, does it need to be perfectly true? Or can you eyeball it, as long as it fits over the hub? I have a small air grinder that I could use to follow the circle. Hawks goes into some detail on the chroming process, but would modding the diameter result in flaking? Or does it even matter, since it's covered by a cap?

The 93 - 96 Z gets no love...

Re: Abysmal tire options...
 

That 17x9.0” 12mm wheel would put the outer edge of the tire about 1/2” outside the rear fender.

Corvette wheels typically have a 70.3mm bore:

I have seen a variety of numbers for the 93-96 front and rear hubs. Way back I posted all 4 wheels on my 94 measured 74.1mm. I can’t remember if I actually measured that. But is doesn’t matter. Just accept the rear axle hub is larger than the front.

First, that confirms that GM decided to use “lug centric” wheels, rathe than “hub centric”. That's the only way you could have 2 different axle hubs, but run all 4 wheels with the same size (larger) bore.

Second, consider how small the difference is. The 0.25 difference you cite, and this site calls out - see very last note at bottom:

Firebird and Trans Am Wheels

…. converts to an 0.01”. I have seen differences as large as 3.8mm in print (in fact I quoted that maybe 15 years age). That is a difference of 0.03”…. three hundredths of an inch. Easy to remove with an abrasive cloth/paper or Dremel, keeping it neat and somewhat circular. The key here is to insure the wheel bore is greater than the hub diameter, to the extent 1) the wheel will easily fit over the hub without hitting it or binding, 2) the clearance allows the wheel to be centered by the conical lug nuts.

I've seen people asking this question for 20+ years, and have never seen anyone who managed to screw it up, or who came back indicating “the rear of my car is vibrating since I screwed around with those wheel bores”.

I don't know about damage to the chrome.

Do you not like the Corvette ZR1/Grand Sport replicas? I run a staggered set, from AFS, bought about 20 years ago. The are clearly marked “made in USA”, cast in to the back of the spoke.

Re: Abysmal tire options...
 

I wondered 'bout that, since all the others are 45+. I don't want anything that could potentially get clipped by the fender.
As I noted, I realize a diff of .25 doesn't seem like much, but I'd hate to lay out ~$1000 for a set of wheels and then botch the job. Still, that no one is grousing 'bout it is a good sign.

I do have a fine-grind attachment for my mini-grinder that would ostensibly limit the potential for flaking/peeling, esp. if the process uses a copper substrate, as Hawks notes.
I haven't seen those, at least not on any of the sites where I've been looking. So far, I've been focused on viable specs & what they actually have--in stock--that meets those specs. As I noted initially, many retailers don't know the specs.

Re: Abysmal tire options...
 

A lot of people dislike the ZR1/Grand Sport replicas because they are "too common" and "boring". I've had mine for 20 years and wouldn't put anything else on the car for the street. There are several versions of the wheels - painted, polished (mine), deep-dish (wider outer lip), etc. To me, the newer replicas seem to have a slightly less rounded edge to the spokes.

There are 17 x 9.5" 56mm w/ 275/40-17 in the front, and 17 x 11.0" 50mm, w/ 315/35-17 in the back, If you went with the 17 x 9.5" all the way around, the outer edge of the tire would be about 1" deeper in the fender well in the back, compared to the 11.0" wide wheels.

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https://cimg9.ibsrv.net/gimg/www.cam...1b6a8588f0.jpg

https://cimg1.ibsrv.net/gimg/www.cam...a87aaf36e3.jpg

https://cimg3.ibsrv.net/gimg/www.cam...07cea9a0f5.jpg

https://cimg6.ibsrv.net/gimg/www.cam...8a47e4e350.jpg

Re: Abysmal tire options...
 

Dunno 'bout them being common or boring; heck, I like the stock wheels, and if not for the difficulty in finding tires, wouldn't change them. You've got the C4s; they look fine on yours--even got a Pontiac cap. Found 'em on Stock Wheel Solutions for ~$825, w/ shipping.

I like the 10-spoke Z06 C5s, but no one seems to have 'em--imagine that. I did find the 10-spoke C6 for about the same $$ as the ARs. SWS does have quite a few options in 17s. I saw in another post where BandDir was relating his exper. w/ diff sizes (17, 18 & 19), w/ the upshot that the 17s provided the best ride quality, relative to the stock 16s. While other aspects figure into it, I'm inclined to stick w/ 17s.

For the time being, I can hurry up & wait for the G-Max RSs. Sigh...

Re: Abysmal tire options...
 

The wheels originally came with plastic Corvette emblems glued on the center caps. Brent Franker made the silver disc decals with the Pontiac arrowhead for me.

Re: Abysmal tire options...
 

Those wheels look really good on your car, Injuneer. I've gotta get some new wheels and tires. I don't get to drive my car very much, but I'm still running the stock salad shooters on my '94 Z-28 and the tires, which are in surprisingly good shape, are at least 21+ years old. Wheels are quite the difficult decision.

Re: Abysmal tire options...
 

Re: Abysmal tire options...
 

I definitely need new rubber and had planned to do that as part of a new wheel purchase. Based upon the tread on the tires, I'm guessing they were fairly new when I parked the car in 2000, but they're still approaching, at minimum, their 21st birthday, which is well beyond what tire manufacturers seem to consider end of life. I've put about 1000 miles on the car since I started driving it again in late 2017, and those have been very conservatively driven on isolated country roads around my hometown in southern Ky.. It might be smart to get some new tires for the salad shooters even if I plan to replace them in the not so distant future, but consistent with the spirit of this thread the choices do seem limited. I guess anything would be better/safer than the tires on it right now and I really have no idea what I'm going to do in regards to new wheels/tires, or when.

Re: Abysmal tire options...
 

x2 on that. You don't say how the car was stored all that time, but at the least, you'd need to get them balanced--preferably speed balanced--and no decent shop will touch tires that old. Mine are...ok...as long as I don't get above ~50mph, but...

You can still get tires, as long as you want either drags or AS. There are actually a number of AS options, but they don't have the same grip as softer compounds. It's a no-brainer for me, since I live in FL, but dunno 'bout KY, or what your plans for the car are. The only decent soft tire I could find was the G-Max RS. Which takes roughly a month to get.

Re: Abysmal tire options...
 

It wasn't prepped for storage, but it was garaged and for several years it was on jack stands. I'm the original owner and at one point the car was my daily driver, but now it's just something to tinker with and drive for fun. I can't really say that I have plans for the car, but I'm not a drag racer or anything.

Have the BFGoodrich - g-Force Sport COMP-2's definitely been discontinued in the 245 & 255 sizes? Most sites are showing out of stock or backordered, but there is a review on Discount Tire's site for a 95 Z28 from July of this year.

At some point I plan to get "new" wheels and tires, but I have no idea what I'm going to get or when. If I could get a decent tire for the stock wheels, I might be content to just leave them on the car.

Re: Abysmal tire options...
 

Sounds like you're in the same boat w/ me. Garaging helps limit dry-rot, and since you had it on stands, you likely avoided flat spots. Still, no reputable tire shop will touch 'em, so plan on new tires. I like to tear up freeways--esp. down in 'gator alley'--so the softer tire is the only real option; using AS is like feeding it 87 octane. Not sure what kind of driving you plan to do, but it sounds like you might want the softer tire.

BFG told us they had "no plans at this time" to make the Comp II Sport in 245 or 255 16. There might be a few stragglers around, but good luck finding a full set. The 275/40ZR17 is in stock @ TireRack. Starting w/ the late 90s, fewer cars use 16" UHP tires. Not enough to compel production @ BFG.

The G-Max RS is alleged to be a good UHP tire--why I decided to get a set--but dunno how long they'll continue to make 'em in that size. It's gonna be end of Oct. before I actually have them, not a good sign. You might want to give 'em a try. But many more options @ 17", so I'll be ready for the change when these wear out.