Stock Tire Size

[jman093]

I need some new tires for my 96 GTP. When I bought the car the tires were fairly worn and you could tell the sidewall had gone soft as peanut butter, but after a few weeks of daily driving they've gotten bulges in them. I think the beefy suspension has taken it's toll. Right now the tires on it are 205 55's. No way that's the right size. I don't see a GTP having skinnier tires than my old Euro Lumina which had 215's.

 

Problem is I can't find the stock size. There's nothing on the door or anything, and the Parts Dept. at work doesn't have that info, so they say. I checked on Tirerack.com and they don't list a 96 GTP. I also looked on Goodyear and Michelin's websites and they both say OE tires are 245/50ZR16. That seems way to big to me. Hell, that's what a 4th gen Z28 Camaro was equipped with! If that is what it was equipped with, awesome. I'd love to get some meats on it, but I figure I'll check here before I buy expensive tires I'm never going to get mounted on my rims.

 

Oh, my GTP has the Special Edition 5 spokes, if that makes a difference.

 

Thanks, Jesse

[jeremy]

with the 5 spokes your stock size should be 225/60/16

[Andrew]

with the 5 spokes your stock size should be 225/60/16

yes.

 

you can run a 245/55/16 but not many tires are made in that size.

[BIGBULS]

with the 5 spokes your stock size should be 225/60/16

 

Correct.

 

 

 

And the tire/loading sticker is under the trunklid. GM got dumb with the W cars.........every other car has it on the door/doorjam.........just not W Body's.

 

 

 

 

Oh, and 30psi cold tire pressure too

[Breakdown]

The tire size is in the trunk.

 

Under the spoiler.

 

I will also confirm a 225/60R16.

 

Distributors will simply take the first year of a body style and trim and apply it to all of the cars until they changeover. So 1991-1996 GTP is assumed to all be the same. I believe that GM switched in '94 or '95 to the 225's from the 245's. The 245's fill out the wheelwell much better. So those flares have a look of, if they weren't there the wheels might look like they're sticking out a little.

 

I put 245/16ZR45's on mine. Looks better, lowers the car about 1/2" (.9 inch loss in diameter) and throws the speedo out approx. 3.5% (when you are going 103.5 MPH, you are actually going 100.

 

With an S/E, and 5-spokes, I think that you have 7" wide rims, which means that you could accomodate 245's, depends how performance oriented you are. Also how much you want to spend, for any 245's it's going to run you an extra 30% minimum over the 225/60R16's. Unless you can find a good used set.

 

Best of luck.

[jerry455]

the 89-90 turbo grand prix is the only w body that had the 245-50 zr 16 tires. 225 60 16 was stock on most other cars.

[CSI_MuNkY]

the 89-90 turbo grand prix is the only w body that had the 245-50 zr 16 tires. 225 60 16 was stock on most other cars.

 

That is not true... ALL GPs I have seen pre 94 had 245's stock, They switched to 225 in 1994 along with the change in the body kit.

 

Jamie

[jman093]

Sweet thanks guys. Ya, if my sticker is underneath the trunklid then it's never to be seen again. There a big piece of material underneath the lid with "GTP" emroidered on it there.

 

Well since 245's can be fit on my rims that's what I'm going to get. Probably stick with the 50 series and not the 45's though. The car's only got about 4 inches of ground clearance as is. The stance is bitchin' right now, don't want to change it.

 

 

[3.1cutlass]

Sweet thanks guys. Ya, if my sticker is underneath the trunklid then it's never to be seen again. There a big piece of material underneath the lid with "GTP" emroidered on it there.

 

Well since 245's can be fit on my rims that's what I'm going to get. Probably stick with the 50 series and not the 45's though. The car's only got about 4 inches of ground clearance as is. The stance is bitchin' right now, don't want to change it.

 

 

I would not run a 245 on a 7'' wide rim. Thats a 9 inch wide tire.

[Breakdown]

Sweet thanks guys. Ya, if my sticker is underneath the trunklid then it's never to be seen again. There a big piece of material underneath the lid with "GTP" emroidered on it there.

 

Well since 245's can be fit on my rims that's what I'm going to get. Probably stick with the 50 series and not the 45's though. The car's only got about 4 inches of ground clearance as is. The stance is bitchin' right now, don't want to change it.

 

 

I would not run a 245 on a 7'' wide rim. Thats a 9 inch wide tire.

 

If you can do a 225 on a 6.5" rim, 245 couldn't be that bad, I've seen 245's on the 6.5". Personally, I would not recommend it, as stated earlier, just for cost reasons alone, forget about ride.

 

 

[CSI_MuNkY]

Just find a nice set of cross laces... 8 inches wide FTW!!

 

Jamie

[jerry455]

just because the tire stores say so ,it isn't always true. I work for gm at the gm tech center in warren mich. I am a pontiac fan and when we would get our fleet of test vehicles there was always a few grand prixs. I have been around them since 1986, the only w cars that had 245's were the turbo gand prix's. look under the deck lid of these cars and it will tell the stock size. the grand prix's look great with the wider tires but all the other B4U option cars only had 225 60 r 16 tires. when we had the turbo cars new it was not uncommon for the tires to rub on the fender flares when turning. there was bulletins from asc covering the adjustments to stop the rub. i really like the tgp as it is a fun car to drive, i have had this one since 1999.

[LuminaPower92]

Just find a nice set of cross laces... 8 inches wide FTW!!

 

Jamie

Want to find a set for my Lumi, black ones, Ahem Aweb!!!!

[BXX]

Like 3.1cutlass said, DO NOT run a 245 tire on a 7" wide rim... The minimum is 7.5" up to 9.5" wide depending on the aspect ratio.

 

I do believe to put a 245 on a 7.5" rim safely, it must be a 245/55/16.

 

Not only will it be a bitch to seat the beads properly with a 245/45/16 on a 7" rim, you will have highly increased edge wear, it will upset the handling especially in wet conditions, and loss of pressure will easily cause the tire bead to pop off the safety ridges on the rim.

 

Just go by the stock size. P225/60R16 97S rated

[Breakdown]

just because the tire stores say so ,it isn't always true. I work for gm at the gm tech center in warren mich. I am a pontiac fan and when we would get our fleet of test vehicles there was always a few grand prixs. I have been around them since 1986, the only w cars that had 245's were the turbo gand prix's. look under the deck lid of these cars and it will tell the stock size. the grand prix's look great with the wider tires but all the other B4U option cars only had 225 60 r 16 tires. when we had the turbo cars new it was not uncommon for the tires to rub on the fender flares when turning. there was bulletins from asc covering the adjustments to stop the rub. i really like the tgp as it is a fun car to drive, i have had this one since 1999.

 

My 1991 Pontiac Catalogue lists the 245's as the GTP's tires - at least I'm 90% sure it does, I'll have to double-check.

[jeremy]

here is a link to the '93 Grand Prix Brochure that AWeb posted in another thread....245 width tires were available

 

http://www.w-body.com/forum/index.php?action=dlattach;topic=69988.0;attach=10740

[Breakdown]

here is a link to the '93 Grand Prix Brochure that AWeb posted in another thread....245 width tires were available

 

http://www.w-body.com/forum/index.php?action=dlattach;topic=69988.0;attach=10740

 

Thank-you!

 

Now, I don't have to find mine (yet), it's in a box around here somewhere!

[CSI_MuNkY]

just because the tire stores say so ,it isn't always true. I work for gm at the gm tech center in warren mich. I am a pontiac fan and when we would get our fleet of test vehicles there was always a few grand prixs. I have been around them since 1986, the only w cars that had 245's were the turbo gand prix's. look under the deck lid of these cars and it will tell the stock size. the grand prix's look great with the wider tires but all the other B4U option cars only had 225 60 r 16 tires. when we had the turbo cars new it was not uncommon for the tires to rub on the fender flares when turning. there was bulletins from asc covering the adjustments to stop the rub. i really like the tgp as it is a fun car to drive, i have had this one since 1999.

 

My 1991 Pontiac Catalogue lists the 245's as the GTP's tires - at least I'm 90% sure it does, I'll have to double-check.

 

x2, I don't care if you've been a Pontiac tech since 86, your still wrong. I have seen the trunk sticker on Q-balls 92 GTP, 245 tires are listed. Not to mention countless stickers at the wreckers. I do believe that any tire on a cross lace rim (that I have seen) leading up to 94 was a 245, as I have yet to see different. Now if they got the 15" rims or the 5-spokes, that I can not vouch for (I don't pay attention to the rims with less than an 8" width, lol)

 

Jamie

[BIGBULS]

I'll throw this in:

 

MY car (a B4U car with 16 X 8in crosslaces) had 225/60R16 Goodyear Eagle GT+4's stock (with an oddball "U" speed rating..........a pair of which were still ON the car when *I* bought it back in 1996).

 

BUT.

 

I have ALSO seen 245/50R16's spec'ed for some GTP's with crosslaces. For verification, I can also point to the 20 May 1991 Grand Prix GTP test in Autoweek magazine..........THEIR test car had 245/50's as well.

[BIGBULS]

BTW..........one thing I DO know is that ALL of the 245/50R16 cars I have seen had Goodyear Eagle ZR's (Gatorbacks)..........full-on summer tires. I *think* it was a GTP (only) option, and ONLY for 91-93 manual trannied cars.

[jerry455]

just saying that i had never seen them on any other w body especially after all the tire rubbing problems when the turbo cars came out in 1989. all of the gtp's we ever worked on had 225's and they had the cross lace rims.

[jman093]

Lol, Look at what I started. Anyways, I don't think whether 245's came stock is important, just whether or not any of us can run 245's, and it looks like just the 16x8" crosslace wheels can use them. I've decided I want some high end performance tires, which sucks for me and my 7" Spec Ed 5 spokes, because no good tires come in that 225/60R16 size. Maybe the Michelin Pilot Sports, but even that's not really what I want. To get a good handling tire in 16" size you have to get the 245/50ZR16 size it because opens up all options including the new Eagle F1's.

[Andrew]

Hal always ran 245's on my Z34 and never had a problem. its whats on there now too.

[Breakdown]

Lol, Look at what I started. Anyways, I don't think whether 245's came stock is important, just whether or not any of us can run 245's, and it looks like just the 16x8" crosslace wheels can use them. I've decided I want some high end performance tires, which sucks for me and my 7" Spec Ed 5 spokes, because no good tires come in that 225/60R16 size. Maybe the Michelin Pilot Sports, but even that's not really what I want. To get a good handling tire in 16" size you have to get the 245/50ZR16 size it because opens up all options including the new Eagle F1's.

 

I've seen as big as 255 on the Special Edition rims (the 5-spoke 1st Gen FWD rims), but go to a good tire shop and ask the questions, I think it might be a case of the performance 245's being such a poor fit that they comprimise any handling advantages that you might get by having those expensive tires.

 

But, to be 100% honest, if you're going to be that keen on performance of the tires, just get a set of X-laces. You can't always have the look you want and performance.

[CSI_MuNkY]

But, to be 100% honest, if you're going to be that keen on performance of the tires, just get a set of X-laces. You can't always have the look you want and performance.

 

x2

 

Go to your local wreckers and see about getting a set of cross laces, you won't regret it. I have a set of 255s on cross laces, so going up to the 8" wide rim opens up a whole lot of options. (the 255s rub like crazy, just so you know)

 

Jamie