tire sizes

[greg wilson]

hello im a new member and a new proud owner of mint 87 gn im also the proud owner of a 00 C5 vette i love both of these cars i have 2 of the badest american muscle cars of all time in my book . im ready to start modifying the gn but the 1st thing is tires i have puny 215 15s in rear what is the largest tire, i can put on a stock rim thanks.

 

[qwic87gn]

A 275-50 will fit the stock wheel. Some say its unsafe but I have ran that size for 3 years with no problem whatsoever. It gives it that desirable NASTY look.
Good luck.

 

[gndriver]

Well i got 295- 50 15 with a 3mm spacer on. And I went from shredding my 275-50's to only chirping second and third now.

 

[GrndNatnl]

How tall are the 275/50's? And the 295's? I'm looking for rear tires too. I want decently fat, with a nice meaty look to the rear, but I dont want them -too- tall, to where I change the gear ratio too much.

 

[UNGN]

275/50's are the stock height: 26" (Nitto 275/50's are a little shorter (25.7), but thats Nitto)

With GN Wheels, you will need to run a small spacer and or aluminum drums to be happy with 275/50's out back, otherwhise they will rub the frame in hard cornering.

For the street, 255/60's are a good non drag radial size for the back. They are slightly taller than stock and will throw off the speedo about 5%, but TR's like a taller tire and the speedo error is a small down side compared to the benifits of a taller tire.

If you want to run the same size tire all around, 235/60 would be the biggest you would want to go on GN wheels.

 

[gnturbo]

I am running bfg's all the way around-235/60's front-275/60's in the rear,but I am runninf 4 1/2 " backspaced weld wheels.I believe the stockers are 4" BS aren't they?I still rub on hard cornering .I already have aluminum drums,Is it safe to run a 1/4" spacer to get it off the frame a little?anybody,anybody?

 

[GrndNatnl]

What series 255's could I run to keep the speedo correct. 255/55's?

 

[UNGN]

Originally posted by GrndNatnl
What series 255's could I run to keep the speedo correct. 255/55's?

255/50R16's are a perfect stock height, but won't fit for obvious reasons.

It would be tough to find 255/55's in a 15" wheels size.

245/60's are widely available and are closer to the stock height.

 

[BoostedBug]

I run 245/50/16 on front and 255/50/16 on the rear on a set of the gnx rims from kirbans. Also I have the Hotchkis 1.5"lower springs, bilstiens , swaybar by ATR, brase kits and on and on.

 

[GrndNatnl]

Ok, here's a question that'll make things plain and simple:

What is the fattest 15 inch tire I can put on the rear, that is stock height & wont throw my speedometer out of whack? And that wont really rub, or at least maybe juuuuuust barely if a hard corner is encountered? But preferably no rubbing. I'll be getting new rims for it eventually (probably Telstars), but I need new rear tires sooner then that, and going to have them on stock GN rims for a while.

That's the answer I'm really searching for. I hate having to worry about height / gear ratio / speedo accuracy. So I want to get it right. I wanna go with BFG Radial T/A's.

 

[J Banning]

I know several people that run/have run 275/50/15's on a stock GN rear wheel. They should be stock height, and they work very well. I would not go with any smaller of a tire on this car.

To the best of my knowledge, a 295/50 will NOT work on a stock rim. If you did manage to fit it, I would imagine that the contact patch would be poor as would the tread life.

I run a 295/50/15 on a 15x8" wheel. I know two other guys that run the same. They have zero problems, however my axle isn't quite centered in the vehicle so I have to run a small wheel spacer on the drivers side. The 295/50 is slightly taller than stock, and thus will make your speedo slightly slower than your actual speed. I see no problem in this at all, especially compared to the gains in traction you'll get with those tires.

-Banning.

 

[UNGN]

Originally posted by GrndNatnl
Ok, here's a question that'll make things plain and simple:

What is the fattest 15 inch tire I can put on the rear, that is stock height & wont throw my speedometer out of whack? And that wont really rub, or at least maybe juuuuuust barely if a hard corner is encountered? But preferably no rubbing. I'll be getting new rims for it eventually (probably Telstars), but I need new rear tires sooner then that, and going to have them on stock GN rims for a while.

That's the answer I'm really searching for. I hate having to worry about height / gear ratio / speedo accuracy. So I want to get it right. I wanna go with BFG Radial T/A's.

275/50's. When you buy rims shoot for 8" wide with 3.75" backspacing (3.5 to 4")

To use these tires on stock GN rims, use a 1/4" - 5/16" spacer. this should reduce frame rub tremendously. If you had a T-type You might get away without a spacer.

If you buy Nittos 275/50's your speedo will read fast a couple mph at 60. Everyone elses should be right on.

To improve the handling with wide tires in the back, you may want to consider a Big rear sway bar like an ATR or stiffer springs in front.

 

[GrndNatnl]

Thanks guys! I just wrote all of this down. That's just the information I was looking for.