[1969GTO]

I have a 69 GTO and I want to increase my ground clearence .
I am running ralley 2- 14x7 wheels with 245/60/14 tires.
I will be needing new tires soon and want to know what would be the tallest and widest tire I could use on the car with out tire rub.
OR
I have 2-ralley 2 wheels 15x8 and could buy 2 more and buy new tires for those wheels but still need to know what tire size would be best hight and width for the GTO.
any ideas?

[The Champ]

You should be able to "safely" run 255/60/15's on the back - these are about 27" tall vs. the 25.6" tire height of your 14's.

You may be able to fit 275/60/15's - these are about 28" tall.

You will be able to fit 235/70/15's - these are about 28" tall.

You should be able to fit 255/70/15's - these are about 29" tall.

On the front - 235/60/15's are about 26" or a 225/70/15 would be about 27.5".

Lot's of options - just remember that changing the rear tire diameter will affect your overall gearing of your car. Those 255/70/15's will really raise your year end and really lower your RPM's at the same time.

Assuming a 3.23 rear gear and a 4spd tranny with your current tires you're turning around 2550 RPM at 60 MPH. Those 29" tall 255/70/15's will drop your RPM's down to 2250 at 60 MPH - effectively turning your 3.23 gears into about 2.85 rear gear.

[1969GTO]

just what I was also looking to do rpm wise,I have 3.90's in the rear and t-400trans.
the car is street strip,I have slicks for the track.
thank you....mike

[studda]

I have 15X8 wheels on the back with 275/60/15 and 245/??/14 on the front. It gives it kind of a raked stance. You could just get tires put on those 15's for the back for now and put some on the front when you get two more 15's. I have a TH400 with a 3.90 as well. It doesn't do too bad on the highway. The 275/60/15 are 27.99" tall.

[1969GTO]

studda,
do you have any pics of the wheel tire combo on your car?
I would like to see from the sides and back.
mike
mjmattiac@twcny.rr.com

[1978 T/A]

I personally don't like the look of a 28" tall tire in the back. Unless it is a slick of some sort. I run a 235/60/15 in the front and a 275/50/15 in the rear; 26" in all 4 corners.

[David Jones]

I have 255/60-15's on 8" Cragar's out back and 245/60-14's on 7" in the front. You might get a little taller front and back but after it's all said and done you MIGHT gain an inch ground clearance. Maybe.

[studda]

Originally Posted by 1969GTO

studda,
do you have any pics of the wheel tire combo on your car?
I would like to see from the sides and back.
mike
mjmattiac@twcny.rr.com

There are a couple pictures in my album on my profile page. I looked and the front tires are 215/70/14.

[The Champ]

Originally Posted by 1978 T/A

I personally don't like the look of a 28" tall tire in the back. Unless it is a slick of some sort. I run a 235/60/15 in the front and a 275/50/15 in the rear; 26" in all 4 corners.

FWIW department - the original equipment tires on a '69 GTO were 27" so your 26" tires are 1" shorter than stock.

A 28" tire only goes .5" higher up into the wheelwell than the orignal tires - not enough to change the appearance much from the stock tires.

[marshallbeach]

Good web site for tire sizes.

www.turbinecar.com/tires.htm

[kookykrispy]

I also have 275/60 on a 15x8 wheel on the back of my 68. I think it looks great and is the perfect tire/wheel size for the rear of my car. I like the 28" tall tire for highway cruising, but I need to re-gear my speedometer since it is reading alot slower speed than the car is actually traveling. There's some pics on the 68-69 pic thread (scroll all the way down the thread for all the pics) if you want to check it out:

http://forums.maxperformanceinc.com/...=639898&page=9

[Grand73Am]

Originally Posted by 1969GTO

I have a 69 GTO and I want to increase my ground clearence .
I am running ralley 2- 14x7 wheels with 245/60/14 tires.
I will be needing new tires soon and want to know what would be the tallest and widest tire I could use on the car with out tire rub.
OR
I have 2-ralley 2 wheels 15x8 and could buy 2 more and buy new tires for those wheels but still need to know what tire size would be best hight and width for the GTO.
any ideas?

15x8 Rally II's? Are they aftermarket reproduction wheels?
Factory Pontiac Rally II's didn't come in 15x8. 15x7's are as wide as they got. If you measured across from outside edge to outside edge and got about 8", then the wheels are 7" wheels. The width is measured inside the wheel lips, where the tire bead seats are. Personally I like 245-60-15's on 15x7's.

[Overkillphil]

I have 255-60-15's all the way around on my 70 and with 15x7 Rally II's and no rubbing issues whatsoever, even with the HO Racing springs/lower than stock stance.

[1969GTO]

you can but 15x8 rims all over the place, Coker,Wheels Vintique etc.

[kookykrispy]

I have run 275/60r15 on 15x7 rally II's out back on my '67. They fit well, look great, and tucked inside the rear wheelwells with no rubbing. The '68-69 rear wheel well has a little more room than the '67, so the 275/60 is a slam dunk.

You might be able to run a M/T drag radial 275/50r15 but I think you probably would want an actual 8" wide wheel and you might need to roll the rear fender lip.

[Grand73Am]

Originally Posted by 1969GTO

you can buy 15x8 rims all over the place, Coker,Wheels Vintique etc.

I know...that's why I asked if you had "aftermarket wheels" or factory wheels, since you didn't say one way or the other. Since some people might not know that there aren't factory 8" rally II's, or know how to measure the width properly, and think they have 8" wide when they have 7", I had to check to make sure you weren't one of those people who don't know . Now we know for sure that you have 8" wide aftermarket Rally II's and can give advice based on that.

[The Champ]

Originally Posted by kookykrispy

I have run 275/60r15 on 15x7 rally II's out back on my '67. They fit well, look great, and tucked inside the rear wheelwells with no rubbing.

A 7" wide wheel is too narrow for a 275/60/15. I know people do it - but the MINIMUM recommended width is 7.5" and most people run at least an 8" wide rim.

I have 255/60/15's on a 7" wide rim and wish I had 8" rims as they "balloon" more than I like on a 7" rim. 255/60/15 is the largest/widest tire that is safe to run on a 7" wide rim.

[1969GTO]

I am not hearing any thing good about 14x7 wheels,why is that?
Does everyone just go to 15?

[The Champ]

Originally Posted by 1969GTO

I am not hearing any thing good about 14x7 wheels,why is that?
Does everyone just go to 15?

Because unless you are going to run bias ply redlines, you can't get an appropriately sized radial tire in a 14". The original tire height on most GTO's was about 27". Your reasonably wide 245/60/14's are too short (25.6" tall"). If you go to a 225/70/14 (26.5") you're getting closer to the appropriate tire height, but aren't wide enough for what most of us want on the rear end.

Bottom line - they don't make a big enough tire in the 14" tire size to satisfy what most of us want on our cars

[1969GTO]

Originally Posted by Overkillphil

I have 255-60-15's all the way around on my 70 and with 15x7 Rally II's and no rubbing issues whatsoever, even with the HO Racing springs/lower than stock stance.

do you have any pics of your car?