[The Champ]

Originally Posted by NotaT/A

In the end, you need to make sure to use a wheel width approved by the manufacturer of your tires.

And, to the best of my knowledge, there is not currently a 275/60/15 on the market that has a 7" rim listed as an acceptable rim...

[goatless]

Originally Posted by The Champ

And, to the best of my knowledge, there is not currently a 275/60/15 on the market that has a 7" rim listed as an acceptable rim...

Nor was there ever a 1964 GTO that was designed to be run with 15" rims and radial tires. You know you're taking your life into your own hands every time you get in that death trap.

[NotaT/A]

Just for fun I checked with Discount and Tire Rack. Both suggest a 7" wheel with a 275/60-15. They also have 8", 8.5" and 9" as recommendations, but they recognize that people may want to stay with what they have.

From: http://www.tirerack.com/upgrade_gara...=wheels#wheels

SIZE: 15x7
American Racing AR767 Steel Black Painted Product Details
Product Image Size Selected: 15x7
Recommended Tire Size: 275/60-15
Price: $88.00 (each)
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[The Champ]

Originally Posted by goatless

Nor was there ever a 1964 GTO that was designed to be run with 15" rims and radial tires. You know you're taking your life into your own hands every time you get in that death trap.

Ummm.....

Technology changes things every day. My front disc brakes must also make my car unsafe too.

If I were to put seat belts in my car, would that also make it a death trap?

Originally Posted by NotaT/A

Just for fun I checked with Discount and Tire Rack. Both suggest a 7" wheel with a 275/60-15.

Do either of Discout Tire or Tire Rack manufacture a 275/60/15 tire?

I didn't think so...

[goatless]

Ummmm... you miss my point, Mr. Champ. Both 15" wheels and radial tires were available in 1964 and yet the engineers at Pontiac said your GTO would be better suited to have 14" wheels with bias ply tires. They must have had a reason. You have decided to go against those engineers.

Maybe if I put it in your own words you'll understand.

"I think the point that many are missing here is that just because a 15" radial tire can physically be mounted to a 1964 GTO doesn't mean you should or that it's safe to do it.

Car manufacturers have engineers that believe that 14" bias ply tires is what should be used for this car model.

I'm sure that there are good reasons for their belief."

Really, I'm just messing with you. I understand that ideally a 275 would be mounted on a wider rim. We make judgement calls every day regarding our classics, modifying them in ways the original engineers never intended or even imagined. Sometimes it's ok to step outside of the "rules" as long as you understand what is at play. As you can see from others that have posted above mounting a 275/60 on a a rim that is .5" narrower than the recommended range has very little negative associated with it. The worst issue that I've seen are the guys that pop up to tell you you shouldn't do that.

[The Champ]

Originally Posted by goatless

Really, I'm just messing with you. I understand that ideally a 275 would be mounted on a wider rim. We make judgement calls every day regarding our classics, modifying them in ways the original engineers never intended or even imagined. Sometimes it's ok to step outside of the "rules" as long as you understand what is at play. As you can see from others that have posted above mounting a 275/60 on a a rim that is .5" narrower than the recommended range has very little negative associated with it. The worst issue that I've seen are the guys that pop up to tell you you shouldn't do that.

Yup we do make judgement calls every day.

But the original engineers on a 1964 GTO never knew or even dreamed about a 275/60/15 radial tire.

However the current engineers who make 275/60/15 tires have said that a 7.5 or 8" rim is the minimum width rim that should be used. I believe that these engineers have a clue about how the performance of that tire will be affected by the narrower rim.

I just think it's odd that when making a change to improve the performance of a car that one would knowingly do something that will most likely hamper the performance.

Do whatever floats your boat.

[Formulajones]

You guys crack me up. I don't think a 1/2" makes a damn bit of difference on a street car. You are talking a 1/4" per side. Even at 1" you are only talking a 1/2" per side.

I understand the whole "pulling the sidewalls in" idea, but a 1/2"??? Really? I wouldn't worry about it. Adjust the air pressures and forget about it. I've done this for many years and never experienced any ill affects, car drives fine, no center tread wear, and personally I like some sidewall on my cars anyway, gives me some curb rash protection

A track car is a different story. The "ONLY" time I really prefer a wider rim on my 275's are on my drag radial car, because in that instance, I lower air pressures at the track and want the most contact patch I can get for a small tire car making big power. There's a reason you see them mounted on a 10"+ rim in the 275 radial classes, although I don't care for the look, but you work within the rules of the class.

Hang on, I'll post a pic of my fathers car that will stir the pot some more

[Formulajones]

Here is a shot at the Pontiac Nationals,

That's a 295/65-15 drag radial on an 8" rim. Look up the recommended rim width on that and I'll guess it's 9" or more....

But, it works, and works good. 1.5 60 foot times and it hangs the front tires. He's used this setup for years.



Here it is at rest...



Personally I love the sidewall bulge look. I never jumped on the big wheel and rubber band tire bandwagon, I just can't stand the look of a wheel that looks as wide as the tire is. I've had no love for all this pro touring stuff.