295/50 15 vs. 275/60 15? Which is better?

[timsullivan]

Okay, thanks for the feedback and opinions on BFG vs. Goodyear’s. Now, if you’re a poor boy like me and can only afford those stupid, ridiculous and hard as nails old 15" tires and wheels which is a better REAR tire size when running 255/60-15 on the front tires: 275/60-15 or 295/50-15 and why in your judgment? Thank you in advance for your thoughts.

[Gunner]

Wider is always better. I don't think there's any justification for the narrower tires except when you need to save money or can't get the fatsos.

[RodKnock]

Originally Posted by Gunner

Wider is always better. I don't think there's any justification for the narrower tires except when you need to save money or can't get the fatsos.

+1. What he said.

[Got the Bug]

Ditto. No reason not to go wider on the back. If you want to stay on a budget, you might want to consider the Firestone 500 over the BFGs or the GYs.

http://www.tirerack.com/tires/TireSe...r=15&x=35&y=13

http://www.tirerack.com/tires/TireSe...r=15&x=50&y=10

[Rwillia4]

Agree the wider tire is better. Not only from the fat perspective but also the sidewalls are smaller (by about 3/4in) so they "should" handle better.

[RallySnake]

Ok, I'll bite. Wider is NOT always better. Better tires are better. I have run more than a dozen sets of tires on my Arntz over the 20 years I have been driving it. My goal has always been to make it handle as well as my old 1972 BMW 2002 Tii. You might think that's easy, but I'll point out that a BMW 2002 won the 2009 Targa Newfoundland Rally. These cars love to be thrown into a corner sideways and maintain a balanced slide all the way through. I have only managed to get close to that with 275/60/15 Toyo S/T tires on all four corners of my Arntz. Tires that big do not look good on the front of a Cobra. Most Cobras run 295's on the rear and 235's on the front. It is almost impossible to get tires of these disparate sizes to give you a balanced breakaway unless you can move some weight towards the rear. Otherwise, they tend to understeer right off the road. If you firm up the rear end with a big enough sway bar, you get a very twitchy car. I have spun out many many times on autocross tracks and can testify to this.

After the winner of the One Lap of America's Classic Division in a Superformance Cobra, Doug Reed, told me that he used Yokohama Avid S/T's, I bought some. I went with 275/60/15 in the rear and 255/60/15 in the front. Did I mention that 275/60/15 tires do not look good on the front of a Cobra? Well, the 255's are smaller and much more acceptable. By playing with the sway bars and tire pressures, I have gotten the car to be very balanced. However, it is still very twitchy and so I throw the car into the turns while trail braking and try to catch it with moderate power as the rear comes around. Sometimes I catch it and look like a hero, sometimes I don't and look like an idiot. Either way, it's really fun!

So, with 295/50/15's on the rear, what are your choices for the fronts that will give you similar contact patches for balanced handling? If you think 275's look funny on the front, the answer is......nothing. I could mention that larger tires cause much more aerodynamic drag and much lower top speeds, But you probably would not believe how much difference that makes. Just look at your Bonneville racecars.

I welcome anyone's contrary viewpoint, if you have experience to back it up.

When the Yoko's wear out I will be looking real hard at the new Mickey Thompson Sportsman S/T tires. The sizes are right and if the compound is softer than the Goodrocks, they may be a winner.

RallySnake

[Ralphy]

I am running Goodrich TA's, 295/50 15's on 10 inch wide wheels. When I use a tire calculator. It shows that I can run a 8 inch wheel minimum. If I do use 8 inch will this narrow my section width and if so does anyone know how much? I have noticed a little tire rub inside and outside the well. I would also like to consider lowering the car, which I am looking for more clearance.

[greg schroeder]

Here are 275/60 15s(Mickey Thompson ET Street drag radials) on a Superformance. They stick and don't throw stones when cruising. They handle much, much better than the BFG radial TAs which came on the car, but won't last as long.





In the next link below are 325/50 15s. They look a bit big to me.
325/50 15s

The 275/60 15s are in the video link below

[Tom Kirkham]

+1 for Rally Snake.

On the street a narrower tire will feel better. This is especially true in the front. A wider tire for a given rim width takes longer to take a set than a narrow tire. I do not like 295 tires. Lets face it on the street maximum G's is something rarely if ever attained. If you are looking for maximum G's on the street you will not have your license or freedom very long. On the street you are looking for balance and feel. The feel of the car is something you can enjoy every moment you are driving the car. On my Sebring car I put 225 (6.5 in rim) and 245 (8.5 in rim). These are also the tires I put on the 427 car we ran at Bonneville. Driving this 427 car on the street felt awesome. Something to think about is most of our cars have close to a 50/50 weight distribution. This has a direct correlation to the tire size...

Here is an interesting article on the subject.

http://www.modified.com/projectcars/...t_2/index.html

[Gunner]

I'll clarify my comment - which I thought was self-explanatory, but some valid points have been raised.

If we had unlimited tire choices for these cars, I'd never say anything as absolute as "wider is always better." But our choices for original-spec tires have dwindled until finding adequate 15-inchers is a chore, and no really good options remain. If an owner wants to go to 17-inch wheels and not mind the variation/distortion in looks, there are scads of tires to choose from and a set more closely coupled in size would have benefits on both street and track.

If you're in the group leaning towards originality and you want to stay with 15s, I don't think there's any question that the widest tires you can find and fit on the back are what you want. Less for handling than to try and safely hook 400-600 HP to the ground in the hands of a driver with (likely) little or no race experience. Getting as much meat up front to correspond is the logical followthrough.

Experienced track or autocrosser? 17s okay? One set of rules.

Average Cobra driver? 15s mandatory? Different set of rules, beginning with "wider is better."

[RodKnock]

Again, I agree with Gunner.

When the Yoko's age out, for about $1,500/set, I plan to get the "wider and better" tires offered by Avon.

[Gunner]

Originally Posted by RodKnock

I plan to get the "wider and better" tires offered by Avon.

At which point you'll need to rename your car "Stratford."

$1500? Ouch, you're right. I had glanced at the price sheet and had come away with a vague notion of $1200. Plus shipping, mounting, balancing... ow. But they do seem to be as good a tire as ever made in this size combination.

[Chilibit]

+ 1 for RallySnake and Mr. Kirkham

My experience argues for balance and using corner weight to guide the choice of adhesion. Drag racers play by different rules. The rears drive and the fronts have to turn and brake. So the logic is not simple. Let me change that. The logic is simple, but getting good empirical data can be difficult.

I readily admit that we are comfortable seeing fairly large staggers. My car is that way but I really doubt it is ideal for a road car on the track or the twisties.

No, I cannot prove my position.

[RodKnock]

Originally Posted by Gunner

At which point you'll need to rename your car "Stratford."

$1500? Ouch, you're right. I had glanced at the price sheet and had come away with a vague notion of $1200. Plus shipping, mounting, balancing... ow. But they do seem to be as good a tire as ever made in this size combination.

Well, you call it "Shirley" or whatever you would like, but other than the price, the V-rated Avons have had outstanding reviews.

At any rate, most decent tires for today's modern high performance cars are very expensive. I make every attempt to treat my Cobra to the best that's available. If and when I find a set of magnesium Halibrands, I plan to install the Avon's on them.

[Gunner]

No question that the Avons are the hot ticket - and much kudos to Avon for producing them and the well-connected Cobra/GT40 nut who pestered them into doing so. But they are some of the most expensive tires on the market as a result. I put top-end all-weather tires (all Eagles, right now) on my street cars and rarely spend more than $150-180 a tire from Tire Rack.

But there are no other options these days for speed-rated, grippy, DOT, correct-size rollers... so I'll fork over that wad next summer without a bit of complaint.

[SuperHart]

It's really not that simple to choose the proper tire. One consideration I didn't see mentioned is tire diameter. Of course, you want a wider tread in the rear than in the front. If you stick with the same aspect ratio for both front and rear, the wider rear tire will also be taller and therefore cause the car to appear tilted forward. The taller tire may also throw off your speedometer calibration. Remember, your speedo is set up not only for a specific rear end ratio but also a specific tire diameter in order to maintain accuracy. Go with a taller rear tire and your speedo will read slower than your actual speed.

All that said, going to a 50 aspect ratio rear tire will allow you to run a wider tread without using a taller tire. You want all four tires to be approximately the same diameter or height so the chassis sits level. Assuming a 15" rim diameter, I recommend 235R60-15 in the front and 295R50-15 for the rear running on 8" and 10" rims respectively. They will ride better than a bias ply tire on the street and give you better longevity. I know I will take some heat here but I have used the Cooper Cobra tires in the sizes above with great results. They are relatively inexpensive and I kinda like the Cobra insignia molded into the sidewall. In my opinion, there is no sense in using a track only tire on the street other than getting that neat GOODYEAR sidewall. At one time I ran a set of Goodyear Billboards. I had to change the entire alignment on my car, they rode like truck tires, I didn't like the way the car handled and they picked up and threw every bit of gravel they ran over causing many little chips and dings in my paint. Because my car is a cruiser and not a racer, I soon returned to the Cooper Cobra radials and have been very pleased ever since.

Just my $.02.

[Gunner]

You're correct that tires should be chosen to be as close in diameter as possible, but within a half-inch, front/rear, is plenty close in most cases. You may need to re-adjust your suspension, rake, ride height etc. and speedo gearing, but such tweaks are always a part of tire changes on a high-performance vehicle.

I think there are more important considerations than absolute tire diameter or a modest front/rear diameter difference. Choose by those considerations and adjust to a diameter change. (All within reason, of course...)

[Buzz]

Originally Posted by Tom Kirkham

+1 for Rally Snake.

On the street a narrower tire will feel better. This is especially true in the front. A wider tire for a given rim width takes longer to take a set than a narrow tire. I do not like 295 tires. Lets face it on the street maximum G's is something rarely if ever attained. If you are looking for maximum G's on the street you will not have your license or freedom very long. On the street you are looking for balance and feel. The feel of the car is something you can enjoy every moment you are driving the car. On my Sebring car I put 225 (6.5 in rim) and 245 (8.5 in rim). These are also the tires I put on the 427 car we ran at Bonneville. Driving this 427 car on the street felt awesome. Something to think about is most of our cars have close to a 50/50 weight distribution. This has a direct correlation to the tire size...

Here is an interesting article on the subject.

http://www.modified.com/projectcars/...t_2/index.html

Interesting, because I thought that wheel/tire combo looked great on the Bonneville car.

[Gunner]

Let's face it, spoked baby pram wheels would look good on that car.

As for the tire sizes... I'll take Tom's word that it drove great on the street, but Bonneville has no curves and cars typically run on the narrowest tires they can get away with to reduce weight and drag. Apples and kumquats.

[Buzz]

Lol! Here are some more views for your perusal.