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Old 10-29-2009, 12:08 AM
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RallySnake RallySnake is offline
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Join Date: Jan 2002
Location: Northridge, CA
Cobra Make, Engine: Arntz Cobra
Posts: 1,838
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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
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Last edited by RallySnake; 10-29-2009 at 12:24 AM..
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