street tire traction question

[85_SS_302_Coupe]

With a taller tire, the need for a higher gear ratio is greater.

I talked to the local speed shop guy about racing with street tires, and he says that the usual lowering of tire pressure on slicks does not apply to street tires, and that you should OVER inflate them?!? I told him he was nuts but he said pump them up to about 40psi and launch hard and they should hook better. I figured he was trying to BS me so i never tried it, and i've never seen any improvements from running lower PSI either.

 

[crazypete]

I pumped my street tires to 75 psi once (what the little popup peg said at least) and it was interesting. Like having no suspension and riding around on 4 rocks. Monster peelouts though. I doubt this is the winning startegy as I had no traction to speak of coming off the line.

 

[ramjetlx]

You dont want to lower the psi in street radials. Its an old technique that doesnt apply to current street tires. Keep them at normal or a bit higher pressure, just have to expirement.....

 

[fiveohGT]

Isnt the sidewall number based off a percentage of the tire width? A 17" x 10"/315/35 will hook better then a 17" x 9"/275/35 because it will have a greater width and sidewall.

or

Does the extra weight from a 10inch wide wheel/larger tires make a significant enough difference over the 9inch to damper any power?

 

[srothfuss]

Here is my theroy: The reason that a Taller tire will 'hook' better is because you will get more sidewall distortion. This distortion allows for more of the tire to remain in contact with the pavement.... Thus increasing traction.

Now, as stated prior.. There are many factors. Weight being the most important.

 

[super302]

Here is my theroy: The reason that a Taller tire will 'hook' better is because you will get more sidewall distortion. This distortion allows for more of the tire to remain in contact with the pavement.... Thus increasing traction.

Now, as stated prior.. There are many factors. TIRE COMPOUND being the most important.

fixed

 

[Biggeley]

When it comes to standard radial street tires, the best tire pressure is the one that gives you the greatest contact patch with the road.

Overinflating the tires will make only the inner part of the tire to contact the road.. Underinflating makes the outer edges of the tire contact the road.. Proper inflation allows the entire surface of the tire evenly contact the road.

The easiest way to tell if you are underinflated, overinflated, or properly inflated is to do a few quick launches on blacktop. You can tell from the resulting tire tracks if you are getting proper tire contact with the road, as the tire marks should be black and even across the entire width of the track.

Interestingly for my street tires, 32 psi in the left tire and 28 psi in the right tire give me a nice even patch on the ground.

 

[Crawlin302]

I have 235/60/15 Futura GLS SuperSports from pepboys under my 590rwhp car, and it hooks amazingly. Just as good as a Nitto 555R or a, MT ET Streets

 

[srothfuss]

fixed

Ah... True...