Could use help with a rather odd issue

hermit

Looks like a $304 difference, that's not bad. Do these run well in 265/35 and 305/30 as well? Or would I want to size down on these?

MacCool

Unknown. I"m just running stock sport-package sizes Front: 245/40-19 Rear: 275/35-19.

Some people prefer the looks of the bigger tires I guess. Doesn't do anything for me. You'll only get about 13,000 - 18,000 miles out of a set of any of these performance tires. I see no need to overspend. YMMV

hermit

This is true. However, going wider sounds good since I'll be FI. And, I want to make sure my wheels are protected.


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MacCool

As to protecting the wheels, my S-04s protect the rims very well. I'll try to get a picture later to demonstrate.

Friction (traction, in this case) isn't dependent on contact area between tire and asphalt/concrete. It's only dependent on weight of the vehicle and the coefficient of friction (in this case, the nature of the tire compound). Given the same rubber compound, wider tires don't get you better traction. They CAN/DO create or solve sidewall problems. A wider contact patch can allow a softer tire compound such that the sidewalls can support the weight, but wider tire does adversely affect tire wear, as does the necessarily softer compound.

Mind-blower, huh? Look it up. Many people are resistant to the concept that big wide tires don't give better traction, but it's a well-understood concept in physics. I remember the old sandpaper block experiments from high school physics my junior year. I've taken a lot of physics courses since then...neither the concept nor the formula have changed. The formula for friction is:

Fr = μN

where:

Fr is the resistive force of friction (traction)
μ is the coefficient of friction for the two surfaces (nature of the tire compound)
N is the perpendicular force pushing the two objects together (weight of vehicle)

Note that surface area of the contact patch between the two surfaces plays no role in figuring resistive force (friction/traction). If you prize sidewall stiffness as an aid to cornering then you'll actually want narrower tires. Narrower tires allow stiffer sidewalls if the tire compound is the same, as I believe it is in all of these summer performance tires across a given line.



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