Contour Enthusiasts Group Archives Forums General General Theoretical Tire Question (EdwardC, I need a physics lesson here)

Don't take this the wrong way.

But how does a wider tire turn into a larger contact patch?

I was under the impression the given two tires of the same construction, one simply wider than the other, and the same air pressure in the tire, that the area of the contact patch is the same. It is only the shape that changes.

(In fact, I learned that tidbit in my freshman Physics course, IIRC.)

I realize there may be some slight difference. But assuming the only change is the width of the tire (the sidewall supports no more or less weight or it's contribution relative to the weight supported by the air in the tire is insignificantly small) doesn't the area of the contact patch remain the same.

This is what I'm struggling with. I believe the contact patch occupies the same area, given the same air pressure in the tire. The only difference is the shape.

Is that wrong, or too simple?

TB