haljensen

Physics and common sense do go together. My little brother was a Physics Professor @ Brandeis and one of his ways of "solving" a problem or looking for a solution was to apply extremes. Given the OP's criteria the posted statement is false. There is no mention of the direction or type of the load, type of tire, inflation pressure, etc.

A taller narrower tire could have the same rubber on the road as a shorter wider tire but that wasn't the OP's statement.

The 10 1/2' drag classification doesn't say anything about diameter, just a limit of 10.5" wide. If somebody could build a tire 52" tall (and a car with gears to handle it) the car would have a much larger (longer)footprint than a 26" 10.5" wide tire.

Bigger diameter gives a longer footprint, wider gives a wider footprint. A 26.7" tall, 345mm wide tire puts more rubber on the road than a 26.7" tall, 285mm tire. The load my be different but the footprint does get larger with a wider tire.

owebo

You would think so.......but this is one of those times where physics is at odds with common sense....

ALLEGRO

I think that some of you missed the point of my earlier post. I chose to be as simplistic as possible and make my point so that it could be well understood. My first statement is the MOST important part of the post.

If two tires, one wider than the other, are at the same inflation pressure, they will support the same amount of vehicle weight, with the same amount of contact to the ground.

That said, I did not include dynamic issues, nor did I include the variables of tire construction or technology. The fact is: that with given pressure and given load-weight, footprint size (square inches) is identical in a static state, regardless of tire width.

HOWEVER, dynamics do play a roll, as do tire characteristics. As a result, my post is even better proven.

Top Fuel Dragsters utilize tires that accommodate both desires. They use low pressures that present a BIG footprint (read contact patch) at rest and at initial launch, then only to grow in circumference while reducing in width producing a narrower and longer contact patch that accentuates high-speed acceleration, and higher overall gearing. When these cars do have side-slip, they most always go out of control.

Road-Racers embrace the virtues of wide tires and the "wider than longer" contact patch. This type of patch supports lateral loads better than the opposite, therefore allowing for higher cornering speeds, i.e., faster lap times. They optimize tire width to aide in lateral grip and straight-line breaking. Too wide = NOT GOOD while too narrow = NOT GOOD. In addition to optimized tire size, they also optimize tire pressure to ensure adequate contact-patch to successfully match the challenge.

Physics is physics, and traction is inherently separate from the scientific term of friction. Track tires are most always wider, and snow tires are most always narrower.

Okay, the dissertation is over.....WIDER always looks BETTER

Paul330

Allegro, let's take your equation from above: 1000 lbs / 33.3 psi = 30 sq in. Now let's apply it to a run flat that is holding up 1000 lbs at, say, zero or 1 psig. What's your contact patch then? Tires don't behave ideally like you suggest. Also, why doesn't the actual data mentioned in FortMorganAl's link above support your case?

ALLEGRO

It is not that it does not support my position, I am just trying to keep it simple and avoid all the dynamics of tire technology and rolling dynamics. My entire point is one from PHYSICS. I am not trying to one-up anyone or make anyone angry.

I guess I will just respectfully bow out.