Re: [ST] 190 on rear

[Nicolas Nowak <nnowak@xxxxxxxxxxxxxx>]

I was trying to avoid this, but here goes...
For any two tires with equal loading at equal pressures, the contact patch 
area is the SAME.  If you look at extreme cases such as the front and rear 
wheels of a drag racer, then other factors come into play.  But, we are 
comparing a 180 to a 190, so any small differences are negligible.  Wider 
tires do NOT give a larger contact patch area.  Tires are made wider for a 
totally different reason...
- - High heat breaks down tire rubber.
- - As a tire rolls, the carcass flexes and generates heat.
- - Softer rubbers generate more heat than harder compounds.
Here's where the math comes in...
Consider a contact patch of 10 square inches on equal diameter tires.
On a 2 inch wide tire, the patch would need to be roughly 5 inches long.
On a 5 inch wide tire, the patch would need to be roughly 2 inches long.
A skinnier tire will need to be flattened more to create a patch of equal 
area.  This increased flattening creates more heat which breaks the tire 
down faster.  This is why sticky tires are wide, and hard tires can be 
skinny.  A larger diameter tire will also require less flattening to 
achieve a specific contact patch area.

Softer, stickier compounds increase your traction, not tire width.  The 
sticky tires are just made wider to keep the rubber from overheating and 
flying off of the carcass.

Nick
'00 yellow RS


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