Re: I have seen 225/50-15's on a 4kq (now Contact Patch)

["Steve Bigelow" <sbigelow@sprint.ca>]

Ken Keith wrote
>It's possible to have too much tire for a car.  If you the amount of 
>weight on the surface area on the ground is too little, the tire won't 
>have enough pressure (not air pressure, but downward/gravity pressure) on 
>the road to give good grip.

>So, if the tires are too wide, things like hydroplaning are excaserbated. 

>That's kinda why tractor tires are tall and skinny, I believe.


I believe it is contact patch _shape_, not size. 
	Size is determined by vehicle weight and tire pressure. (Damn, I wish I
could find my copy of "How to Make Your Car Handle...) 
	Imagine a balloon on your tabletop. Contact patch? Near nothing. Use
another balloon, another shape, same result. Now add downward pressure
(vehicle weight) or lower the pressure in the balloon and the contact patch
goes up. Think if you knew the the pressure applied and the pressure in the
balloon you could predict the contact patch? Of course you could, you
clever lister, you......:)

	Formula cars have wide rubber for a contact patch that is wide, for
cornering stability and leverage. Top Fuel dragsters have tires at the
business end that are tall, for a contact patch that is long, for
accelerational stability. Tractors have tall skinny tires to improve the
per acre yield, by increasing the numbers of rows. Less tire, more corn!
(that, and so they don't get stuck!) OK, I'm guessing on the tractor
issue.....

	Of course the above is 'gross' patch size, and disregards the open areas
of the tread. It also disregards rubber compound, sidewall stiffness, and a
host of other things. But that wasn't in the subject, so there.....

Steve Bigelow ICQ 22399818
Discreet Dungeons Ottawa Ontario
'84 5ks "Audrey", Zermatt silver, Husco armrest/cupholder, Bosch H4/H1
quads
'82 Coupe (previous)