Hydroplaning Contact patch

Cody Forbes cody at 500tq.com
Thu Jun 3 00:05:13 EDT 2004

>   Does the vehicles tire contact patch get smaller when linear
> (straightline)
> > speed is increased?
> No, but as the speed becomes a significant fraction of c, the car gets
> shorter.  From where we are standing, anyway.
> -- 

I think here that yes the patch becomes smaller, but not at any speeds we
would be dealing with. As speed increases the centrifugal (sp?) forces will
cause the center of the tire to move outward, which would mean less and less
contact patch as the tire becomes less flat and more looking like a
motorcycle tire. I know this is an issue on speed trials cars because
special tires are made that actually bow inward when sitting still (as in
when sitting on the ground the center of the tire will actually have
clearance from the ground and only the outside edges would be touching the
ground) so that once your up to speed the tire expands to become flat. That
way you still have decent control of the vehicle once going quickly. The
thing here though is like I said - this is speed trials, not real world
street driving.

-Cody Forbes

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