Re: I have seen 225/50-15's on a 4kq

[Eaton Dave <dave.eaton@minedu.govt.nz>]

well that's true, but also you mustn't forget that the wider the tyre
contact patch for a given vehicle weight, the less vehicle weight there is
per square cm of the contact patch.  this affects the tyre's ability to
"break" the water surface and bond with the road.  also the more weight the
contact patch has, the more heat is generated in the tyre which is also a
factor in the adhesion equation (wet or dry).

hence, generally speaking (for a given tyre), the narrower the tyre, the
better the wet handling.  within limits of course.  ime, the ur-q is a
better wet-handler with 215/50 15's and 1395kgs, than the rs2 is with 245/45
17's and 1595kgs.

otoh, my old s2 came with 205/55 16's and was undertyred for the weight
(1595kgs).  handling improved noticeably (particularly turn-in, with less
understeer) with 225/50 16's.  klebers (oem) weren't great wet weather tyres
anyway, so wet weather handling didn't suffer.

dave
'95 rs2
'90 ur-q

	-----Original Message-----

	------------------------------

	Date: Tue, 24 Nov 1998 18:13:23 -0500
	From: Huw Powell <human@nh.ultranet.com>

	> If 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)

	actually on this list I finally learned that the tire pressure =
weight
	of the car divided by the contact patch area.

	The problem with wider tires is that the water piled up in front of
them
	has further to go to get out of the way.  Good design will help.
This
	can be even worse in snow, a narrow tire will cut a better path down
to
	the pavement.