Date: Sun, 05 Jun 2005 02:57:07 GMT From: "Stephen B." <myspamnospamd9.net> Subject: Re: Re: Funny quote about the SAAB 9-3 based Cadillac BLS
<snip> > Where do some people get the idea that a narrow track ( or Tread) makes > a better snow tire? > > Have they forgotten the elementary formula that friction + the > coefficient of friction X the force(that is the mass of the car)normal > to the surface. > > It is independent of the area in contact. The bigger that area the more > the force (mass) is spread out. > Malcolm I think you are looking at this to simplistically. On a nice clean street the forces to roll a wheel are more complex than that, and once you add in a few inches of snow the formulas really get complicated. When driving in snow, you will be applying a force to move forward. The snow you are running over will be pushing the wheels back the other way (higher rolling resistance from packing down the snow). Wider tiers have to compress more snow, so need to apply more force to the road to get to the same place, increasing chances of slipping. Also, don't forget that the skinnier tier has to move less slush to get down to the road. Once the tier makes contact with the road, slipping is much less of a problem then when riding on a half inch of slush. Narrow tiers are far less likely to hydroplane than wider ones. -- Stephen B.