"Matt Whiting" wrote in message
...
More weight means more total friction all else being equal, but it
doesn't, to a first order, change the coefficient of friction. That is
largely a function of the materials that are in contact. The total
friction force is the coefficient of friction times the normal force
(weight in this case) clamping the two surfaces together.

Actually, the determining factor is tire pressure. Now, many trucks and
SUVs use higher tire pressures than what is normally found in passenger
cars, but some are the same or lower. The actual weight of the vehicle
isn't that important, assuming adequate brakes (which, when on snow or other
low-friction surfaces, is the case for basically every vehicle), as long as
the tire pressure is sufficiently high.

As with most generalizations, one cannot simply say "all SUVs are bad", no
more than one can say "all passenger cars are good".

As far as I'm concerned, all you on the pro-SUV of this debate just got
baited into one of the classic stupid debates. You might as well be arguing
Ford vs Chevy or high-wing vs low-wing. The people claiming there's no
valid reason for driving an SUV don't have a clue, and the pro-SUV folks are
unlikely to change that. At the same time, anyone defending ALL SUVs in ALL
situations is just as lacking in clues (not that I see much of that, but
still...)

I feel dumb even bothering to post to this topic...but too many posts have
gone by arguing that weight matters, without a single mention of what really
affects the friction between the tire and driving surface: tire pressure.

Pete