From: gould@theory.TC.Cornell.EDU (EWD)
Subject: Re: Big or Small on H2O Gelations
Summary:  depends
Organization: Cornell Theory Center
Distribution: na
Date: Fri, 9 Oct 1992 01:35:12 GMT

In article <1992Oct8.212700.21152@sol.UVic.CA> atovorni@engr.UVic.CA writes:
>Custom Cruiser with ten 1"-thick sheets of 4X8 plywood in the back. The car
>must have Posi, and studded snow tires. Nobody would keep up with me. 

Got to agree here, Pro Rally just hasn't been the same since they banned
those 8 quart GM wagons :-).

>Why use snow tires with big treads?
>
>Ans: The big treads force the snow into spaces between the treads, getting
>     down below the snow, onto something more grippy. I prefer studs,even.
>     Light little cars don't have the necessary weight to sink down, dis-
>     place the snow and get to some surface (blacktop or gravel or concrete)
>     that roads are made of. These little cars are the ones that wipe out
>     in the white stuff more easily regardless of FWD or RWD than big, 
>     heavy machines with blocks of concrete(or other suitable heavy stuff) 
>     in the trunk and RWD.

(Don't need studs.  Don't want 'em.  YMMV)

I'd say the function of thread openness is to forge the snow better to
the shape of the thread.  Not so much to get below the snow as you suggest,
but to turn it into "something more grippy".
    
>   Let's face it, you cannot change the laws of physics. Big cars by
>their weight get more traction and better control on snow or ice than 
>little cars by their lack of weight.

But heavier cars have more mass to accelerate, so you must be implying
that heavier cars make more traction in proportion to their weight.
This can be true, but it's not a function of the weight of the car,
rather a function of the width of the tires.  A 5300 pound Visa Bruiser 
with 255/70-15s has effectively much narrower tires than a 2050 pound
Sirocco with 195/60-14s.  Put skinny tires on the Sirocco and we're
back to discussing the relative merits of the cars.  If you had ever
observed or participated in actual contests of speed on frozen surfaces
you'd know enough to keep right on going with those sheets of plywood
and build yourself an ice fishing shack instead of carting them around.

It is true, however, that the classic silo staves in a Delta Royale
will do better in dozing situations where it's no longer a matter
of slicing through the material with the tires, but rather barging
through with nose of the vehicle and dragging its belly.  If you've
ever wondered about buying rental cars, consider the Camaro I got
stranded with in deep snow in the mountains of New Mexico.  Ended
up level full of rocks from top of the front seats back and took a
good half hour of backing up the hill behind and charging the hill
ahead before we got out of the valley.  I never knew automatics could
make smells like that.

>The debate is no longer about "FWD or RWD, Which is better?" For winter
>driving: "Big or Small, Which is better."

The more the situation tends towards wallowing, bigger is better.  
The more it resembles a road with less than, say, 12 inches
of snow, or packed snow, or ice, then more smaller is better, at least
according to the checkered flag.

>Andy.

Eliot

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