From: atovorni@engr.UVic.CA (Andreas  Tovornik)
Subject: Re: Big or Small,was FWD or RWD: Which is
Reply-To: atovorni@engr.UVic.CA
Organization: University of Victoria, Victoria, BC, Canada
Date: Fri, 9 Oct 92 17:48:43 GMT

In article 13407@texsun.Central.Sun.COM, dbernard@thewho.Central.Sun.COM (Dave Bernard) writes:
>In Article <51189@engr.UVic.CA> atovornik writes:
>
>>Since I want to get through snow drifts, give me a mid-'seventies Olds
>>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. 
>
>
>
>>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.
>
>
>   
>>   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.
>>The debate is no longer about "FWD or RWD, Which is better?" For winter
>>driving: "Big or Small, Which is better."
>
>	Big heavy cars need more power to displace the greater volume of snow,
>	slush, whatever, that they'll have to face by virtue of their sinking
>	in.

Point taken, It's obvious that bigger cars need more power anyway, so what's
wrong with that?

>	Lighter cars, not sinking is so much, do not need to displace as much
>	gunk, so their smaller engines can be sufficient to get through.

True,true. Lighter cars don't have to displace as much gunk. But are they
heavy enough to displace the gunk between the rubber and the road? Go around
corners aggressively on a wet day in a Hyundai Pony. your nose will slide.
Do it in a Caprice the same way, and no sliding happens.

>	It's a fiction to think that lighter cars do not sink in to some extent,
>	but that extent is limited by all kinds of things- snow density, quality,
>	depth, etc.  The fact that little cars go at all in snow is proof of this.

Alright, that's obvious. I should have stated that some recrystallized 
snow layers that cover powder are too strong to let light cars break through
to traction surfaces where heavier cars would break through without difficulty.
I apologize for overgeneralizing.
	
>	Little cars, too, can have extra weight in the rear, snow tires, studs.  But
>	they usually get by without positraction, unlike the large, heavy, Custom
>	Cruisers.  And since you're mentioning postiraction, we are back in
>	the category of torque to n driven wheels.

I'd still put Posi on any RWD for winter driving. Without it, the wheel
that encounters less traction just spins idly and the wheel with more
traction just sits there. When I lived in Montreal last winter, I always
got up my icy driveway with posi and without studs or chains. If you don't 
have studs or chains, on a non-posi equipped car, one wheel will just
spin and the other will just sit there on that particular sloping driveway. 

My first three cars were a '70 Monte Carlo, a '74 Monte Carlo, and a '76
Monte Carlo. None had Posi, Never got up the drive without studs after
we had freezing rain. My next car was an '88 Escort. This was more useless
for traction than the Montes even if it was a four speed, and I started 
gently in second to increase traction. Too bad there was no place to put
sand bags under the hood :=\

My present car is an '87 Firebird with Posi. To offset the slight forward
weight bias, I put about 100 Lbs of crushed stone(in bags) into the deep
luggage compartment, and get around perfectly on any road that's covered
with gunk.

Andy.