re: To lock or not to lock...

["Sherry & Chuck Clark" <clark@rmi.net>]

> From:          "Lawson, Dave" <dlawson@ball.com>
> To:            quattro List <quattro@coimbra.ans.net>
> Subject:       re: To lock or not to lock...
> Date:          Wed, 18 Feb 1998 17:16:51 -0700

 Dave speaketh these wise words:
 >snip<

  > This loss of traction happens because the forces on the contact patch of
> the tire overcome the net friction available between the road surface
> and the tire. This can happen because you are spinning the tires on a
> slick surface (i.e.overcoming longitudinal friction) or sliding when
> cornering (i.e.overcoming lateral friction). The levels of overcoming
> the friction forces (also known as driving outside the friction circle)
> depend on your two inputs, the tire and the road surface. The levels are
> very high for a race tire on a dry track, the lowest level is probably a
> race tire on ice. And we all drive some combination inbetween. Snow/ice
> tires on ice increase the friction circle size compared to summer or all
> season tires on ice. At steamboat I believe everyone is driving with a
> snow/ice tire(non studded), but there might have been a few times people
> have been there with all season tires. And it is a real eye opener what
> the differences are. Snow tire equiped cars walk away from all the other
> tires. (And quattros leave FWD cars way behind. BTDT) The point is, on a
> car with all season tires, the level at which the tires loose their grip
> is lower than a snow tire equiped car, so people should take that into
> account.
> 
    As many may recall, I learned the hard way 4 years ago at Steamboat
with brand new D60 A2 all seasons(I know, but hey I thought I'd give it 
a shot) Early in the morning, I had a fair amount of grip as this was well
before the track had been driven on and before all the snow was pushed
aside by flying quattro's. Getting up to speed really wasn't all that hard
with all wheel drive, stopping, well lets just say that it never happened.
I came flying down the long straight at close to 65mph, and as I went 
for a gradual move to the middle pedal, nothing happened. The all seasons
had completely lost all their grip and I was headed for the(then) 7 foot bank
at what was an estimated entry speed of 35 mph. It was the slow motion
ride from hell that luckily left the car with only an engine bay full of fresh
powder and me needing a fresh change of drawers;-) (of course 2 trucks to pull
it from the bank also) The rest of the day, I struggled to keep the car pointed
straight as the track became an ice rink. I had to start braking for the next
corner as the other q's with snows were still on the gas! How frustrating it
was. This past year was quite enjoyable with four Blizzaks! So yes, dedicated
ice/snow tires do in fact make all the difference in the world! Always use
good judgement regardless of conditions as snow tires themselves have limits
too. 

> I don't know the exact situation of your accident, tires, speed, road
> conditions, etc., but what we learn at the steamboat school is
> invaluable.
 snip.

Chad Clark '87 5k Tq
Colorado Springs, CO