Lockers behavior in snow

Todd Phenneger tquattroguy at
Wed Dec 11 13:02:47 EST 2002

Heya everyone,
  This doesn't have any direct Audi Content other than the
thread this was taken form mentions Audi's often.  (I constantly
have to correct these guys, you CANT drive a 200 on the freeway
with both diffs locked, c'mon) (unless you make some wiring
changes anyhow. :-)
  ANyhow, we all drive in snow and some of us have lockers in
back.  (RICH, PAT, TODD, and anyone other cool people that drive
OLD Audi's)
  Anyhow, heres the post.  If you have a desire to view the
entire discussion go to    click on bulletin board, go to Discovery
Technical discussions. and THe thread is....Lockers bad on snow
and ice, why?    ITs actually a good read if you have the time.
ANd you dont have to subscribe to read or post messages.
From:  Muskyman

OK some more clerification on my post.

snow is a very wide spectrum word. there is a balence point of
resistance between forward travel and side slip that makes a big
difference in how a vehicle acts.different snow condition need
different set ups to be ideal.


when snow is deep enough to give resistance to side slip say 4"
or more a locker starts to be a big advantage. also when aired
way down the tire becomes longer along the side then it is
across the width so once again lockers work well because the
resistance to side slipping is there to allow the tire to
continue digging instead of sliding sideways and begining to
float. on very deep snow lockers are a huge advantage because
they do float. I go winter wheeling all the time. in fact its my
favorite time to go. I can lock my lockers and float the whole
truck on top of bottomless snow that you cant even think about
crossing without snow shoes. if I unlock the lockers one side
will sink and the truck will get stuck. I run 13.5" wide tires
at 4psi to maximize the size of the traction pad to help the
tire get on top of the snow.

ON the highway

on freshly plowed snow covered or ice covered roads(the people
of upper migh wont see the actual road now till spring) at road
going pressure the tire contact patch is wider then it is long.
as soon as the tire breaks traction it will want to slide to the
point of least resistance, in this case that will be sideways.
in these types of conditions lockers will be a major hinderance
because both tires will want to float togather, and there is
less traction floating then when biting down

so now if you want to improve your on road snow going traction
you need to increase your surface pressure and decrease your
ratio of width to length of your traction pad. the way to do
this is by putting taller skinnier tires on. the taller tire has
a larger circumfrence making your traction pad longer. the
skinny tire reduces your forward width resitance and the overall
reduction in traction pad size increases your surface pressure.
now in these conditions all the locker does is make the two
traction pads work togather and this works against you because
every time one breaks free they both do.

want to see this in action ? go talk to any company that plows
for a living and they will be running tall skinny tires.

once again as I said before of course you can drive a locked
truck on the street in snowy condition but in most street
related snow condition open or very loose LSD is a much better
way to go.

well keep it outa the ditches


Do you Yahoo!?
Yahoo! Mail Plus - Powerful. Affordable. Sign up now.

More information about the quattro mailing list