snow chains/cables on a lowered car...

[SailingFC at aol.com (SailingFC@aol.com)]

In a message dated 11/23/2003 2:19:06 AM Pacific Standard Time, 
treed2@wsu.edu writes:

But if the cable chains are rotating around the tire, then doesn't that
mean they're just too loose? I mean, there's friction between the little
metal cylinders (rollers) and the (rubber) tire surface and friction
between the rollers and the ground. If these forces are equal (ie.
coasting) then the rollers would have no reason to spin.

>> The way I see it, each time the cross cable touches down, the rollers bite 
and turn a bit between the tire and road.  This turning moves the cable 
around the tire, but with the rest of the cables wrapped around the tire, it binds 
up and limits the movement.  So each time another cable comes in contact with 
the road, the cable moves a little again.  Yes, I would guess in a coasting 
mode the rollers don't spin much.<<

With the wheel 'burning out', or while locking the brakes, something has
to give. Either the roller sticks to the ground and the wheel spins around
inside the cables, or the roller sticks to the tire and gets the crap
rubbed out of it by the abrasive road surface.

>> I think a little of both is happening, on asphalt the roller probably have 
full bite and must rotate.  On ice/snow the rollers claw through it and spits 
it out the back.<<

The middle case is the one I'm not so sure about (normal acceleration or
braking). If the friction between the tire and the roller was zero, the
tire would just spin inside the cable chains and you wouldn't go anywhere.
But this isn't the case -- there has to be some friction and this is
determined by how tight the chains are. I think its possible (but I don't
know) to tighten them enough that normal, slow driving will result in the
chains not moving around the tire. I -don't- think its likely you'd be
able to tighten them enough that they won't try to spin when you're
burning out or locking the brakes on pavement.

>> If the entire tread area was covered in cross cables and rollers, I think 
the tire might have more of a tendency to spin inside the cables.  But because 
there are gaps in the cross cables, there is this releasing of the cable and 
then grabbing again as the next cross cable comes down.  And because the rest 
of the cable is grabbing on to the tire, it only moves a little.<<

I guess that's sort of a problem. Because with studded tires the studs are
going to abuse the hell out of the rollers if the rollers get caught
between the studs and the pavement. They may just rip the cable that the
rollers are stung on (bead-necklace style) or tear the cable out of its
crimped end.

>> I think older tire technology had much more aggressive tread blocks than 
today's modern snow tire and that is what is bad news for this combination.  I 
also think the cable chain company is covering their butt by telling you to 
not use them on "snow" tires.  Today's modern snow tires have rounder shoulders 
and grooves that don't seem as deep as an "off road" snow tire.

This is getting way to deep.  I am by no means as experienced with cable 
chains as you guys that live in snow country probably are.  I have had limited use 
with them on my car.  I do tend to over analyze things, but like to 
understand how things work.  Just use common sense, check your cables frequently while 
driving, don't exceed the chain's suggested speed and drive within the 
conditions/surroundings.<<

-Dick-
78 Scirocco
Original Owner
http://members.aol.com/sailingfc/