Join Date: Jan 2002
Location: Kelowna, BC, Canada
Thanked 0 Times in 0 Posts
Re: Mud tires in the snow...is this bad?
ok folks - no big secret, I run the ice roads up North as winter trek runs...so here's my $0.02
BVM - you're partially right. on deep snow (18"+), wide, and float is good. as has been mentioned, its very much like sand..but more so ( you dont often see sand runners go 3 feet down into the sand - I've seen quite a few trucks do that in snow) for the record, ruber will not stick to snow..snow tires are designed to grip a certain amount of snow in the treads, then they stick that snow to the ground to generate traction. self cleaning defeats this entirely, which is why mud tires generally make lousy on-road winter tires.
For ice, and roads where you get a thin ( <12") skim of snow over a hard surface, the 'limit' is when your braking power exceeds your vehicles weight. by that, I mean that your vehicle does not put enough weight down to allow you to use the brakes. in the Niva ( 2600lbs stock) anything over 235's is the pits on ice because my weight per square inch is so low. its a friction thing - apply 1 lb /square inch pressure to a sheet of sandpaper, and try an move it across a sheet of steel..pretty easy. now try it with 10 lbs per square inch...much harder. the lighter footed the rig, the closer you get to scenario 'a', which, in real world terms is when you lock up the tires, rather than slowing the vehicle. the narrower the tire, the higher the weight per square inch, and the more you can do with teh available traction. ( note that distinction - sometimes, there simply ISNT traction for rubber tires)
sipes, studs, chains, funky compunds with crushed walnut shells in it, playing ith tire pressures..all are attempts at creating more friction for handling / acceleration / braking. for what I do, skinnys ( 235/85R16's, or even older 7.50*16's) w/ sipes, and studs, augmented by chains for really bad conditions seem to be the trick - but studs, and chains arent legal everywhere, and are annoying if you have to keep putting them on / off.