My daily commuter is a rear-wheel drive car. Living in the Midwest, I have always hauled around two or three 80 lb. salt bags in the trunk in case I encounter snowy/icy roads. Like many others, I have always believed that the weight would improve traction.
But then I got to thinking… is this a smart thing to do? While I would think the extra weight would improve traction when stuck, wouldn’t it also increase the momentum of the vehicle, thus making it more difficult to stop after applying the brakes?
So here’s my question: Does the positive aspect of extra weight in the trunk (i.e. more traction) cancel out its negative aspect (i.e. more momentum)? Should I not put the salt bags in the trunk this year?
Since I live in sunny California and have never driven on snowy/icy roads you should take the following with a grain of salt (which you apparantly have plenty of).
I don’t think I’d worry about the additional momentum when braking. The salt is the equivalent of having maybe two extra people in the car. And if it enhances traction when starting out it should also enhance traction when braking. That said, my best guess is that, unless your car has hardly any weight on the rear wheels, you would not be able to tell the difference between having the extra weight or not having it. If I were you I’d be inclined to find a patch of ice and do the experiment to find out for myself. You’d probably see much more difference in traction between regular and winter tires.
Get rid of the salt bags and replace them with kitty litter.
If you plan to use the salt if you get stuck, forget it. It takes time to work and often works best at, near or above freezing. There is also a strong possibility the bags could leak causing corrosion from within your vehicle. This is made worse if relative humidity levels climb.
OTOH, coarse kitty litter not only adds weight, but is very good at recovering traction if you get stuck. Even so, put a coal shovel in the trunk, too, so you can dig out just that much easier before you scatter the kitty litter and attempt to move.
I’m from the MidWest originally and I used to do it every winter.
You’re neglecting the weight’s contribution to dynamic friction. With more weight on the tires, you can turn harder and accelerate more quickly without breaking traction. That’s really important when driving on ice.
The added momentum will make it take longer for you to stop completely on ice, but one of the tricks of driving safely in winter is to try to avoid making any sudden changes to your velocity or direction of travel. Since glare ice might not let you stop in time anyway, it’s nice to have the little extra maneuverability that sandbags can give you.
If you feel the need to prove this to yourself, spend an icy morning cutting kitties in the church parking lot, with and without sandbags. You should notice a difference.
It depends on how your car is balenced. By putting suck weight way back you are shifting the car’s center of gravity causing more of the weight on the rear wheels (possibly more then the bags weigh if you place them behind the wheels). The transfer of weight could make a significant difference. I knew someone who moved their battery to the rear for just this reason (and had a bitch of a time getting the wires for it)
Also I would also say that cat litter(non clumping) or sand would be better then salt.
Whenever we get calls for ice/snow, as we did last week, I load up a 55 gallon drum in the back of my truck, and fill it with water. It seems to help rear traction, and I haven’t noticed any difficulty in stopping, but I have noticed, with the center of gravity shifted, the front end gets a bit squirrely. As a slight hijack, does anybody know if overloading the rear end decreases traction in the front?