Adding weight to a vehicle

“a lady who was a fellow teacher made this comment in the teacher’s room. I heard you guys talking about adding weight to the back of your trucks so I tried it in my car. It didn’t help at all. It was terrible. After a little questioning, we found out she had all season tires and…fwd.”

I think that I may have encountered her cousin several decades ago.
After a very heavy snow storm, as I was walking to a grocery store, I saw a woman who was throwing traction grit under the rear tires of her new-ish Toronado, which was in the middle of a large snow drift.

Thinking that I was being helpful, I stopped to point out to her that, if she was having traction problems, she should be throwing the traction grit under the front tires. Her angry response was, “Listen sonny, those front wheels are turning just fine. It’s the rear wheels that I can’t get to move!”

I said something along the lines of…Of course…How silly of me…and continued on my walk to the grocery store.

The bad thing about adding weight behind the rear axle is that it destabilizes a vehicle causing oversteer. You might be able to mitigate this by slightly underinflating the front tires and slightly overinflating the rear tires.
Make a vehicle tail heavy enough and it starts having the handling charactoristics of a taxiing taildragger airplane, these are infamous for ground looping and being a handful to keep going straight at high taxiing speeds. This is because the center of mass is behind the main wheels and the g-forces of a turn acting on the center of mass causes the turn to become tighter and can go to the point of no return, a ground loop, which often causes a wingtip to scrape the runway.

I made it through a couple of Alaskan winters with a 2WD Jeep pickup by adding weight to my bed. I put a large plastic sheet in the bed of the pickup when freezing weather arrived. I filled up the bed with water and let it sit overnight to freeze. I trimmed the plastic sheet and was good to go. Fuel economy plummeted but the truck handled very well on the frozen Alaskan highways…as long as you drove slowly. You could always tell who drove fast because you could see them in the ditches on the right and the left…usually facing the wrong direction.

I believe there are just too many factors to expect a rule of thumb to provide a reliable answer to this one.

There are many factors.

I have to ask how many of those asking have winter tyres on their car?

@VDC
That’s hilarious !
@joe
You are absolutely right about the variables. But generally speaking, if adding weight balances the distribution in a rwd4wd car or truck, and is done correctly , there is no down side. That is not to say you throw 500 lbs in the back of a delicately suspended BMW and leave it all winter.
But , one thing must be noted. Adding weight anywhere to a fwd car, other then on the front seat as you back up a slippery steep hill, does nothing to help and often hurts traction.