the ice being an object like a rock has its own friction setting which is set pretty low to make you feel like you are on ice, however much like real life lots of factors will change how drastically your vehicle is effected. ie your speed on the ice, how much you are turning, what gear you are in ect.

Friction level of the tires not really the size can effect the most of whether you slide all around or just a little for example if the friction is lower on the tires you will have less grip and and if the friction is higher you will have more, higher friction on tires as on any of banks performance trucks will cause you too slip slightly where as with one of say spun or nix trucks you will slide a bit more.

As for size of the trucks i would imagine you get more grip with a bigger heavier truck although you would obviously have a harder time stopping with it but more control as it wouldnt be spinning the tires as quickly(not real life experienced in big trucks on ice.)

If you head out to the 2 lumber mills right by each other you will find a large frozen area or to the other lumbermill and behind it where a mud pit once was, i would suggest using one of those areas to get a feel for how the ice effects different vehicles as i have ony really been using my own vehicle in the ice testing.

also there are other maps with ice and snow some better than mine, the only difference will be in that my snow textures for the ground are from a friend of mine and nobody else has those

Very interesting, thank you for the reply, and information!

no problem thanks for checking out the map