I know everyone says this, I'd just like to know the reasoning/physics behind it.

Thanks

 

Smaller diameter wheels will usually have a larger sidewall. However, the main factor I think has to do with the width of the tire. The wider the tire, the less it will cut into the snow or ice. Thus, you will have less traction and you will spin your tires. Narrower tires cut into snow better and are able to achieve better traction.

 

with runners. The toboggan (wide tires) duesn't cut into the snow, it just rides and slides on top of it.

 

For the same outside diameter a small wheel will take a higher profile tire. There are two advantages - the tall skinny tire can give a higher point pressure on the contact patch, cutting through the snow, rain, slush, also, there's more flex to accomodate the softer irregularities of the snow (it's a lot softer than pavement). A side benefit is that higher profile tires are more forgiving in handling making the car more comfortable to drive in slippery conditions.

Dave

 

well think of it this way..is it easier to shovel a path 1 ft wide or would it be easier top shovel a path 3ft wide? the narrow tire is the 1ft and a wide tire is 3ft. the tire can dig better. a lot of people think that a SUV w/ WIDE tires are better for the snow...well it's betten because most SUV have 4WD. but in deep snow the snow will clog up the threads of the tire and the tire will end up riding on top of the snow instead of gripping the road.
Dan

 

I've got it now. Thanks everyone

 

In a word, the smaller tire has more pressure/weight on each square inch. The weight on a wider tire is dispersed more.

 

I need to figure out how to fit bicycle tires/rims on my car. Anyone done this mod yet?

 

NO ... but I went and grabbed some PIE Plates, and dropped em on my Max!!!!!

 

Ya... something that most people intuitively get wrong, is thinking that a larger surface area results in more friction..

it does not... Just something you learn in a 1-rst year physics course.. As for the comments about the pressure/inch, they are absolutely correct..

Think of nails... the thinner the nail, the easier it is to get it into a wall (neglecting things such as bending, etc.). Why? because you are concentrating the force on a smaller point.. Same thing with a knife.. A sharper knife (read : thinner edge), cuts better than a dull knife (read : wider edge)..


Snow tires, and tires specifically designed for slippery conditions (ie. rain), are something totally different [conceptually at least], and rely on intelligent thread design in order to maximize your traction in perilous conditions!!

 

Everyone seems to have answered (correctly) why the width (track) of the tire should be narrower.

However, the question was regarding the diameter of the wheels. With smaller diameter wheels, there is a much larger tire profile, and therefore more flex to the tires. To improve you grip on snow and ice, you want the tire to be as flexible as possible, in order to improve contact and grip.

BTW - we had a major blizzard last night, and my new Blizzaks on 15" wheels performed flawlessly in getting me to work today.

 

Love this, so drammatic!