Just installed my winter tires ... Look at the difference!
 

Here's the 20" Diamaris compared to the 18" Pirelli Scorpions. The truck is so much smoother and easy to turn, it almost feels like a minivan after taking off those 20's. :rofl:

Of course the handling isn't nearly that great and they look rather puny but hey we've already had light snow this week and I don't want to take any chances...:nervous:

Did the same thing as we had a light snow last week as well. It's amazing the difference in size!! Took the 20's in already for a balance that way they are ready to go next spring.

I've always use my 22 even when it snows although it ruins the lip but i polish it when spring comes, should i change? i mean i feel no diff than using my 19

I have 18 with regular michellin (spl?) tires.

Should I get snow tires? I just want to get out of my house which is 1/4 mile long private driveway. Sometimes it snows 4-8 inches.

,

How much did those snow tires run you?

It depends on where you live and snow conditions there. You will notice big difference in driving on snow if you have dedicated snow tires as compared to performace tires for summer. You don't want to take chances sliding with 22s on snow.

The 18" look somewhat deformed? One edge looked smaller than the other...or is that just the camera lense playing tricks on the eye? The 20", on the other hand, looks fine :dunno:

narrow tires grip snow better and increase traction (wgt/sq in) - where you want the tire to grab more snow for traction (deep grooves) and push down thru the water to bare pavement to minimize hydroplaning - mine are on 18" rims - safety before vanity

That used to be more true than it is today. Older generations of snow tires relied primarily on the tread blocks on the edge (shoulder) for all of their traction. More recent designs use modern rubber compounds and much more sophisticated tread patterns to grip over the whole width of the tire. That is why we are seeing performance snow tires in these sizes.

You can't push down any more with a wide tire or a narrow tire. The narrow tire does have a shorter path for water to get squeezed out, reducing hydroplaning' as you say. However, since the truck weighs the same (lb) and the tire pressure is for all intents equal (lb/sq in) you will have the same contact area (sq in) whether you have a wide tire or a narrow one. All that will change is the shape of the contact patch, not the size of it (disregarding the effects of the sidewall stiffness).

Wow compared to the 18's those 20's look as wide as Viper tires

This can't be right. The whole idea of a wider wheel is to increase the size of the contact patch therefore increasing traction, whether it be cornering, braking or accelerating, the wide wheel will always out perform the narrower wheel. Except in very wet/snowy conditions were the increased width can work against you.

Don

Yes, it must be a reson why rally drivers use narrower tires on snow than on tarmak.

Well, it is right. The wider wheel simply can't have a bigger contact patch area, unless you lower the tire pressure or increase the vehicle weight. What the wide wheel does have is a different shape for the contact patch, wider (and shorter around the tire circumference) than the narrow wheel.

To increase the contact patch area, look to off road drivers in sand, or drag racers with very soft slicks. Very low pressures, with resulting larger contact patch areas.

The wide tire won't have any more traction than the narrow tire, if all other things are equal. Fortunately, all other things are not equal. The wider tire will usually have a softer compound, or multiple compounds. Soft compounds cause faster wear, and give more traction. The wide tire will also have a shorter sidewall, which will flex less, meaning that steering inputs are transmitted more directly, resulting in more precise handling. This is without considering all of the science around friction related to deformation of the tire at the contact patch, which is related to the shape of the contact patch.

Why not just put a soft compound on a tall tire? Because it won't last, the sidewall flex will lead to early failure.

With snow tires, the wider tire, having a wider contact patch (of the same area), has less of the rim circumference on the contact patch. That means that not as many traction lugs on the edge of the tire, which traditional snow tires relied on, are engaged at the same time (there are fewer on the ground at any moment). That is where the common understanding that snow tires should be narrow comes from. There is a reason for it, it just doesn't have anything to do with pushing down more into the snow.

Modern snow tires with winter rubber compounds are designed to get traction at all of the sipes on the tire, not just from the lugs around the shoulder of the tire. That is why it is less critical now to have narrower tires. It does still help, but if you think back 5 or 10 years, there was no such thing as an 18" snow tire. There are lots available now.

Interesting subject. Tire design is moving very quickly, much more quickly than vehicle design.

Jeff

We should also remember that cars are getting bigger and bigger tires as standard and as an option you can have 1" or 2" bigger and then usually also wider tires. So, as car manufacturers are increasing the tire size tire manufacturers has to follow and provide options also to winter tires. Sure, tire technology has improved a lot in 10 years, but still you should remember that where man can't walk he is able to ski over, the wider tires the easier car starts sliding on snow instead of getting grip on road through the snow.

Snow tires don't grip the road, they grip the snow, if there is in fact snow under the tire.

Jeff, ok I understand where you are coming from now, however, regardless of tyre advancement, a narrower tyre will always be better in snow and this is simple because the narrower the tyre, the greater the weight per square inch and therefore the more the tyre will dig in to the snow. What we should also remember is that the x-drive will also do a lot to help keep the car moving regardless of the width of tyre, but having a more suitable tyre for the conditions will always be an advantage.

Don

I tried to explain why this isn't true, above. See my previous posts. Perhaps another poster could chime in with a clearer explanation. Put simply, the pressure is the same on the inside of the tire and the outside. If you are running 32 psi, that is the ground pressure.

I do agree that narrower tires are often better in snow, even with recent tire advancements, but it doesn't have to do with pressure and pressing down through the snow. It has to do with a long and narrow contact patch, which results in having more lugs along the edge of the contact patch, engaging the snow. There is also a shorter front edge to the contact patch, and along that front edge the tire is plowing snow. A narrower tire therefore has to plow less snow, which results in less rolling resistance in deep snow.

A narrower snow tire won't always be better than a wider tire, because tires use different compounds and different designs of traction lugs, but it has some design advantages on its side.

Maybe we should go back to the ski analogy that another poster used. For the same person, with the same weight, and the same ski (thereby having the same ground pressure) does it sink in more or less if you turn it sideways (ignoring the effects of the edges for a moment)? No difference. Wide tires have a contact patch like a sideways ski. Narrow tires have a contact patch like a ski pointing straight ahead.

Anyone else want to take a shot at it?

Jeff,
That explains the diff, in a nutshell, imo. :thumbup:
Br,mD

I run the exact same setup! You do notice a huge difference in ride comfort but you lose a ton of traction.