Tire Pressure and Snow

[Brandon002]

Originally Posted by Helihover

You have now confirmed that we are on different intellect levels.

Safe driving.

Apparently we are, considering you don't understand the difference between compression and friction.

I suppose diamonds are made out of coal under friction as well.


Tell me this. What works better? A tire that cuts through the snow and reaches pavement? Or a tire that grabs a hole heap of snow while remaining on top of the snow?

[JCL]

Brandon:

You continue to confuse the various types of friction.

Older snow tires, and snowmobile belts for that matter (since you mention them) work in a particular way. They work by having a deep lug around the shoulder of the tire that digs in. As long as the lug can dig in (whether it is on the edge of an old-tech snow tire) or across the belt of a snowmobile, it will provide traction. This is where the old maxim about using narrower tires in snow comes from. Raising the inflation pressure on this design of tire will provide a cleaner should edge that grips better.

Modern winter tires have sipes all across the tread. They don't dig in in the same manner, rather all of the sipes provide traction. This is also the concept behind ice tires. These tires are not designed to sink in, but rather stay on top. And they work very well. Years back, there was no effective 20" automotive winter tire, they simply didn't exist. Today, we have performance winter tires in sizes such as the X5 sport package uses, and they in fact work better than the old tech snow tires. Overinflating these tires will reduce their winter performance.

If you are so convinced that narrower is better, without considering tread compounds and tread patterns, put an old narrow snow tire up against a modern performance winter tire and see which works better. You may be surprised.

[giodog2000]

I couldn't imagine driving with my 315 rear setup as they would float over the snow all the time. Even if I ran it at 10psi, it wouldn't be as good as a narrow tire right? So we all agree narrow is better in this case. In mud for example, we want the exact opposite cause we want to float rather than sink. I can see a certain logic to inflate so that the tire stays narrower. As an Enduro rider , we deflate because we want the tire to FLEX over uneven structure so that it can grab whatever it can and create GRIP. There is not much to grip on cold asphalt so I don't really see the need to deflate lower than the recomended psi.

[JCL]

Originally Posted by puddinboo

now I`m comparing sav tires to bike tires lol, I know for a fact that the skinny bike tires have more traction in snow than the wide mountain bike tires because the skinny tires are touching less ice equals more traction, touching more ice equal less traction, hope this makes sense took me awhile to figure it out ,then it just clicked.

That is only true if the narrow bicycle tire can cut through all the way to clean pavement, and the wider bicycle tire can't. If you are in deeper snow that packs and can't cut through, the wider bicycle tire with deep lugs and low pressure will do better.

[JCL]

Originally Posted by giodog2000

I couldn't imagine driving with my 315 rear setup as they would float over the snow all the time. Even if I ran it at 10psi, it wouldn't be as good as a narrow tire right? So we all agree narrow is better in this case. In mud for example, we want the exact opposite cause we want to float rather than sink.
I can see a certain logic to inflate so that the tire stays narrower. As an Enduro rider , we deflate because we want the tire to FLEX over uneven structure so that it can grab whatever it can and create GRIP. There is not much to grip on cold asphalt so I don't really see the need to deflate lower than the recomended psi.

No, your 315 summer performance setup will not perform at any pressure.

But if you had a winter tire compound and tread pattern, you could get good performance in wide profiles. Narrower is not always better, it depends on how the tire is designed to provide traction.

[giodog2000]

Originally Posted by JCL

No, your 315 summer performance setup will not perform at any pressure.

But if you had a winter tire compound and tread pattern, you could get good performance in wide profiles. Narrower is not always better, it depends on how the tire is designed to provide traction.

I was referring to 315 winters for comparison. ( lol I know my summers would;t work that well no matter the size )

[giodog2000]

Originally Posted by JCL

Brandon:


If you are so convinced that narrower is better, without considering tread compounds and tread patterns, put an old narrow snow tire up against a modern performance winter tire and see which works better. You may be surprised.

He doesn't need to do that. He is comparing different tire pressure with the SAME tire. Apples with apples.

[JCL]

Originally Posted by giodog2000

He doesn't need to do that. He is comparing different tire pressure with the SAME tire. Apples with apples.

He is relying on a traditional rule of thumb that says narrower is better. If he has a tire that drives primarily from the shoulder, with a square edge, he is likely right.

If he had a modern high performance winter tire that was not designed to drive primarily from the shoulder blocks, increasing the pressure would not make sense.

Two designs of winter tires shown, to illustrate the point. The mud and snow tire is the same technology I used to use on my Volvo, forty years ago. Narrow, cuts in, drives primarily from the shoulder. The centre blocks packed up on the first rotation. The Dunlop M3, by comparison, has round shoulders with no blocks there to cut in. The blocks across the tread are designed to eject packed snow. It would not make sense to overinflate these tires. And my Wintersport M3s significantly outperformed traditional designs, allowing a 535 rwd to go up hills that my X couldn't with lesser mud and snow tires.

[BMRSEB]

Originally Posted by Brandon002

I don't think I've ever seen a snowmobile with tires.

You know Meant an ATV, smarty!

[bcredliner]

Traction is much different that responsiveness and stability.

The article does not state winter tires should be inflated 3-5 lbs. more than recommended pressure for that winter tire. It reads that winter tires should be inflated 3-5 lbs. more that the recommended inflation of summer tires.

Nor does the article state the reason to do this is to increase traction. It says the 3-5 lbs. will improve responsiveness and stability--that is to say the extra inflation will result in less side to side tire role so steering input response is quicker and more predictable as will be response to braking pressure.

To improve traction reduce tire pressure.

The sticky wicket is that when the tire pressure is decreased the handling of the vehicle changes. If the pressure is lowered too much the vehicle will become dangerous to drive.

Even knowing decreasing the tire pressure improves traction, I have never chosen that route unless I was stuck and it was the last resort. A couple of pounds, maybe, but handling goes away so fast I really don't like doing that. If the tires don't provide the necessary traction either I should not be on the road or I need different tires.

As mentioned, rock climbers reduce the pressure for maximum traction for a difficult climb/drop. If possible, they would like to increase the tire pressure after they get past that section as they may have a fast section coming up where they will need responsiveness and stability rather than greater traction.