Wide or Narrow Winter Tires

[RedTacoma]

The key to ice/snow traction on the road is increasing ground pressure.

Skinny tires put more ground pressure on the pavement/ice. The limitation on traction is more limited by the ice than the contact patch. On dry pavement the larger contact patch of a wider tire is useful.. On icy/snowy pavement your traction actually goes down with less ground pressure.

BTW Rubber doesn't stick to ice/snow. Snow/ice stick to snow/ice, hence why snow tires are siped to retain a little bit of snow in the tread... Acts like glue.

If your logic of wider tires made sense... My Dually plow truck would be better in the snow than my cruiser with skinnies... Its not... Unless I put 8000lbs of concrete on the bed. And I do. We receive 200+ inches of snow a year... it has snowed a foot on July 4...

You are comparing two different vehicles, I have two tire sets for my cruiser and I have to deal with Ice daily for few months out of the year. Thread on both tire sets is the same so only difference is how wide they are. On skinny tires not only my locked truck have problems climbing the hills it can simply slide down the hill with alll 4 wheels locked. On the same hill with wider tires truck has no problems and in one occasion was going up the hill, and was pulling minivan behind it. Road had 2.5 - 3.5 inch thick ice cover. (My personal Ice Road)
I Dont know why people keep repeating the same stuff.
People read forums and on the snow run, you find some dude that shows up with skinny tires and gets stuck every two feet. And thats if he is lucky if not he will have to replace half of the body panels when all said and done. Skinny tires + studs yes, Skinny tires on its own hell no. Its physics. If you put enough pressure on ice, top layer melts turns to water and you slide. Wider tires = less pressure and top layer stays nice and frozen.

 

[80t0ylc]

.....BTW Rubber doesn't stick to ice/snow. Snow/ice stick to snow/ice, hence why snow tires are siped to retain a little bit of snow in the tread... Acts like glue.........

Who told you that? Tire siping is not limited to just improving snow driving. It adds more "cutting edges" to the larger lugged surfaces of tires and allows them to be more flexible. Google tire siping and read for yourself.

 

[chtucker]

You are comparing two different vehicles, I have two tire sets for my cruiser and I have to deal with Ice daily for few months out of the year. Thread on both tire sets is the same so only difference is how wide they are. On skinny tires not only my locked truck have problems climbing the hills it can simply slide down the hill with alll 4 wheels locked. On the same hill with wider tires truck has no problems and in one occasion was going up the hill, and was pulling minivan behind it. Road had 2.5 - 3.5 inch thick ice cover. (My personal Ice Road)
I Dont know why people keep repeating the same stuff.
People read forums and on the snow run, you find some dude that shows up with skinny tires and gets stuck every two feet. And thats if he is lucky if not he will have to replace half of the body panels when all said and done. Skinny tires + studs yes, Skinny tires on its own hell no. Its physics. If you put enough pressure on ice, top layer melts turns to water and you slide. Wider tires = less pressure and top layer stays nice and frozen.

I don't take my information from forums. I live at 10,000 feet. I have snow in my yard from October till Memorial day. It has snowed 12" on July 4th. My job entails towing 10,000 lbs of sno-cat around all winter... Only real world experience.. Michelin Ice driving school, and a little bit of ice racing to keep my skills sharp and a few Mechanical Engineers on staff who spec out our fleet... Btw below is a sample of what I do... and the sno cat picture was taken on June 4th, 2008. Not many places have that much snow in June...

 

[chtucker]

Hey and Transport Canada agrees:

http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/4h5776/$FILE/CDM_SnowTires.pdf

Wide tires are much better suited for summer driving, so look for narrow and compact styles to get you through winter season. Narrow tires have much better traction for slippery roads, and you reduce the chances of getting stuck!

 

[RedTacoma]

I don't take my information from forums. I live at 10,000 feet. I have snow in my yard from October till Memorial day. It has snowed 12" on July 4th. My job entails towing 10,000 lbs of sno-cat around all winter... Only real world experience.. Michelin Ice driving school, and a little bit of ice racing to keep my skills sharp and a few Mechanical Engineers on staff who spec out our fleet... Btw below is a sample of what I do... and the sno cat picture was taken on June 4th, 2008. Not many places have that much snow in June...

Huh, You are driving snow cat on tracks (device designed for increasing surface contact area)
I would like to see picture of snow cat on four, 1 inch steel circles. After all, that would be the ultimate skinny wheel isn't?

I mean look if skinner was so much better all of us would come on the snow runs with bicycle tires on cruisers. Oh yea Ultimate skinny

Me I gonna stick to what I had learned for many years driving in some of the worst places on the planet. Wide tires always worked better for me, just as apparently wider works better for people from Iceland to Siberia.

 

[coax]

I wish I could find the article I read about this a few years back that tried to dive into the physics of narrow vs. wide in the snow.

Going from memory, there were a few major points, first being the type of surface driven on: deformable or non-deformable. Non would be ice, extreme hardpack, etc where the weight of the vehicle doesnt "deform" the driving surface. In cases where the surface is deformable, a narrow tire provides more traction/friction/etc due to the greater pressure deforming the snow.

Second point was stating that force due to friction is made up of the weight of the vehicle (normal force) and the coefficient of friction between the tires and the snow/ice/whatever. The surface area of tire on snow comes into effect for when the tires start to slip (static friction vs. dynamic friction). In this case the more surface area of contact, the harder is to move from static (not sliding off the road) to dynamic (sliding).

That being said (and greatly over simplified and butchered), I agree w/ previous posts that the type of tire (AT vs MT), softer rubber, siping, etc probably have a much greater effect. Especially when its 4cm of width in either direction. If you've got chains for once size of tire, I'd personally go that route.

FWIW
Corey

 

[80t0ylc]

Huh, You are driving snow cat on tracks (device designed for increasing surface contact area)
I would like to see picture of snow cat on four, 1 inch steel circles. After all, that would be the ultimate skinny wheel isn't?

I mean look if skinner was so much better all of us would come on the snow runs with bicycle tires on cruisers. Oh yea Ultimate skinny

Me I gonna stick to what I had learned for many years driving in some of the worst places on the planet. Wide tires always worked better for me, just as apparently wider works better for people from Iceland to Siberia.

I've been reading your posts and I just have to say, you are wrong about your understanding with the application of wide tires and traction in snow. Yes, snow cats run on wide tracks and snowmobiles have a wide single track. But it's for flotation more than traction. It is no comparison to what DD requirements are for running in snow. You're comparing apples and oranges. Snow machines have to stay on top of the snow for traction - not dig in. In snow sometimes 15 and 20 feet deep or more. And usually the top layer of that is powder. Your experiences that you've mentioned on ice are just a part of winter driving. On glare ice, very few things will help. Chains and studs do until you break traction and then they're actually worse because they have minimized the contact with the surface to their sharp points which are now sliding like ice skates. The best advice for winter driving, because so much of it is on packed snow/glare ice, is to avoid the deadly combo :
1. slippery surface like water, ice or packed snow;
2. speed or momentum;
3. sudden change of that speed/momentum or direction of travel.
Because loss of control is the outcome when these 3 are combined. Successful winter driving is accomplished by proper management of this 3 sided triangle. We don't have much control over 1 unless we have alternate routes available. But, 2 and 3 are within our reach to control. And we can augment that by having proper tires and as many driving or powered wheels as possible, such as our 80 series (in working order). BTW, where do you live now and maybe you can elaborate on this:

.....Me I gonna stick to what I had learned for many years driving in some of the worst places on the planet......

This ought to be interesting.

 

[RedTacoma]

I've been reading your posts and I just have to say, you are wrong about your understanding with the application of wide tires and traction in snow. Yes, snow cats run on wide tracks and snowmobiles have a wide single track. But it's for flotation more than traction. It is no comparison to what DD requirements are for running in snow. You're comparing apples and oranges. Snow machines have to stay on top of the snow for traction - not dig in. In snow sometimes 15 and 20 feet deep or more. And usually the top layer of that is powder. Your experiences that you've mentioned on ice are just a part of winter driving. On glare ice, very few things will help. Chains and studs do until you break traction and then they're actually worse because they have minimized the contact with the surface to their sharp points which are now sliding like ice skates. The best advice for winter driving, because so much of it is on packed snow/glare ice, is to avoid the deadly combo :
1. slippery surface like water, ice or packed snow;
2. speed or momentum;
3. sudden change of that speed/momentum or direction of travel.
Because loss of control is the outcome when these 3 are combined. Successful winter driving is accomplished by proper management of this 3 sided triangle. We don't have much control over 1 unless we have alternate routes available. But, 2 and 3 are within our reach to control. And we can augment that by having proper tires and as many driving or powered wheels as possible, such as our 80 series (in working order). BTW, where do you live now and maybe you can elaborate on this:



This ought to be interesting.

ah not a issue lets agree that people should drive what works for them

 

[Bearcat80]

ah not a issue lets agree that people should drive what works for them

What he said.


Snow conditions vary so much from place to place and even within the same stretch of road that to offer advice generically is stoopid. Buy good dedicated ice and snow tires. It won't matter nearly as much how wide as how good they are. A more educational thread might be which brand of snow tire.

 

[jasonmt]

Hey and Transport Canada agrees:

http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/4h5776/$FILE/CDM_SnowTires.pdf

I am lost on how you take a 1 page .pdf file with the title: "AB 4-H Consumer Decision Making Study Guide, Snow Tires" and attribute it to Transport Canada?

But apparently someone who belongs to a Alberta 4-H club agrees with you.

 

[Ebag333]

I am lost on how you take a 1 page .pdf file with the title: "AB 4-H Consumer Decision Making Study Guide, Snow Tires" and attribute it to Transport Canada?

But apparently someone who belongs to a Alberta 4-H club agrees with you.

Is this in depth enough for you?

http://www.crrel.usace.army.mil/library/technicalreports/TR-01-16.pdf

Or is the US Army not good enough for ya?

 

[CreeperSleeper]

Holy crap, guys... I don't think it really matters if you know how to drive in the conditions that you are driving in. I will be driving in the ice with my non-siped, 14.5" wide bias tires. Deal with it.

 

[jasonmt]

Is this in depth enough for you?

http://www.crrel.usace.army.mil/library/technicalreports/TR-01-16.pdf

Or is the US Army not good enough for ya?

Where was I commenting on the comprehensiveness of the link?; just curious how someone links a Alberta 4-H club "document" and then attributes that "document" to Transport Canada.

Notice how you said "US Army" and linked to a US Army document

 

[ERG80]

Was this the article?
Expeditions West: Tire Selection for Expedition Travel

I wish I could find the article I read about this a few years back that tried to dive into the physics of narrow vs. wide in the snow.

Going from memory, there were a few major points, first being the type of surface driven on: deformable or non-deformable. Non would be ice, extreme hardpack, etc where the weight of the vehicle doesnt "deform" the driving surface. In cases where the surface is deformable, a narrow tire provides more traction/friction/etc due to the greater pressure deforming the snow.

Second point was stating that force due to friction is made up of the weight of the vehicle (normal force) and the coefficient of friction between the tires and the snow/ice/whatever. The surface area of tire on snow comes into effect for when the tires start to slip (static friction vs. dynamic friction). In this case the more surface area of contact, the harder is to move from static (not sliding off the road) to dynamic (sliding).

That being said (and greatly over simplified and butchered), I agree w/ previous posts that the type of tire (AT vs MT), softer rubber, siping, etc probably have a much greater effect. Especially when its 4cm of width in either direction. If you've got chains for once size of tire, I'd personally go that route.

FWIW
Corey

 

[chtucker]

I think the only real solution to this is MYTHBUSTERS....

Anybody want to write them?

 

[Snakeshot]

I daily drive snow and ice every winter.

I commute down a 12% grade in a deep canyon that sees zero sun for two months. I call it the "Icebox". I have done every kind of bad road ballet imagineable, and in various all wheel drive vehicles. Every type of compacted snow and thaw/freeze/evil ice you can imagine.

Skinny snow tires rule.
Skinny snow tires with studs rule even better.

And going uphill is rarely a problem here...

...but nothing works for everything, and ultimately it comes down to the operator.

 

[RedTacoma]

Is this in depth enough for you?

http://www.crrel.usace.army.mil/library/technicalreports/TR-01-16.pdf

Or is the US Army not good enough for ya?

That is very interesting document... Excellent and now bookmarked

 

[maybe_a_80...]

Okay, I've read allot of treads but here's the breakdown of what I'm looking at. The wife authorized a set of winter tires (I know I'm starting early). These tires will be spending the offseason on my trailer and as spares for the truck and trailer, so they have to match the size I'm running (255/85 KM2). I've narrowed the field down to two options, General AT2 295/75R16 and Copper ST 255/85R16. I've heard great things about the AT2s, but I have chains that fit 255/85. So in the end it comes down to which is better wide or narrow, and as I don't know snow and ice all that well I thought I'd get some input. Let the posts begin. Thanks.

Some more input:

Tire Width:

As a former ski industry drive-a-holic, I have extensive mileage on a number of different sets of tires in winter weather. The most recent comparison was my last industry vehicle, a 2008 GMC Sierra 1/2 ton, 8 ft bed. I equipped this truck with Goodyear Wrangler SilentArmor 235/85/16s. It was amazing to drive snowy roads across the West, the truck was never deflected by changing snow depth on the road. It was an ultimate set-up. When I purchased my 80, it had 275/70/16s on it, and driving to and from work between SLC and Park City last winter, the 80 deflected all over the road from changing snow depth in the driving lanes. I did not feel particluarly safe and had to watch my driving more than I care to in snow. Narrower tires ARE easier to manage in snow for on-road use applications.

In the case of a 255/85/16 compared to say a 295/75/16, some of the "lost friction" due to the narrower width is made up with the length of the contact patch - it is re-allocated lengthwise instead of widthwise.

If more proof is needed of narrow tread width superiority for road use, look at what Rally race cars run for snow stages: narrow tires.

I will happily throw all this logic out the door when it comes to driving off-road in the winter (actually if that was the discussion I would have no useful input).

Tread Patterns/Rubber Compounds:

M/T tread patterns are not as effective for DD use in snow (for all of us in the lower 48) because the tread pattern is too chunky and does not conform well (does not have enough "biting edges") in cold temps to the road. As has been mentioned before, siping is a huge help when driving on icy and snowy roads. For proof, look at the amount of siping on any true "snow tire". A great example of this is the Cooper Discoverer M+S snow tire compared to the BFG M/T tire.

Rubber compound can also play a role. True snow tires have silica compound in them that helps the tire to remain more compliant (and therefore more conforming to the road) in cold temps. Again, a M/T (and most A/Ts) fail in comparison with true snow tires in regards to silica content. Compound is a huge conundrum for all of us on this site as tread compound plays such a small role in nearly all of the tires we all consider, so it's not worth getting into too far.

Recommendation:

Having run narrow and wider (not super wide) tires in snow, I am planning to purchase the Discoverer S/Ts in 255/85 this fall as my DD tire for year-round use. According to Pearson Tire Distributors in SLC, UT, the S/T in 255/85 is the most popular tire in the Wyoming gas fields, and they send a truckload of tires to western Wyoming every week. I think that says a lot about the tire's winter capability. I will most likely get my S/Ts siped in addition as the S/T tread pattern is a little too M/T oriented for my taste; the siping will increase the tire's ice performance by increasing the effective number of biting edges (to simulate true snow tire tech). The center siping of the tire will help it track really well in snow, and allow slush somewhere to go other than between the tire and the road. I know I have trashed M/T tread patterns for snow and am getting something M/Tish, and this is because I want 33s on the truck but want them narrow based on how 275s drive in deep snow at highway speed (not so confidence inspiring).

I AM interested in how Goodyear's new Duratrac in a 285/75 would perform compared to the Cooper Discoverer S/T 255/85 for on-road DD winter use. I think these two tires are the best options right now for winter use. A close third is Goodyear's Wrangler SilentArmor. So, if you want to look at an option other than the S/Ts, check out the Goodyear tires, not the General Grabbers. There are those that feel the Goodyears has weak sidewalls; pony up and the E-load rated version and there's no issue, especially not in a 5,000lb 80.

Excuse the long post...