Severe Snow Symbol on an AT Tire

[skidaddy]

Well another tire thread. I’ve look around and I’ve seen some references but nothing that helps me understand why some AT (all terrain) tires have the Severe Snow Snowflake-on-the-Mountain designation and others don’t. I understand all AT’s by definition are M&S rated.There seem to be a few AT’s that have the Snowflake; BFG AT KO, General AT2, Pro Comp All Terrain, Dunlop RVXT. Most others; for instance the fairly new Yoko A/T-s do not. I’ve looked up the standard and other explanations. Howstuffworks "How Tires Work" they list an index of traction index of 110 (ASTM-1805); well all I can find is the standard A,B,C, DOT rating on the side of the tire. Can’t find that index number even for the ones with the Snowflake let alone the ones without. Got about a little more 4/32’s left on my 3rd set of Michelin MTX M/S (get about 45,000 miles) which was also the OEM tire 275/75/16 SR112 my cruiser came with. Wanted to replace before I hit the back country roads this summer.Looking to do something different, though I have had very good performance with these tires. The technology is now 15 years old. Only putting 4 to 5 thousand miles a year with ga$. 25% of time packed or up to 1 feet fresh powder snow (some ice). 25% summer mountain forest service roads to trail heads. The rest dry pavement getting to those places. So when I look at the Yoko AT-s they have a similar type design as the Snowflake AT’s and catalogue sheet indicates “Silica formulation” which normally gets better low temperature tire flex and is sometimes listed as ice / water friction enhancement. In addition it’s got the sipes and the pattern comparable to the Snowflake AT’s
http://www.yokohamatire.com/pdf/geoATS.pdfDoes anyone know if Severe Snow really means anything on AT tires?

 

[cary]

The AT-S is not a good snow tire, it lacks siping. If you read the background of that tire, you will see that it was designed for baja racing, and works very well as an A/T for everything but snow and ice (also see the mixed reviews on Tire Rack). I love Yokohama tires, but that is not the one for your needs.

For your wants, the Bridgestone Dueler A/T Revo sounds ideal. It is a more road orient A/T that still is more agressive and the stock tires, while providing great wet weather and snow and ice performance.

 

[mudking82]

Don't know if it will help you, but check out this article: Winter Tech - How to Confirm a Winter Performer

 

[skidaddy]

Thanks for the replies. The tirerack page did not show the Severe Snow AT tires I mentioned above with the rest of the Severe Snow so I called. The person I spoke to told me they go with industry product sheets where AT takes priority over “Winter” category. They do look at tires to see if the manufacturer has miscatagorized a tire. In the case of snowflake/mountain on the AT tires it was their opinion that even though technically it made the definition of a winter tire they did not list it that way. Anecdotally he felt none of the above AT snowflake tires handled that well in snow or ice to the “Winter” category. The one exception AT tire was the Revo (as mentioned in thread) which didn’t have the Snowflake/Mountain as Bridgestone had not submitted for testing. I asked if the traction index cold weather (ASTM-1805) was available on any tire and he said no, just the DOT A,B,C which is a warm weather standard.

So apparently the snowflake/mountain on an AT tires doesn’t mean much

 

[BooKilla]

I love the BFG AT's in the snow. They have plenty of siping and they release snow really well. The only thing I like more in the snow is blizzaks. MTC.

 

[skidaddy]

I love the BFG AT's in the snow. They have plenty of siping and they release snow really well. The only thing I like more in the snow is blizzaks. MTC.

How do the BFG AT's do on ice and water?

 

[smittycrusher]

Good Year Wrangler Silent Armor are "Severe Snowflake Rated" and in my experience have been great in all conditions. I have not had them in mud.....I know better. Snow, ice, rain, sand, rock hanve all been great. Going to get about 45K-50K miles out of them too.

Smit

 

[Fly Rod]

I have run BFG AT Ko's for the last 15 years on various rigs. I have never had an issue with them in the deep snow. This includes the two years that I worked at a ski area.

FWIW, I now have the Revo's on the 80 and would recomend them as a all around tire. I went up to cut a tree before christmas driving in 12" - 20" of fresh. At one point I hit ice under the snow and went strait at a corner. I ended up a little off camber in a slight ditch. All of this happened at <5 mph. Nothing I could do would get the truck to negotiate the turn so F/R/F/R/F/R until I climbed out of the rut. With the center locked, 7 pin mod, I was able to continue on. The Revos did the job in a situation that most other tires would have packed it in.

HTH.

 

[Atoyot1031]

I'm driving on studded MTs with a very aggresive pattern. The aggressive pattern helps with the snow and slop, while the studs do their job on the ice. It has worked out much better than I thought it would. I also didn't quailfy for regular snow tires as I wasn't willing to go smaller than 33s with 4.88s.

 

[skidaddy]

Thanks again for the replies. When using a Severe Snow one of the qualifications is the low temperature fiction of 110 (ASTM-1805) or greater even though the manufacturers will not tell us what it is by individual tire. I’ve read different things regarding performance on ice. Since it would appear that it is not the ice but micro layer of water between the ice and the tire that causes the lack of friction, does anyone have a preference on tire width for this purpose? For instance does a wider tire create enough float to keep from melting the ice or should I be more concerned with how the water is drained? I’ve also read a bias towards not going too wide for summer off road mountain driving.

Expeditions West: Tire Selection for Expedition Travel

 

[Atoyot1031]

The crazy dudes from Iceland run superwide tires on the snow & ice.

 

[Todo]

For what it's worth, according to what I was told at Les Schwab. The A/T, M+S, M/T, and all those abbreviations are not standardized. Toyo, BFG, Cooper, Michelin, all those guys may use for instance "A/T" but the tires may not be made with the same standards or for the same use. Don't know if the "Severe Snow" symbol falls into that category or not but thought I'd chip in what I did know.

My 80 needed tires and I was really worried about spending a lot of money on a tire that was just mediocre. It had Wild Country XTR 285/75/16's on the rig when I bought it and they gave me nothing but problems - they wandered real bad and they vibrated badly too (even after taking it to Schwab and having them check the balance and rotated). I have ran BFG A/T's in the past but you mention how your Michelin's use 15 year old technology, I looked at the BFG A/T's and kinda thought the same thing (yeah they got the KO series but it's still basically the same tire). I just spent over a month reading different threads, talking to Les Schwab and Discount Tire and trying to learn anything I could about tires. I finally decided on the Copper Dicovery S/T. I've had them on for 5 days and so far I love them. The don't wander at all, there only a tiny but louder than the XTR's and the BFG A/T's that I have on my 60. The work awesome in the snow (played in 8" of it on Saturday) and so far the work good on wet pavement, and they should wear well.

Before I found this tire I was going to start running a winter set and a summer set of tires, but I think this tire will meet and excide my needs all year round.

Here's the Cooper link

Hope that helps

 

[bc81]

Thanks again for the replies. When using a Severe Snow one of the qualifications is the low temperature fiction of 110 (ASTM-1805) or greater even though the manufacturers will not tell us what it is by individual tire. I’ve read different things regarding performance on ice. Since it would appear that it is not the ice but micro layer of water between the ice and the tire that causes the lack of friction, does anyone have a preference on tire width for this purpose? For instance does a wider tire create enough float to keep from melting the ice or should I be more concerned with how the water is drained? I’ve also read a bias towards not going too wide for summer off road mountain driving.

wider tires for winter? wider = floation, great for sand not so good for snow & ice. i would run a stock width tire or only slightly wider. i have run bfg at's , pro comp at's with good results, i still have winter specific tires for when it gets really ugly ( toyo g02 , blizzak's ). the snow flake symbol refers to softness of the rubber at lower temps as you already know. some at's have this which can be in your favor if you're in an accident during the winter months. the insurance company can't claim you didn't have the proper tires, even though they may not be the best for icy roads etc.
food for thought.

 

[skidaddy]

A little information is a dangerous thing. I had read somewhere that the float to avoid developing friction / micro layer of water / ice was relevant as it was with deep snow. It would seem evacuation of the inevitable water is one those compromises that has to be made, however my usage doesn’t really warrant separate sets of studless tires. At least I have been successful with the stock Michelin with three generations LTX M/S. This not only includes going up the twelve miles to Ski Santa Fe where I Iive form 7,200 ft to 10,000 ft in some bad weather. Also Wolf Creek 10,000 feet (most snow in Colorado), Molas Pass to Silverton, or Lizard Head (really) to Telluride. I think the 80 design just does this well based on the amount of current similar cla$$ vehicles I see in the snow banks or worse. Those folks don’t seem to understand a principle of winter driving, slow down!!!!One criticism I do have of the Landcruiser is the size of the brake pads on the 91 – 97. When they upgraded engine / transmission in 93 the brakes stayed the same as previous years, also same as the 4 runner at the time, geez. I had what I thought was to frequent replacement at 25,000 miles pads and 50,000 miles rotors till I heard worse stories. Took care of that (doubled life) with Akebono pads and a better alloy than OEM rotors, same size though. OEM Michelin LTX 275/70-16 C’s stock weighed 43 lbs. I can get the same size Bridgestone Revo at the same weight. However when I look at the unofficial favorite non-lifted ih8mud size of 285/75/16 Revo it comes in a D at 54 lbs. Closest to OEM Goodyear Silent amour 265/75-16 are 48lbs. The 285/70-16 D is 58lbs. Kevlar weighs.Think I’ll try to stick to stock as close as possible since I’m finally happy with brake performance. Looking at the suggested tires and hope to get buy three get four March/April “snow tire” sales since that tag doesn’t mean anything. Now I guess the last question is 4 or 5 new tires? Have never had a flat on this vehicle. Current tires are seven years from purchase old (salvage one?) and would expect next set to last 8 years 50,000 or ten years / 20% longer with a 5 new tire rotation. Pressing my luck with a different tire and age for the spare?

 

[Grench]

Got bored and verbose.

IMHO YMMV etc...

From my own experiences with tires on one FJ80 and two FZJ80s in on ice & snow:

Worst --> Best on Ice and snow <1" deep
Pirelli Scorpion AT < Goodyear MTR < Goodyear AT < Stock Micheline

Worst --> Best on Snow > 1" deep
Pirelli Scorpion AT < Goodyear AT < Stock Micheline < Goodyear MTR

Worst --> Best on lightly rain soaked oily roads
Goodyear MTR < Goodyear AT < Pirelli Scorpion AT < Stock Micheline

Worst --> Best on clean dry pavement
Goodyear MTR < Goodyear AT < Pirelli Scorpion AT < Stock Micheline

Worst --> Best on mud
Pirelli Scorpion AT < Stock Micheline < Goodyear AT < Goodyear MTR

Worst --> Best on sand
Goodyear MTR < Pirelli Scorpion AT < Stock Micheline < Goodyear AT

Worst --> Best on washboard gravel roads
Goodyear MTR < Goodyear AT < Pirelli Scorpion AT < Stock Micheline

What about rocks? We don't grow them here. The only ones of the above that I've used on rocks are the MTRs (even then not much to speak of) and can't make the comparison.

IMHO YMMV etc...

 

[Crusin]

The AT-S is not a good snow tire, it lacks siping. If you read the background of that tire, you will see that it was designed for baja racing, and works very well as an A/T for everything but snow and ice (also see the mixed reviews on Tire Rack). I love Yokohama tires, but that is not the one for your needs.

For your wants, the Bridgestone Dueler A/T Revo sounds ideal. It is a more road orient A/T that still is more agressive and the stock tires, while providing great wet weather and snow and ice performance.

+1

I Love my Revos, very satisfied.

Done Washington wet weather, over the pass blizzard weather, even summer high speed runs... no complains.

GOODLUCK...

 

[BooKilla]

How do the BFG AT's do on ice and water?

AT's are awesome all around tires. Blizzaks are the only tire that I have ever driven that thrive on snow and ice, but BFG AT's will do just fine. You could drive these tires all year long, in all conditions and feel confident in the performance you're getting.

 

[skidaddy]

Getting back to the Sever Snow symbol when you look up the Revo on the Bridgestone page they show that it includes a set of technologies called “UNI-TAQII”

Bridgestone Tire

Some of these components include

Super EPC
Counteracts the effects of heat giving more flexibility to the tire needed for wet performance.

With Particle Z; better than silica

Hydro Evacuation & Sipping

A concave geometry “Optimal for ice surface”.

Even has a dual layer tread where the formulation of the tire changes at 50% worn, just like the Blizzak. As a matter of fact the Blizzak use the same UNI-T technology. So even Blizzak tires such as the REVO1 do not have Severe Snow rating just like the AT Revo.