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Discussion Starter · #1 ·
I was researching the BFG AT KO's at Tire Rack and noticed they made a point about saying size 275-70-18 is not rated for severe snow. Some of the other popular Tundra sizes are, such as 285-65-18 and 305-65-18. I don't get it. The tread depths are the same. Also, 265-65-18 is, so it's not the narrower width. Anybody know why this is? Maybe they just didn't bother to test this size, so it's not rated.
 

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Honestly i dont know why that is. I got 305's on my truck and they have the mountain snow flake on them so their rated for snow.

Maybe someone with 275-70-18's could tell you if they have the mountain snow flake on them. Im sure they will preform the exact same in snow as the 305's and 285's. If snow is what your worried about i guarantee the AT's will be MUCH better than your stocker ragged trails.
 

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I called and asked bfg about exactly this. I talked to some guy that barely spoke english and he first said that the tread is different on those sizes that aren't rated and they would not be as good in the snow. when I said I wasn't interested in them then he said realistically they would be pretty much the same as all the other sizes...I don't think he even knew what the A/T is.
 

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I don't think tirerack.com is very careful about their information. I was comparing BFG rugged trail and BFG all terrain and this is what they posted.

Rugged trail: Overall diameter: 31.9
Revolutions per mile: 660

All terrain: Overall diameter: 31.1
Revolutions per mile: 648

Does this make sense? Their information is not very reliable (at least in this case).

Why don't you contact BFG directly? I don't see why this particular size is singled out.
 

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I have the 305/55R20's and they have the mountain snowflake as well. I'll be the first to tell you though that these tires aren't that good in the snow. They are obviously better than stock, but any tire as wide as mine (12") is going to be bad in the snow. So generally speaking, a narrower A/T KO is going to be better than a wider one. Hope this helps in your decision making process.
 

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The mountain snowflake has less to do with the tread pattern/size (wider is less effective obviously) then it has to do with the compound used. In order to get the designation the compound used has to remain flexible during sub freezing temps to resist ice and snow buildup and retain it's traction. Most tires have their traction begin to degrade at about 43F and get worse as temps drop (I read all this through some government sites about 2 years ago when looking for winter tires for the GF. This is all to my best recollection).

However, there are some articles that point out the mountain/snowflake symbol has turned out to be more of a marketing ploy by the rubber manufactures association. When testing the severe winter rated tires, there was up to a 30% difference in snow/ice performance between manufactures.
 

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I did some searching around on the BFG site and noticed they have a disclaimer at the bottom of the BFG AT product page ... *Size does not meet the RMA requirements for severe snow conditions. although no tire size was indicated with an asterisk that I could see.

Also found this content on HowstuffWorks

If a tire has MS, M+S, M/S or M&S on it, then it meets the Rubber Manufacturers Association (RMA) guidelines for a mud and snow tire. For a tire to receive the Mud and Snow designation, it must meet these geometric requirements (taken from the bulletin "RMA Snow Tire Definitions for Passenger and Light Truck (LT) Tires"):

1. New tire treads shall have multiple pockets or slots in at least one tread edge that meet the following dimensional requirements based on mold dimensions:
a. Extend toward the tread center at least 1/2 inch from the footprint edge, measured perpendicularly to the tread centerline.
b. A minimum cross-sectional width of 1/16 inch.
c. Edges of pockets or slots at angles between 35 and 90 degrees from the direction of travel.

2. The new tire tread contact surface void area will be a minimum of 25 percent based on mold dimensions.

The rough translation of this specification is that the tire must have a row of fairly big grooves that start at the edge of the tread and extend toward the center of the tire. Also, at least 25 percent of the surface area must be grooves.

The idea is to give the tread pattern enough void space so that it can bite through the snow and get traction. However, as you can see from the specification, there is no testing involved.

To address this shortcoming, the Rubber Manufacturers Association and the tire industry have agreed on a standard that does involve testing. The designation is called Severe Snow Use and has a specific icon, which goes next to the M/S designation.

In order to meet this standard, tires must be tested using an American Society for Testing and Materials (ASTM) testing procedure described in "RMA Definition for Passenger and Light Truck Tires for use in Severe Snow Conditions":

Tires designed for use in severe snow conditions are recognized by manufacturers to attain a traction index equal to or greater than 110 compared to the ASTM E-1136 Standard Reference Test Tire when using the ASTM F-1805 snow traction test with equivalent percentage loads.

These tires, in addition to meeting the geometrical requirements for an M/S designation, are tested on snow using a standardized test procedure.They have to do better than the standard reference tire in order to meet the requirements for Severe Snow Use.
 

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I attached the official definition document from the RMA site
 

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Discussion Starter · #9 ·
Thanks for all the feedback. I think I'm going to go for the BFG's in the 275-70-18 this week. They're about $120 a tire cheaper than 305's and will work without a lift. They should still look ok if I decide to do up to a 3" lift down the road. My Rugged Trails actually did ok in the snow, but I had them siped right after I bought the truck. They're pretty worn now. Love the look of the AT KO's.
 

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Narrower will be better in snow. But not so good in sand. However, you can air them down for driving on sand, as long as you have an air tank or good compressor to blow them up again before you head down the highway.

I have 60,000 miles on mine, summer, winter, towing, off road, highway, logging trail, you name it. Good in everything except sand. Then, I get my winch out!
 

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In Canada there is no snow flake on any of the AT/KO. There was at one time, but because of some questions it was removed. I don't know the details but a family member who manages a tire shop said that there was debate about the tires and if there were winter tires and the result was the removal of the snow flake. I have 305's and there is no snow flake on them.

I asked him why there was still on snow flake on the US tires and he thought there was lass stringent standards than in Canada. The laws might need to be more stringent here because in at least one province, snow tires are mandatory by law so there needs to be a definitive definition of what a "winter tire" is.
 

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All these response makes me want to see if my BFG's have the stinkin snowflake logo on it! Otherwise, I am impressed with everyone's response. Thanks!
 

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I wrote to BFG concerning this last month and their letter simply stated,

. . . Thank you for your interest in the All Terrain T/A KO tires. The All Terrain T/A KO tire provides excellent winter traction. A few sizes did not meet the requirements for the mountain snowflake symbol. The tread compounds are very similar between the tire sizes. . . .

What concerned me was the claim that the tread compounds are very similar. The claim was not that the tread compounds are identical. I like BFG AT tires, but since I live in an area that gets a lot of snow, this does concern me.
 

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When I got mine, I had BFG's, the tread's not aggressive enough for what I would need up here in northern VT to move the snow out of the tread area so the tire can bite the surface underneath. I've replaced mine with steel wheels and hakkappalitas for the winter.

I've now replaced the BFG's with Mich's LT10 and they were ok in the snow the first winter, but now I'm back with my Hakka's.

-Garth
 

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FWIW I had BFG AT/KOs with the snowflake rating and they pretty much sucked in light snow and ice. Much happier with Toyo ATs without the snowflake rating in the same conditions.
 

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This is another letter from BFG, replying to the question whether there is any difference in material in the tires involved.

"The All Terrain T/A KO sizes that do not meet the criteria for the Rubber
Manufacturers Association requirements for severe snow are original equipment tires.
Original equipment manufacturers have their own requirements for tires that are
used on original equipment vehicles."

This sounds like passing the buck to OEM's. Also it sounds to me like a tacit acknowledgment that the tires that do not meet the requirements for severe winter use are made with different rubber. The letter asked me to contact the Rubber Manufacturers Association. Specifically (I asked them specifically), 275/65/18 and 275/70/18 seems to be using a different rubber material (since they are popular tires on trucks) from 285/65/18 which, although used in the rock warrior package, has the snowflake symbol.

This really discourages me from considering BFG AT for my next set of tires since I was thinking of 275/70/18. Instead, I may perhaps go with something like GoodYear DuraTrac, which DOES have the snow flake symbol on tires of THE SAME SIZE (275/70/18).
 

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I almost ordered the BFG for winter, I only need 275/65-18 but the also lack the snowflake rating.

I was looking for a tire that could get me through the winter on trips to upstate NY - the Silent Armour seems to have a short tread life versa the BFG and I heard not much about the Toyo AT yet.
 
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