2nd Gen Non-Engine/Transmission different tire size much better in snow

[mainer]

I went from the factory size 245/75 to the taller and narrower 235/85 and the handling and traction in snow is markedly better. Even in 4WD, with the factory size my truck was like a beached whale, particularly if the snow was over 6" deep. I had tried Kelly Safaris, and Michelin LTX M&S.

 

[FJfonda]

For the full beached whale experience... ... . take a 3500 for a ride in the snow! It goes pretty well but wags it's tail the whole way.

 

[SRadke]

The Michelin LTX is one of the best snow/ice traction tires out there IMHO. Often it is not a function of size as much as the rubber compound and tread design of your tires.



-Scott

 

[Intelman34]

I have the 265/75/16 Michelin LTX/AT's on my truck and they are pretty crappy even when there is just a dusting of snow (thats all we ever get in Southeastern WI). Rain is even pretty bad with them. Oh well, at least the truck has 4WD.



What pressure are you guys runnin?



For RWD vs RWD, my Z28 was easier in snow.

 

[Ncostello]

Those sizes are really too close for the size alone to be of any difference. Perhaps the taller 235 may decrease the gearing ratio slightly thus giving some slower take off wheel speed for the same mph as the 245's. Kinda helps keep wheel spinning from happening as easy from all the torque.



Its all in the tire tread. I had a Z-71 4x4 and some really good snow tires. They were 245's and I could literally climb over snow drifts. I've seen 245's that were no wider than certain 235's depending on the brand... just shorter.



Sipes in the tread and specific tread patterns that help produce the "snow on snow" traction idea is whats helpful.



I just replaced General Grabber 235/85's with Kumho KL-41 AT's in a 245/75 factory size. The tread depth and design alone make tons of difference for me. But in general... narrower tires tend to produce more ground pressure which is what helps on slick snow.

 

[diesel DOG]

I just bought a 235/85 yesterday and used my spare to get two new fronts for the snow. I was thinking wider buy it went get last year in snow and mud. I didn't want to buy French but didn't want to buy a entire set for a few more months. I realy forgot how deep the new tire tread is. :--)

 

[Gregg Mig]

I put Cooper Discoverer M+S on an extra set of chrome wheels and they work great. I went with the 235x85 16's the narrower tire puts more psi on the snow for better grip. These tires are the same height as my stock 265's. I do quite a bit of plowing and on the last storm these tires just don't slip even on hard pack. If you want more grip they can be studded. I bought them in October for $103 apiece mounted and balanced.

 

[Joe Pool]

In my experience, one of the best snow tires that I have used is the 255/85R16 BFG Mud Terrain KM. They are a little taller than stock and a tad wider than a 245. They really bite through the snow. I used them on my '98 V10 Ram 2500 and loved them. I am currently running 285/75R16 Dunlop Mud Rovers due to the weight that I carry [ 255/85R16 = 3000# & 285/75R16 = 3400# load rating]. Also a 255 will fit in the stock spare tire location and are a perfect fit on the factory rim.



Joe

 

[Loren]

Neil,



A narrower tire will not produce more or less ground pressure than a wider one. The ground pressure is basically equal to the tire pressure. This is why four-wheelers "air down", or drop tire pressure when on sand and similar surfaces.



Loren

 

[JohnE]

I haven't tried the LTX, but every other Michelin tire I've owned has been the most pathetic tire in snow imaginable.

A friend had LTX on his truck. They were worthless on ice and not much better on snow.



In addition to putting the same vehicle weight on a smaller tread width, you also have LESS snow or mud to push aside with the smaller profile.

Local tire shop guy says the best all around winter & mid tire is going to be an 85 series. He also drives a diesel (Ford PS) pickup and has a sizeable range of other pickups in both gas & diesel.



Farm tractors run multiple tires and tracks for less soil compaction. Logging equipment that require maximum traction run single tires & chains.

 

[Ncostello]

Just as Dl5treez said. Thats why Caterpillar LGP (low ground pressure) dozers exert half the weight per square inch than a regular dozer track.



Its PSI... or pounds per square inch... or pounds/square inch. Thus if the square inch portion of the fraction is increased the number gets smaller. Airing down increases the square inch area.



Ground pressure has nothing to do with inflation pressures. Ground pressure is the total weight of the truck divided by the contact patch area of the tire. A solid rubber tire exerts the exact same ground pressure as a pneumatic tire if the weights and contact patch areas are the same.



If you had saw blades for tires... you would exert enourmous ground pressure and go right to the bottom of snow to solid pavement... and possibly through the pavement too .



Ladies in high heel shoes are not allowed on gym floors but elephants are.

 

[Loren]

I know that many drivers do not believe it, but the fact is that, within engineering tolerances, the pressure on the ground is equal to the tire pressure.



The ONLY thing that causes them not to be exactly equal are any compression or tension forces that are carried by the tire sidewalls.



When you let air out of a tire, the contact patch enlarges to maintain the same force. Pressure times Area equals Force. In this case, the force is the weight carried by that tire.



I have had this discussion on at least one other forum and do not intend to debate it. You don't have to believe it, but that does not make it less true.



Loren

 

[JHoegner]

I had a set of Michelin 245/75/16 LTX/AT for my truck and they were great, they wear and ride well, they were my summer tires. Never had a problem with them, ran them at 40PSI and did a lot of highway driving. For winter I had a set from Canadian Tire, Roughrider M+S made by Coopertire, (AKA: Cooper Discoverer M+S in the USA, I believe) very nice in the winter, even had the holes for studs. It is important to consider a few factors when picking out tires: what will the truck be hauling, what surface type will the truck be on mostly, how much mileage do you want from the tires, will you use them year round, does the design of the tire suit your needs?



Now getting into ground pressure, I was at the Mattracks website and they had this to say: "A standard truck with tires will exert up to 40 p. s. i. of down pressure on it’s tire contact area. A person standing will exert 6 to 8 p. s. i. of down pressure. "



http://www.mattracks.com/html/faq.htm



I found even more on ground pressure:

http://www.4x4now.com/sfjun96.htm

http://www.michelinag.com/agx/en-US/about_us/history.jsp

http://www.plpa.agri.umn.edu/extension/news releases/mncn57.htm

http://www.orsis.de/Papers/1999_Muenchen_Lach.pdf

http://www.orsis.de/Papers/1997_Ferrara_Lach.pdf



I hope that these sites provide the answers that some of you are looking for. I learned quite a few new things.

 

[Ncostello]

I dont want to debate either. Its not that big of a deal.



I could see that the ground pressure in the tire is equal to the inflation pressure times the contact patch area. I haven't... and am not going to do engineering calculations. But it would make sense since when you air up a tire... the tire will lift the vehicle up. Thus the air pressure inside the tire is supporting the weight of the vehicle. Otherwise the vehicle would still be sitting on "flat" tires.



On the floating issue... the only thing that really determines whether or not an object will float in water depends on its weight versus the displacement weight.



When you place an object in water, it displaces a certain amount of water. If the object weighs less than the amount of water it displaces it will float. Of course the shape of the object plays a big role in the amount of water displaced. Obviously an air craft carrier weighs less than the amount of water it displaces when put in the water. But if you took the same amount of steel and wadded it up in a ball... it would sink because of the more dense size versus the same weight.



I'm getting off topic. And it does make sense that the inflation pressures times the tire patch area = vehicle weight = ground pressure. Except in the case of solid tire vehicles such as trains.

 

[mainer]

I'm not too clever, but I'm guessing that the taller, narrower tires I put on provide better traction with similar tread mostly because they have a longer foot print relative to width therefore digging in better. I could feel those factory size tires pushing snow, instead of digging in.

 

[WadePatton]

Well, I got here late, but I'll have to throw in a comment or two that might help.



Given same inflation pressures--Narrow tire has longer contact patch than wide tire. Total contact area is very close to the same.



Contact patch shape affects maximum traction. The long patch being better for acceleration/braking and the wide patch being better for lateral forces--cornering. At least according to my racing chassis learnin.



And yes--the longer patch has less frontal area to compress the snow, so will run deeper in the fluff.