I have a wheeling buddy that runs the 44" Pitbull Rocker Bias on a 5,000Lb. V8, Jeep (trailers it most places) with ProRock 60's and likes them a lot (after substantial grooving/siping).So its the mtr the 44 rocker or ltb. Only gonna see mud and snow. Very little street driving . Maybe 200 miles a month. How are the rockers in the snow... are the ltb any good in the snow...
Have also heard good things regarding the 41.5" Rocker radial too in snow.
You have to factor lifer expectancy for a tire like a bias Irok or any bias for that matter when street use is considered, but especially the soft ones like Iroks.
On the street a bias-ply tire will wear much faster than a radial. However if you are satisfied your road wear will be minimal due to little street travel then go for it. I've had several brands of swampers last decent on the street (never ran Iroks though) when used as a daily driver and weekend wheeler.
Take into account that everything being equal a radial airs down and conforms to the terrain much better then a bias-ply tire ever will, and this offers a significant advantage in snow. Something to consider with the stronger sidewalls offered in today's radial tires (no longer are bias-ply tires needed for their strength advantage particularly when snow is your terrain of choice).
Obviously tire size plays a key role in snow wheeling since the floatation gained from airing down to enlarge the footprint of the tread is so important, making the largest footprint available particularly on a heavier truck so necessary. So with that in mind the 49" Irok would be an excellent choice for it's size and great traction in snow (you may have to consider wider wheels due to it's increased width over a 42" Irok though, something more to consider).
I don't think your flotation would diminish going to either the 42"MTR-K or the 41.5" PBRR compare to a 42" Irok, however the 49" bias Irok would still make the best choice for overall snow performance compared to the smaller sized tires.
Saying that if what your wanting is better tread life w/o the need for an increase in flotation or overall snow performance (compared to the 42" Iroks you've been running) I would lean heavily towards suggesting the 41.5" PBRR (Pitbull Rocker Radial). The RADIAL Pitbull Rocker (and I emphasize Radial because it is the difference that will give you the gain in tread life) should offer great snow performance similar to the 42" Irok while delivering much better tread life on and off highway. I would consider mentioning the new TSL-SX in the 43" size if I thought it would offer better performance then either the 42" MTR-K, 41.5" PBRR or the 42" Irok, but I don't think it would in snow (it probably has the strongest sidewall of any of these tires though) and most likely would have the best mud performance.
Regarding mud performance and these tires, I can't say with any certainty since I have not completed any research or discussed this with the people using them. So my opinion would be only from a theoretical stand point and wouldn't be as accurate. However as as past operator of MTR-K's (only the 35" size) while in mud, I would say the MTR-K's are mediocre at best in mud. The PBRR I would suspect to be better and the TSL-SX's best of the three with the Iroks somewhere in the middle of the pack.
However if all out snow performance is the goal for you Irnmtn then the 49" Irok with the widest bead-lock wheel you can find would be the answer your looking for and damn the tread life.
Another aspect to consider is the weight of the tire or the tire and wheel combined. Excess tire and wheel weight takes it's toll on axles/u-joints and works all aspects of the drivetrain harder and is just one more item in a 4x4 specifications that should be considered if a better performing vehicle is your goal. While there are few choices in the larger sized tires (40"+) it still should be a piece of the puzzle to consider. Thankfully most tire and wheel manufactures offer the weights of their products making comparisons easy. Radial tires generally are lighter, but not necessarily as some bias-plys like the Interco Irok weigh less then a similar sized radial tire.
For a little comparison all the serious snow wheelers that are in the Kelowna, BC, Canada, an area which is a very popular spot to go snow wheeling and is known for producing some of the most capable snow wheeling 4x4's on the planet, bias-ply tires are it. The local hard core group are all on bias ply tires starting at the 44" size and going up to the 54"+ size, although most trailer their rides or do not daily drive them much.
These wheelers are all about maximum performance in the snow and cost isn't really a concern when contemplating tires. If radials were better they would be running them, even if the cost was higher; these wheelers recognize the gains from the larger sizes offered only in bias-ply tires. Unfortunately at this time the common wheeling brands of radial tires only come in sizes as large as 42"s, but if that changes then you may see 49" bias tires traded in for 49" radial tires provided they measure as wide. I say as wide because the width of a tire is the more important aspect to consider when maximum flotation is the goal.
Okay here's where I go a little to far, so for all those reading please excuse my rambling...:shaking:
When trying to figure out the flotation performance of a tire I take the tires height and multiply it by 3.14 to get it's circumference and then I multiply it again by .22. This .22 number is my personal estimate of the percentage of the tires circumference or tread that will contact the ground when aired down. Then that number needs to be multiplied by the width of the tire when aired down which is usually the tires width plus an inch or two. Finally I multiply that number by four to allow for the footprints of all four tires to be combined. Then I can compare the vehicles known wheeling weight to the total square inches that all four tires add up to when aired down. I then can calculate how much flotation I can expect compared to another set of tire that are a different size.
As an example, a tire with an actual tire size when on a wheel measures: 40"x 14.50" so that...
126"(=Tire circumference)x.22(which is an estimate I have calculated from aired down tires as a percentage of the tires circumference)=*28"
28"(=length of tire in contact with the ground)x16.50" (14.50 plus 2 inches which is what I expect the tire to air out like at single digit air pressures)=*456"
456"(=total square inches of the tread in contact with the ground)x4 (represents all four tires)=1848"
(Please note that this symbol * represents the fact that I rounded up all those calculations before completing each next calculation.)
So a 4x4 with a set of four 40"x14.50" tires aired down will be displacing approximately 456"Psi. (Pounds per Square Inch) Pounds per Square Inch and when you consider that all four tires offer 1848psi and the vehicles weight is 3,700lbs. the 4x4 is distributing approximately 2psi. of pressure through the tires.
Now when we switch that same vehicles tires to 49"x19.5" tires we can compare the difference swapping to an even larger tire will offer with respect to the tires flotation capabilities when aired down.
Okay, so a tire that is 49"x19.5" again aired down to single digits is... Again we add two inches to the width to allow for the tires increased width from airing down into the single digits of air pressure like 5Psi. for example.
152"(=tires circumference)x.22(=approximation of the percentage of the tire that is in contact with the ground when aired down)=*34"
34"x21.5"(=tires width in contact with the ground when aired down)=731"
731"x4(=amount tires on vehicle)=2924"
(again the * symbol means I rounded up before completing the next calculation)
Now you can do an approximate estimate of the gains made in floatation by switching to a larger tire. In this comparison the 40" tire offers an approximate 2psi. while the switch to 49" tires offers a 1.25psi. contact patch which is considerably less then the 40" tires contact pressure.
When you compare a heavier vehicle say a one ton full-size 4x4 truck for example you can really begin to see why keeping your weight down helped so much with flotation.
In this example a truck weighing 6,000lbs. with a set of 49" tires has the same flotation value as a 4x4 weighing 3,700lbs. with a 40" set of tires, we can confirm this by doing the math.
The 6,000lb. truck running 49" tires with a combined footprint of 2924psi. means the truck will be putting down a combined pressure of approximately 2psi. (6,000 divided by 2924=2.05)
Versus a 3,700lb. 4x4 with 40" tires equaling a combined pressure of 2psi. (3,700 divided by 1848=2.00)
So the 3,700Lb. 4x4 would have similar flotation abilities to the full size truck running 49" tires in the snow when discussing the vehicles displacement over the snow.
There are other variables to consider when building a 4x4 for snow wheeling, but this is big one to consider when contemplating tire size and vehicle weight and how when combined they equal the vehicles ability to stay on top of the white stuff.
Okay who can tell I can't sleep tonight, well for those that made it all the way congrats