Snow Grip

[Horsehammerr]

Finally got to try my Hankook Dynapro ATM 30 x 9.5's in the snow. First, I no longer carry my tools since I retired from construction and that leaves me very lite in the rear. Instead I put together a frame to lock in a group of five 8x8x16 foundation blocks @ 30 lbs. each and five 4x4x16 solid cap blocks @ 35 lbs each. Total 325 lbs tight against the back of the cab to just 8" past the center of the rear axle. Seems to be the perfect setup. Tire pressure 37 lbs rear 42lbs front. With 12" of snow on the pavement and the trails and at a nominal speed I just plowed along uphill and down for 20 miles and never even thought of hitting the 4x4 button.

[F9K9]

Sounds great but, I would have thought that the extra weight centered over the rear axle would have been optimum.

[LoneWolf04]

Seems like a bit high on the tire pressure. Are you getting elevated wear down the center of the tread running that high?

Should take a pic of the setup you put in the bed though.

[green02crew]

My tires wear perfectly at an amazingly high 50 psi. Can depend a lot on the tire.

[Horsehammerr]

My tires wear perfectly at an amazingly high 50 psi. Can depend a lot on the tire.

I don't know what tires or size your running but, I was showing a little extra wear in centers front and rear with only 3 lbs more at both ends. That was 5000 miles ago and the change is showing improvement. Nice and even now. The position of the Blocks works great and I have no shift forward when braking.

[Horsehammerr]

Sounds great but, I would have thought that the extra weight centered over the rear axle would have been optimum.

With the load starting 8" in back of center the blocks fit perfectly to the front wall of the bed. As it ends up I have 87.5 lbs behind center and 237.5 in front of center. That puts 175 lbs over center and the added 150 lbs are split 75 lbs forward 75 lbs rear. I figure a little forward help can't hurt in slippery footing. Plus , with this spread my rear isn't sagging as much as it would with the whole 325 lbs centered over the axle.

[roadrunner]

I run BFG AT KO's and they wear great at 50psi but then they are designed to be run at that pressure.

[green02crew]

Goodyear Wrangler MT/R in 30x9.5

[HenryJ]

Everything you ever wanted to know about tires.

Snow Tread:

Snow tread contrary to popular belief good snow tires are not the wide open lugged mud tires. A good snow tire will have more of an open lug design than a highway tread but it should close enough to compress the snow inside the tread and use the packed snow for traction. Many real snow tires are stud ready, these are steel spikes that can be pressed into the tread to allow for more traction on ice. A good snow tire should have a different rubber compound to provide better ice traction, as a result most real snow tires will wear very poorly when used on dry pavement. Unless all you do is wheel in snow i would stay away from these ans stick with an MT design that has a tighter pattern if snow is your primary terrain.

I would think that a lower pressure would increase the foot print and tend to compress the snow. Snow sticks to snow best. It would seem that would offer the best "snow grip".

Tire Pressure

Tire pressure is another source of tire related arguments. Too little pressure and the tire pops off the bead, too much and it becomes easy cut the sidewall destroying the tire. Right in the middle the tire will stay on the wheel and conform to every pebble in the trail. Too much pressure and you may gain some ground clearance, i run my 36x12.5s on 15x10s at 25 psi on the street and 5-12 on the trail.

Tuning pressure for street use:

Tuning pressure for street use is not too difficult of a task. Learning to adjust your tire pressures for the different terrains you wheel on is a great tool to have. The correct pressure on the street is required as it ensures long tread life, decent ride quality, and predicable handling. Pressure at either extremes on the street will cause issues. Pressure too high and you'll wear the center of the tread off the tires very quickly and this will also produce a jarring ride. Pressure too low and the tires will build up heat, this will kill the tire quickly and cause adverse and unpredictable handling. Many people look at the rated pressure on the side of the tire and assume that is the running pressure, ITS NOT. The pressure listed on the sidewall is usually maximum pressure. Do not exceed the max pressure but that is also not where it needs to be for most short wheelbase Jeeps. The max pressure is directly connected to the maximum load if your tires are rated for 2,000 lbs each. So for an example you have a set of tires that read max pres 35 psi and max load 2000 lbs. If your Jeep weights 8000 lbs loaded you may well need to put 35 psi in the tires, but hopefully that does not apply to you (if it does you need to evaluate what you are bringing with you). Inside the door jam of most Jeeps you will find a label that has a recommended tire pressure, that is great with the stock wheels and tires but once they have been modified those numbers are useless. Here is a comon procedure for finding the correct street pressure for your tires.


Find and empty parking lot.

Inflate your tires to the max pressure listed on the sidewall.

Mark the tires across the tread with a piece of chalk or crayon whatever really.

Drive straight forward several feet, be sure not to turn at all.

Look at the mark across the tread and see which part of mark has worn off.

If the mark has worn off at the center but not at the edges you have too much pressure (duh i already told you max pressure would be too much). Drop the pressure and repeat steps 2-5 until the desired pattern is achieved. Be careful too low of a pressure will rub the mark so always start with too much and work your way down. Loading will play a large roll in your quest for the perfect tire pressure. Normally the front will be slightly more loaded than the rear as a result of the positioning of the engine, likewise a fully loaded Jeep ready for 2 weeks in the woods may balance that out and require more pressure in the rear then normal. Atmospheric pressure and temperature play roles too. Changes between the seasons can effect optimum tire pressure. A 10 degree drop in temp will drop your cold tire pressure by 1 psi. Most tires will lose about 1 psi per month due to porosity of the rubber compound in the tires and slight leaks at the bead. Also altitude makes a difference pressure will increase slightly with a gain of altitude due to the reduced atmospheric pressure. Final determination of proper tire pressure is seat of the pants, go test drive it and play around for a while.

** If this method will not achieve the correct pattern you have selected the incorrect tire width/ wheel width combination.**

Tuning Pressure for Trail:

Tuning pressure for trail use is a little more difficult of a task. Almost every experienced Jeeper knows to reduce tire pressure as soon as thy reach the trail. Airing down will create traction on many surfaces by increasing contact patch (the amount of the tires tread in contact with the ground) also by allowing the tire to conform to irregularities, usually the trail isn't perfectly flat. Also consider that while you air down you decrease the ground pressure (pounds force per square inch across the contact patch) and your ground clearance, so don't over do it. From my experience what i have seen on the trails is a pressure between 5-15 psi depending on the tire/wheel combination and the Jeeps weight. Tuning for the trail is more experience than anything else there are just too many variables at play to give a definitive number, have fun experimenting though!

[F9K9]

Excellent thread and last post.

[roadrunner]

To each his own. 50psi works best for me for mileage and wear.

[HenryJ]

It may be right for your combination. If you follow the procedure highlighted in yellow above, there is no , one pressure that is correct for all vehicles and all terrains.

I would rather be on the high side and have it working perfectly. That always leaves room to go down. That is easier than trying to air up.

One of the rigs on our snow run got stuck. His tires were digging into the softening snow. He dropped the pressure about 10 psi and drove out the rest of the way unassisted where we had to tow a Rover. Playing with the pressure to get it right for you is the best choice. I ran not lower than 20 psi offroad at most. Much of the time, I'd stay around 40 psi until things just got too rough. Either the terrain, or the ride. Dropping to 25 psi really smooths things out offroad in my terrain.
I used to run around 35 psi in the winter most of the time during daily duties. It just felt a little better on ice to me.

I did not add weight, well that is not really true. I had an auxiliary fuel tank that added at least 120 lb behind the axle. A tool box in the back that probably adds another 100 lb, and a winch on the front for another 50 lb probably. Solid as a rock all winter long.

Last report I received was that my old truck was seen in Meridian, Idaho a week ago. Hope it is serving someone well this winter.

[DLP]

I move my bed tool box back over the axle and have 10 45 pound bags of pea-stone in it. If I do get stuck, I umpty a couple bags of stone for traction. Even with the extra weight, in 2WD I think this truck is pretty weak in the snow ( glazed driveway). I have to put it in 4WD to get up and down my driveway. But in 4WD it is like a tank.