Tire pressures in snow?
01-13-2009, 08:06 PM
#11
JK Freak
When we go snow wheelin we go down not up. With snow deeper than the space between the bottom of your tires and the axles or body your tires will try to reach solid ground you will NOT go anywhere. Airing down so your tires get wider and you stay on top of the snow is much better.
My regards,
Widewing
01-14-2009, 07:54 AM
#12
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i have 37s i take them down to 8 psi no matter what the situation
lower psi always = better traction in any situation. the goal is for the tire to kind of mold around the ground. i dont think pizza cutters work better in snow. wider tread is more traction digging through the snow. pizza cutters dont part the snow like moses and the red sea. your still driving on snow regardless so why not have more rubber.
lower psi always = better traction in any situation. the goal is for the tire to kind of mold around the ground. i dont think pizza cutters work better in snow. wider tread is more traction digging through the snow. pizza cutters dont part the snow like moses and the red sea. your still driving on snow regardless so why not have more rubber.
01-14-2009, 08:14 AM
#13
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I don't know guys, I'm at a loss to understand why some swear that airing down to damn near flat is beneficial.
Maybe it's because most of you are running Mud Terrain type rubber. Most of these are less than adequate in snow. Hard compounds and ultra-stiff sidewalls reduce the chance of being cut on sharp rock, but these tires simply don't flex when cold.
That's why AT type tires are usually superior in snow. Far more gripping edges and greater flexibility are key. Modern "winter" tires will not work at all if significantly under inflated. Try running a set of Blizzaks at 10 psi and see what happens.....
I would never run Mud Terrains in snow if I had another option. That is the primary reason that I left the stock SR-As on my JK for the winter. They are vastly better in snow than the BFG MT KMs that come on the Rubi. I've driven both types in snow, and an X with 32" SR-As will simply drive away from a Rubi in fresh snow. We discovered that a few weeks ago. We (me and the wife) were following my Friend Paul in his unlimited Rubicon along some fire roads out in the Pine Barrens. About 6 to 7 inches of snow. Some snowmobile tracks, but no wheeled vehicles other than perhaps an ATV had been down them. Paul was creeping along at 5 mph. We stopped and I asked why he was so slow... Poor traction. We switched positions and he couldn't or wouldn't try to keep up. Poor tires, as simple as that. We swapped Jeeps for the ride back. He was right, the BFGs wouldn't hook up. The Jeep would step out, moving sideways as much as forward. It would understeer like mad and the ABS would kick in with the slightest pressure on the brake pedal. I double-checked to make sure he hadn't disabled traction control. I shifted into low range and
tried the lockers. Some improvement, perhaps. But, no great shakes. The Unlimited was a 6-speed (silver, soft top), my X has the automatic with LSD rear axle. It was the tires... The BFGs are barely marginal in snow.
That said, I've been driving in snow for 40 years. I've owned three Jeeps, a 4x4 Ranger, a Samurai, a 4dr Sidekick and my wife's '03 Grand Vitara. In all those years; in all those 4x4s; in snow as high as top of my YJ's bumper, I've never gotten stuck. Stuck meaning unable to extract the vehicle without assistance. Not once. I don't air down tires either.
Get a set of tires that work well in snow...
My regards,
Widewing
Maybe it's because most of you are running Mud Terrain type rubber. Most of these are less than adequate in snow. Hard compounds and ultra-stiff sidewalls reduce the chance of being cut on sharp rock, but these tires simply don't flex when cold.
That's why AT type tires are usually superior in snow. Far more gripping edges and greater flexibility are key. Modern "winter" tires will not work at all if significantly under inflated. Try running a set of Blizzaks at 10 psi and see what happens.....
I would never run Mud Terrains in snow if I had another option. That is the primary reason that I left the stock SR-As on my JK for the winter. They are vastly better in snow than the BFG MT KMs that come on the Rubi. I've driven both types in snow, and an X with 32" SR-As will simply drive away from a Rubi in fresh snow. We discovered that a few weeks ago. We (me and the wife) were following my Friend Paul in his unlimited Rubicon along some fire roads out in the Pine Barrens. About 6 to 7 inches of snow. Some snowmobile tracks, but no wheeled vehicles other than perhaps an ATV had been down them. Paul was creeping along at 5 mph. We stopped and I asked why he was so slow... Poor traction. We switched positions and he couldn't or wouldn't try to keep up. Poor tires, as simple as that. We swapped Jeeps for the ride back. He was right, the BFGs wouldn't hook up. The Jeep would step out, moving sideways as much as forward. It would understeer like mad and the ABS would kick in with the slightest pressure on the brake pedal. I double-checked to make sure he hadn't disabled traction control. I shifted into low range and
tried the lockers. Some improvement, perhaps. But, no great shakes. The Unlimited was a 6-speed (silver, soft top), my X has the automatic with LSD rear axle. It was the tires... The BFGs are barely marginal in snow.
That said, I've been driving in snow for 40 years. I've owned three Jeeps, a 4x4 Ranger, a Samurai, a 4dr Sidekick and my wife's '03 Grand Vitara. In all those years; in all those 4x4s; in snow as high as top of my YJ's bumper, I've never gotten stuck. Stuck meaning unable to extract the vehicle without assistance. Not once. I don't air down tires either.
Get a set of tires that work well in snow...
My regards,
Widewing
Snow as high as the top of your YJ's bumper is one thing. REAL snow...DEEP snow...that's something else.
Besides which...physics and common sense tells me that lower tire pressure=wider footprint=lower ground pressure=better flotation.
If you don't believe that better floation is beneficial in deep snow, then how about we try something. I'll put on snow shoes, and you stick with running shoes. Then we'll see who has more fun walking a mile through snow that's three feet deep. Any guesses as to the outcome of that?
Driving in snow that's less than two feet deep and dealing with ice/slush/packed snow on roads is one thing. Going off-road in real snow country (especially mountains) is another.
As far as the BFG KM's being poor in the winter...there's an easy solution to that. Sipe them. $30/tire, and they'll perform just as well as a good AT. That's what I'm running on my Jeep now, and they're working just great. Even better than an AT when the snow gets really deep.
I should know...I've put hundreds of thousands of miles on one ton trucks that were equipped with BFG and Toyo AT's on some of the worst excuses for roads in North America. Driving a Jeep as your hobby will teach you a few things. Driving into places that most people would refuse to go in order to make a living...that's a whole new degree of learning.
01-14-2009, 09:17 AM
#14
JK Freak
Besides which...physics and common sense tells me that lower tire pressure=wider footprint=lower ground pressure=better flotation.
If you don't believe that better floation is beneficial in deep snow, then how about we try something. I'll put on snow shoes, and you stick with running shoes. Then we'll see who has more fun walking a mile through snow that's three feet deep. Any guesses as to the outcome of that?
Driving in snow that's less than two feet deep and dealing with ice/slush/packed snow on roads is one thing. Going off-road in real snow country (especially mountains) is another.
If you don't believe that better floation is beneficial in deep snow, then how about we try something. I'll put on snow shoes, and you stick with running shoes. Then we'll see who has more fun walking a mile through snow that's three feet deep. Any guesses as to the outcome of that?
Driving in snow that's less than two feet deep and dealing with ice/slush/packed snow on roads is one thing. Going off-road in real snow country (especially mountains) is another.
Nonetheless, your snowshoe argument is badly flawed. A snowshoe offers about 10 times the area of a running shoe. Airing down your tires increases tread area by less than 10%. So, an equivalent test would be me wearing size 9 and you wearing size 10. Will there be a measurable difference? No, none.
You also managed to lose the context of the original discussion. A fellow going trail riding in about 12 to 16 inches of snow wanted to know what tire pressure was best.
Furthermore, when I lived in Maine, I had to drive in snow every day from November to April just get to work. Frequently, it was deep and not yet plowed. Jeeps and 4x4s have been my daily drivers for more than 25 years.
My regards,
Widewing
...............
01-14-2009, 12:29 PM
#16
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To the OP... It appears that you have two very different answers to the question of what PSI to run off road in the snow. One is to run higher PSI and the other to run a lower PSI. I say try both! Start out the trip running with the +2psi that Widewing has suggested and if that doesn't workout for you... drop down to the 8-15psi range that others have suggested. And please do post what worked out the best for you.
I personally I don't drop PSI unless I need to... Started at 37psi spinning not going anywhere (not pictured) and dropped just to 22.5psi (would have gone lower but not able to air up for the drive home) and achieved this...
I personally I don't drop PSI unless I need to... Started at 37psi spinning not going anywhere (not pictured) and dropped just to 22.5psi (would have gone lower but not able to air up for the drive home) and achieved this...
01-14-2009, 01:59 PM
#17
JK Junkie
For me and the tires i run, both the Xterrains and the stock bfg's, there siped and doing on-road i kept at normal road pressure. Going off-road in snow deeper than your bumpers low pressure.
01-14-2009, 03:21 PM
#18
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I ran 18PSI on the street the other day when it snowed, and highway, and it gripped quite well. On 28PSI, I had some tire spin, on 18PSI, hardly any.
When snow wheeling, 8PSI.
When snow wheeling, 8PSI.
01-14-2009, 03:40 PM
#19
Widewing,
Check out Goodyear Silent Armor tires. Best snow/ice tires I ever ran. I liked them so much I now have a set on my "X" Unlimited and I only see snow once or twice a year. They are also pretty good in sand when aired down.
Check out Goodyear Silent Armor tires. Best snow/ice tires I ever ran. I liked them so much I now have a set on my "X" Unlimited and I only see snow once or twice a year. They are also pretty good in sand when aired down.
01-14-2009, 03:44 PM
#20
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Physics is what I do for a living... I won't debate over anyone's head to make a point and lose the interest of the readers.
Nonetheless, your snowshoe argument is badly flawed. A snowshoe offers about 10 times the area of a running shoe. Airing down your tires increases tread area by less than 10%. So, an equivalent test would be me wearing size 9 and you wearing size 10. Will there be a measurable difference? No, none.
You also managed to lose the context of the original discussion. A fellow going trail riding in about 12 to 16 inches of snow wanted to know what tire pressure was best.
Furthermore, when I lived in Maine, I had to drive in snow every day from November to April just get to work. Frequently, it was deep and not yet plowed. Jeeps and 4x4s have been my daily drivers for more than 25 years.
My regards,
Widewing
Nonetheless, your snowshoe argument is badly flawed. A snowshoe offers about 10 times the area of a running shoe. Airing down your tires increases tread area by less than 10%. So, an equivalent test would be me wearing size 9 and you wearing size 10. Will there be a measurable difference? No, none.
You also managed to lose the context of the original discussion. A fellow going trail riding in about 12 to 16 inches of snow wanted to know what tire pressure was best.
Furthermore, when I lived in Maine, I had to drive in snow every day from November to April just get to work. Frequently, it was deep and not yet plowed. Jeeps and 4x4s have been my daily drivers for more than 25 years.
My regards,
Widewing
So your trying to tell me that by airing down your tires there really is no measureable difference.
So then why does everyone air down there tires when rock crawling and off roading?
The answer to that question..........
1). Wider foot print
2). Tire will mould around rocks/terrain for better traction.
Just my .02
But what would I know...I own an XK not a JK