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Sonata
04-05-2013, 09:13 PM
Looking for someone with a bit more mechanical savvy than me to clarify something for me...

So my MC went and got her Jeep stuck in a snow bank. The rear driver's side tire is up in the air. My question is if that is the tire that actually spins to propel the vehicle?

Also, when she puts it in four-wheel and tries to back out, the opposite tire (passenger front) would be the other one pushing right? So if she can't get traction with that one she should be sufficiently stuck, right?

I don't want her to be able to just pull out and drive away, but I also don't want to total her vehicle in the accident. I just need to make sure this is accurate before I move on.

Thanks in advance!

jclarkdawe
04-05-2013, 09:36 PM
My guess is if one tire is in the air, then the Jeep is resting on the frame/underbody and not the tires. In other words, there's no pressure on the tires and all of them will spin. Only way you're going to come off is to shovel out under the car or a winch/tow truck.

Best of luck,

Jim Clark-Dawe

King Neptune
04-05-2013, 10:10 PM
I agree with JCD.

Have the thing get stuck in a snow bank up top the windows. It is reasonable that one wheel might spin that way. Putting it four wheel drive wil put power to all four wheels, and the thing should come out, unless the driver is a moron and revs the engine so the tires spin and ice forms under them. That's how to leave a car in a sonbank.

Cyia
04-05-2013, 11:00 PM
Define "up in the air". If it's a couple of inches off the ground, you can put a board or something similar under the other tires (sometimes even cardboard will work) and use something a bit thicker to make up the difference with the elevated one. If it's a foot or more off the ground, I hope you have a cell signal and a friend who doesn't mind getting out in the snow to pull you out.

Drachen Jager
04-06-2013, 12:27 AM
As important as four wheel drive in these situations (perhaps more important) is the differential lock. Normally it is turned off, and the mechanism for turning it on varies from one vehicle to another. When it is on, each axle works like a solid rod, when it's off, each wheel spins independently and all of the torque will go to the wheel that's spinning freely.

ironmikezero
04-06-2013, 01:15 AM
Knowing the year & model would help...

If you're not familiar with the tech, these sites might help...

http://www.motortrend.com/features/consumer/1105_4wd_vs_awd/viewall.html

http://en.wikipedia.org/wiki/Jeep_four-wheel-drive_systems

http://www.awdwiki.com/en/jeep/

quacktaculaura
04-06-2013, 05:02 AM
I would say that your best bet is to have her get high centered on the snow. None of the tires necessarily need to be off the ground in order for them to lose traction. I agree with ironmikezero though, in that knowing the year and model makes a difference. We currently have a Jeep Rubicon. It has differential locks in addition to the four wheel drive. The differential lock basically locks the two rear or two front tires together so that they have to spin at the same time.

A vehicle with a limited slip will automatically put power to the tire that has traction. So if there is one tire in the air, that tire will only get a small percentage of the power, and the tires on the ground will get the rest. However, if it's running an open differential, the tire that doesn't have any traction will get all of the power leaving it spinning and your MC stuck.

My husband and I took my old Jeep Cherokee up a trail one day. We were trying to get through an avalanche basin and ended up with all four tires sunk down into the snow. We couldn't get traction. All tires were on the ground, but they were all spinning. We finally ended up with him rocking the Jeep back and forth while I tried to reverse it in order to get it out.

Sonata
04-06-2013, 06:12 PM
Thanks everyone!

Its an old Jeep Cherokee, probably mid 90's. It wouldn't have all the fancy sensors and positrack or whatever. Sorry, my interest in vehicles is nil. I just need enough info for it to be feasible.

Really, the scene is just another way of torturing my MC. I don't want to have to spend much time on it at all, I'm so deep in other research my head is spinning.

I just need my MC to get stuck in a snowbank and have to call for help. She's by herself in the middle of nowhere, so she won't have much to work with. Maybe I'll go light on the details, make sure she gets the frame up on the snow enough that she can't get any traction and that should work, eh?

WeaselFire
04-09-2013, 12:57 AM
High centering on the bank is the way to go. At best, she'd need someone to push, at worst, a tow. I've done this with several 4WD vehicles in snow, mud, sand and swamp, including a '94 Cherokee, '86 Wagoneer, '72 Jeepster Commando and a 2007 Wrangler. Though I was prepared for most (spun a 4WD Subaru into the snow avoiding a squirrel and had to be pushed out), without a winch she would need help.

Jeff