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-   -   tire pressure (http://www.wranglerforum.com/f282/tire-pressure-13998.html)

Jma20a 12-13-2007 11:26 AM

tire pressure
 
i live in ct and it has finally snowed. i have a set of dunlop mud rovers that suck in the snow and i was wondering if lowering the tire pressure would help.

parrot head 12-13-2007 02:14 PM

Lowering tire pressure would cause the tire to have a bigger footprint on the road which is not what you want for snow. You want skinny for snow. I'm in Connecticut and have mud rovers too. But my rig is not a DD.:wavey:

soupy1957 12-13-2007 02:33 PM

I'm in Central Connecticut, and was out today (Thursday) on full tire pressure. Had a GREAT run!!
-Soupy1957

Jma20a 12-13-2007 02:40 PM

thanks guys

hmenker 12-16-2007 09:51 PM

Just a Thought
 
This is going to sound like an ignorant question on my part, and I don't want embarrass anyone, but were you in 4H or still in two-wheel drive? I have had Dayton Timberline tires for M&S (cheap rubber) and the original Wrangler Tires (more expensive tires) that came with the Jeep and I have experienced absolutely minimal problem when using 4H no matter what tire I've had. I live in the Appalachian Mountains of Western Maryland where we receive 200-250" of snowfall per year. I've never had to go into 4L expect when I went on a Jeep Jamboree a couple of years ago. But, even with a four-wheel drive, when you're in the snow with the small wheel base of a TJ, you can't run like a "bat out of hell." Again, I don't want to sound ignorant so please forgive me if I am sounding that way. It's only because I really do care and know how many things I have done wrong in the past out of not knowing. Hope this helps.

nicolas-eric 12-16-2007 10:03 PM

the TJ has 4H part time. it´s not for on road use. on snow it can help, but you have to drive carefully because there is no diff between the front and rear axle. that can make that your TJ needs more room for curves.this understeel already come sat lower speed in 4H.
when you live in a region with very much snow i would recommend a set of real snow tires.
and please remember. in 4H you can accellerate better than a 2WD car on snow but you brake as bad as any other car.

4Jeepn 12-17-2007 06:53 PM

Depends... in some cases airing down to get a larger contact patch even in snow may help. Depends on the tire how deep the snow is, is it hard packed, layer of ice and snow etc etc etc.

Triple88a 12-17-2007 07:07 PM

Nico i'm glad you said that. so there is no diff between the front and the rear? I'm curious because when i tried to go on that rock on my sig if i press it easily on 4 hi, only 1 of the tires would spin... :eek:

parrot head 12-17-2007 08:53 PM

Quote:

Originally Posted by 4Jeepn (Post 173030)
Depends... in some cases airing down to get a larger contact patch even in snow may help. Depends on the tire how deep the snow is, is it hard packed, layer of ice and snow etc etc etc.


The wider a tire is the less weight (per square inch of contact patch) is exerted on the road. Wider tires will tend to "float" up. This is desireable in mud, but not in snow. You want the tire to dig down in the snow to get traction. That is why snow tires are usually narrow, it is also why plow trucks have narrow tires. This is also why my TJ with 12.50 width mud tires does much worse in the snow that my Honda Element with its 7" wide tires.:D

debruins 12-17-2007 08:57 PM

Quote:

Originally Posted by Triple88a (Post 173036)
Nico i'm glad you said that. so there is no diff between the front and the rear? I'm curious because when i tried to go on that rock on my sig if i press it easily on 4 hi, only 1 of the tires would spin... :eek:

cause u dont ahve lockers :doh:

yeah but hes right the front DS rotates at the same speedas the rear ds but int eh diff it may split in a different way

Triple88a 12-17-2007 11:17 PM

Quote:

Originally Posted by debruins (Post 173091)
cause u dont ahve lockers :doh:

yeah but hes right the front DS rotates at the same speedas the rear ds but int eh diff it may split in a different way

yes i know, no lockers.. only 1 tire spun in other words the power from all 4 tires was transfered to only 1 tire... Is this possible?

parrot head 12-18-2007 08:04 AM

Quote:

Originally Posted by Triple88a (Post 173152)
yes i know, no lockers.. only 1 tire spun in other words the power from all 4 tires was transfered to only 1 tire... Is this possible?

Is it possible you did not have the transfer case fully engaged into 4hi?:crash:

Jma20a 12-18-2007 11:46 AM

Quote:

Originally Posted by hmenker (Post 172662)
were you in 4H or still in two-wheel drive?

i was in 4h, the problem is when i try to stop, i had a set of kelly safari awr's that had no tread and stopped better. i found that when i air down i can stop in a shorter distance. i didn't feel much of a difference with traction when aired down compared to fully inflated.

Triple88a 12-18-2007 12:46 PM

Quote:

Originally Posted by parrot head (Post 173200)
Is it possible you did not have the transfer case fully engaged into 4hi?:crash:

it was the front left tire spinning.. the rock was on the right side.:eek: if it was one of the rears i see what you mean but it wasnt so..

silvergoat 12-18-2007 01:02 PM

wide tire or skinny I've heard this before. And my opinion is go with wide and let the air out in deep snow, you will have better floatation and go farther. A narrow tire in deep snow will dig down, and if there is no base for the tires to bite your stuck also if you dig down your jeep can only push so much snow before you stop moving. Now if I only drove in the snow onroad I would most likely go with a narrower tire and stay away from deep drifts.

parrot head 12-18-2007 02:37 PM

Quote:

Originally Posted by Triple88a (Post 173275)
it was the front left tire spinning.. the rock was on the right side.:eek: if it was one of the rears i see what you mean but it wasnt so..

If you were in driver's seat, the right rear could have been spining without you seeing it, right?:rolleyes:

Triple88a 12-18-2007 11:35 PM

Quote:

Originally Posted by parrot head (Post 173313)
If you were in driver's seat, the right rear could have been spining without you seeing it, right?:rolleyes:

I would have seen the marks on the ground since it pissed me off, when i was stock i went up there easily and then w/ the 4" lift i couldn't.. the only marks were from the front left tire...

I gotta go on that rock sometime again to update my sig lol, now i'm discoed so i should be able to get up there easily

Jonny15 12-19-2007 01:05 PM

Quote:

Originally Posted by Triple88a (Post 173275)
it was the front left tire spinning.. the rock was on the right side.:eek: if it was one of the rears i see what you mean but it wasnt so..


The reason this is happening is because your differential is actually working properly. See with a locker the diff is locked so the wheels have no choice but to spin together and thats why having lockers is a great advantage offroad.

With a regular unlocked diff the tire that spins the easiest is going to spin. This allows for the vehicle to turn properly because the wheels are spinning at difference speeds. This is why the tire you had on the dirt was spinning and the tire with the most resistance to it (the rock) was not. And the part time 4wd system on you're jeep will not transfer power only to one wheel like an all wheel drive car will. You're back wheels were working just fine, it was just the front ones that were not allowing you to go anywhere because the wheel with the least resistance was spinning.

This is why lockers are so nice, i wish i had the cash for some :(

Triple88a 12-19-2007 04:25 PM

Jonny thats what i'm also thinking but its said above that the front and the rear diffs are locked together at the tcase...

Thats why you cannot have 2 different gear ratios (front and back)

Jonny15 12-19-2007 04:32 PM

actually the front and rear diffs are not locked together, its the front and rear driveshafts that are locked together at the tcase...the diffs still operate as normal

Triple88a 12-19-2007 05:35 PM

right.. still doesnt work though...

Jonny15 12-19-2007 06:35 PM

Right, you still need to have the same gear ratio's front and back because when in 4wd the driveshafts get locked together forcing both the front and back wheels to move at the same speed.

I guess to sum everything up the reason you're jeep only had one wheel turning was because the front diff was only allowing the tire in the dirt to spin because it had the least resistance and the back two wheels were not spinning because the diff was slipping and wasnt allowing the wheels to spin because of the resistance in front (kinda like if you were in 2wd and stepped on the brake and gave it gas....the engine would rev but the wheels wouldnt turn because you're diff would be slipping and not allowing the rear wheels to turn)

Triple88a 12-19-2007 06:45 PM

wait diffs slip?

Jonny15 12-19-2007 06:51 PM

slipping is when the diffs are turning but the tires are not...this is why some rear diffs have limited slip, so they slip but usually dont when that extra traction is needed

Triple88a 12-19-2007 07:39 PM

Quote:

Originally Posted by Jonny15 (Post 173831)
slipping is when the diffs are turning but the tires are not...this is why some rear diffs have limited slip, so they slip but usually dont when that extra traction is needed

You got the wrong info man, difs dont slip.. if they slip you will have huge problems...limited slip is not "one is slipping while the other one is not"..



Open diff is free to rotate so if you turn one axle one way (driveshaft is locked) the opposite axle will turn the other way..Its all gears... what a limited slip does is it adds a set of clutches that keeps both axles "connected" to eachother... it works the same way as a locker does.. it locks both axles together but instead of using direct teeth it uses clutches that can slip a bit... If you set your rig in gear and try to spin one tire, you will never be able to spin it even if the other one is free to move.. In an lsd or a locker, both wheels spin the same direction and if you try to spin it, you will pop a blood vessel before it turns...


http://static.howstuffworks.com/flash/differential.swf

Jma20a 12-19-2007 07:52 PM

not to be an a**hole but how did we go from tire pressure in the snow to an argument on how a diff works, or a transfer case works?

Triple88a 12-19-2007 07:56 PM

lol no arguments here :) just trying to get stuff straight...

Jonny15 12-19-2007 08:30 PM

Quote:

Originally Posted by Triple88a (Post 173843)
You got the wrong info man, difs dont slip.. if they slip you will have huge problems...limited slip is not "one is slipping while the other one is not"..


I didnt mean to say they slip...i guess i used the wrong term...i know how a diff works and i tried to explain but i didnt really know how to word it...my bad

And thanks for the info about lsd...i didnt actually know they used clutches

Also no argument or anything just trying to get some info straight, sorry for getting off topic :doh:

Getting back on topic for pretty much all snow driving on the road you want alot of contact pressure in the snow so keep em aired up. The only time to possibly air down is when going trail riding or something in deep snow so you get a little more floatation and dont dig down as much and get yourself stuck.

Triple88a 12-19-2007 08:46 PM

lol pizza cutters :D


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