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Why air down your tires? and how Low? small article i found for all you 4wheelers
Posted 06 September 2003 - 11:15 AM
Airing down does two basic things to help us maintain traction. First, it allows for a longer and wider footprint. This is important because the more rubber you keep in contact with the terrain, the more traction you will have. In many cases, you can increase your contact with the ground over 200% by airing down. This will increase your overall traction as much 800% assuming you have 4 tires on the ground.
The second thing airing down does for us is that it allows the tire to conform to uneven surfaces. If you imagine your foot for a moment in heavy boots standing on a log, you can see that only a very small portion of your foot is actually in contact with the log at any time. Remove the boot and stand on the log with your bare foot, and your foot can bend and conform to the log giving you a much more firm grip. Tires need to do this when trying to get grip over rocks, gravel, sticks, etc. The difference is truly amazing. An added side benefit is that reducing the pressure in your tires softens the ride tremendously while off-road.
How much air should I use?
This is an issue of MUCH debate. Land Rover recommends that the stock tires should not be aired down below 16 psi in the front and 25 psi in the rear. In truth, with a standard load in the rear, this is probably good advice. If you take out too much air, you run the risk of rolling the tire right off the bead. This is very likely with the stock tires since they really don't grip the rim all that well to begin with. With off-road tires in the larger sizes, you can go lower. I have had my 215/85r16 tires at 12 psi without trouble but I don't recommend going that low. I will defer to a chart provided by Oasis-Offroad. They have taken the time to determine optimum tire pressures for off-roading for a range of different sized tires on vehicles of different weight. While the chart is by no means comprehensive, it does offer good insight into what you should be looking at. Please note that Oasis maintains no responsibilty for the accuracy of this chart and bears no responsibility if you have a loss.
So you can see that this is really not a complicated affair, but one that every off-roader should pursue if you want maximum traction off the road. One thing of note. If you plan on airing down off the road, be SURE you have a way to get air back into your tires when you are done."
article by j of Arizona Backcountry
Thought this would be some interesting info for all you four wheelers out there without having to join this club.
Posted 06 September 2003 - 12:06 PM
Posted 06 September 2003 - 12:08 PM
When we got to the Rubicon I started to air down for that exact reason but it was suggested(by my co-pilot) that I wait until I absolutely needed the extra traction. Well, long story short, I ran the trail at street pressure and maintained my overall clearance and had no traction issues. The only time I have had problems with my tires in the past is when I aired down.
I should add that most of the people who air down have much larger and stronger engines then our Subes have. They air down to help eliminate tire spin as much as traction.
Posted 06 September 2003 - 12:14 PM
One of my jeepin buddies has beedlocks, and he can air down to 8psi easily. That with all his crawling gadgetry... he can go almost anywhere.
Posted 06 September 2003 - 04:53 PM
Subaru's really shouldn't air down for rocks and whot not, cause too much traction can cause you to destroy axles, (or stubs in the diff's) Some slip is better on the drivetrain. I've learned that one the hard way.
Posted 06 September 2003 - 05:20 PM
Posted 06 September 2003 - 05:27 PM
My father's answer to everything off-road related is airing down your tires. everytime I explain a story about me and off-road, he always asks "did you air down your tires?"
One time I was off-road with my Wagon, before the lift, before the tires. I was running 175/70R13's, bald street tires and i was stuck in the mud. Picture:
Anyhow. when my father came to pull me out, the 1st thing he asked was "did you air down your tires?" After I said no, i explained why.
So, he came with his '94 Jeep Cherokee, with a 4" lift and some larger tires with mud tread. came to the hole, aired down his tires. After he got stuck in the mud, with the aired down tires and all... he started to rock the jeep back and forth. Until the front axle snapped.
Posted 06 September 2003 - 06:30 PM
Posted 07 September 2003 - 03:56 AM
and i am like get a subaru, they are pimp. and they are like,wei like 2wd. i'll stichk to my crapalier.
and i am like what about the baja'n
and they are like i'll get a jep
and iam lilke, but jeep didnt make a turbo!
and then i get fired for putting stickers on the drive thru
Posted 07 September 2003 - 03:55 PM
i usually run around 12 psi cold with my old tires, now i need to find a happy medium for my new tires. if i don't air down it's a lot bumpier and more impact when a tire comes back down, along with i do notice the traction difference.
not airing down makes my car bounce all over, and i break more stuff, so there's no way are you talking me out of it. i see too many benifits, and to little draw backs not to.
1. less bumpy
2. less impact on parts when tires comes down
3. better traction
1. largest drawback you might lose a bead (been there done that)
2. lose a small piece of diff clearance, (not enough to worry about, 8psi up isabele lake tr.)
i've been 4x4ing since i was 11 and i've seen situations that go both way's for airing down. but i've seen a lot more benifits come from airing down. judge your terrain and what your comfortable with. just trying to give you guys an article for those who air down to take estimates to find there happy medium for airing down.
Posted 07 September 2003 - 05:07 PM
Works well in mud and snow also.
If you air down too far, under 10lbs, the contact patch can bow up in the middle and lose contact.
Good advice about not airing down till you need to.
Posted 07 September 2003 - 05:24 PM
Posted 07 September 2003 - 06:12 PM
Posted 07 September 2003 - 11:20 PM
Posted 08 September 2003 - 12:35 AM
Posted 08 September 2003 - 08:30 AM
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