Letting The Hot Air Out of Your Tires

[konradh]

Since, I am no longer around you guys when offroading to help out on psi ratings for your different offroad vehicles. I thought I would share with you a little experience I have had about deflation. Over the past years, I thought deflation wasn’t necessary – about 3 years ago I had the use of a Patrol Super Safari, took it out on a night drive to Sweihan with some friends, not knowing anything about the necessities of deflation, I had the confidence of going out on the sand, since I thought this vehicle had all the power it needed being equipped with a turbo charger and diff lock. My confidence was soon decapitated, I got stuck and more stuck to the chassis – trying and trying it ended up with me having to call IATC to recover me and pay a hefty 1,000 dirhams to their recovery charges from the area I was stuck which wasn’t too far off the road to just the nearest piece of tarmac. All this trial and failure of getting unstuck had placed so much strain on the engine that eventually on the way home, the engine blew – water had mixed with the oil. Yes, I did some researching over the past few days to write this article as to share both my experiences and also the experiences of experts all over the world with regard to deflation. I hope this will be an informative article, a little bit long, but hopefully not a waste of your time especially for those who are beginners and or still have doubt on which psi ratings to go on.

What affects optimum sand tire pressure?

Optimum sand tire pressure is a combination of many things. However, tires, their construction methods and materials, what your 4x4 weighs, how it is loaded and wheel width all play into the sand-pressure tire formula with great results.

Why Low Pressure Works?

It is a simple fact, why do Eskimos use tennis racket like shoes when walking in the snow? It’s because it makes a bigger foot print and doesn’t let them sink into the snow. With regard to your 4x4 vehicle, it’s the same thing, it’ll keep you driving on top of the sand because your 4 tires have a bigger footprint. Take a look at a camel’s foot, its wide and spread out – all four feet of the camel keep its weight spread out evenly and keeps the camel from tipping over or sinking into the sand.

Optimum Sand Pressure

I always followed a rule of thumb, I would start off with 12psi in front and 10psi in the back. If I got into a stuck in a bad bowl and couldn’t get out by self recovery. I would check again my pressure as heat expands air – if I was still on the start off psi ratings, then I would go down to 10psi in front and 8psi in the back. Why the higher psi in front, its because of your engine’s load and steering is done only in the front, so if you were to do very sharp turns all the time and not wide ones, a low psi would cause you to pop your tire off the rim. Although 12 & 10 should do fine for everyone as a standard rule of thumb.

Another way of knowing if you’re pressure is still too high for the sand terrain you’re going through, is by taking a look at your engine temperature gauge, if the temperature is climbing on your meter, then you’re tire pressures are still too high because your engine is working hard to get you to where you want to go. So there is not much of a flotation going on.

Four Effects of low tire pressure:

Low tire pressure changes four things: footprint; ground clearance; rolling radius and Obstacle rolling resistance. Ground clearance is not that important in the sand although if you’re planning to go over some bushes – please be careful and try to drive around them.

Obstacle rolling resistance is the tire’s availability to conform to obstacles. It plays a big part in the ease of movement.

CAUTION!

The obstacle rolling resistance factor works against you with speed and in the rocks. Soft tires easily bend break wheels. Drive with care when going over a rocky surface, a sabkah, or an area full of bushes. The faster you go, the more chance you have of popping not just one tire off the rim but all four.

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[MegaMoe]

:bravo: