To Air down or not?

Right you want more traction and understand bigger tyres alone will not give it are there other options?

Air Down Or Not To Air Down?

Here is a little story, one competition we went to our tow vehicle broke down (that is another story oil got in the radiator) anyway the offroader being reg and warranted was driven off the trailer with aired up tyres, towed the tow vehicle (and trailer) off the road and drove the rest (100km odd) of the way. Now late we rushed to get ready, scrutinized and started only to find it didn't climb, lost traction easily, struggled where it should walk through things and all morning and we could not figure out what was wrong...

During lunch break we parked beside another offroader and instantly saw the reason we were lacking traction, once we took 30PSI out of the tyres it was a very different story, we won some sections recovering to a reasonable score. Now just think if we had have started like that... Oh and after the weekend's competition we aired up the tyres and drove the offroader 400KM home!

For serious off-roading, it is a definite improvement over fully-aired rubber. However, once you are back on the road, aired down tires can be loud, wear unevenly and be right down dangerous. The risk of a tire coming off of it's bead increases with speed and with less internal pressure, the risk multiplies greatly. Therefore, it is essential to air back up when you are done four-wheeling, factor this time into your return trip and a stop at the garage to re-check them.

If you use a tire such as the Super Swamper that uses very large side lugs, it is most effective when aired down to 8 psi or lower. This allows the tire to conform to the terrain. Large heavy tires with large lugs dig into the terrain much better if they can get a larger "footprint" into what they are running on. This is attained easily with a drop in pressure.

Now comes the next big question. How low can I go? This is a big factor that is based on:

A. What terrain are you tackling?
B. Which tires and rims are you using?
C. What size/weight is your rig?

  • SNOW SAND and gravel: In snow, specifically snow that is packed and wet, you can air down safely to 12psi and if you struggle down to 8 psi. This will allow the footprint to expand and allow a great grip into the slippery terrain. With snow being slippery and dense, the tires will conform and help to compact it. This will also help others following behind you as a packed powder will be easier to traverse than one that is loose.
  • MUD: A lot of people think airing down in mud is a bad thing. Since tall thin tires tend to do best in mud, big sidewall lugs don't always help too much and you never know what is in there. This is your call but I wouldn't go below 20 psi here.
  • ROCK: This is essential. Huge sidelugs aired down can engulf rocks and let your rig move effortlessly over them. One lug can often catch the sides of a rock and pull you to safety. Some people prefer many small lugs here but I prefer fewer larger lugs aired down to 5-8 psi as they can usually hold you like to other combination and since you are traversing at such slow speeds, your bead should remain intact but the tyre can "slip" on the rim.

All these are estimates they can be different for each brand and style, also if you are running tubes then you run the risk of ripping out the valve if the tyre turns. You are the judge on the day and beadlocks (second air or mechanical) mean you can be more aggressive, personally I prefer mechanical bead locks (bolt on ones). 

I hope this helps you all in your airing down practices and tyre options, come in for a chat you never know we may have a trip, some tips on your particular brand of tyre or even an event or trip to tell you about where you can see what others do or even test out your tyre pressures for yourself!


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