SEE PHOTO FOR A REPRESENTATION OF THE DIFFERENCE AIRING DOWN MAKES TO YOUR TIRES AND TRACTION PATCH: (Result may vary)
We often air down to very low pressures for deep snow wheeling in the winter. The longer tread patch helps keep us on top of the snow by better distributing the weight of the vehicle. However, we also air down a good amount for summer trails, just not as much. As you will see, there are a number of benefits to airing down, even when traction is not the primary issue.
Let’s face it, we all grew up being told that having your tire pressure below 30 pounds or so will result in some kind of tire catastrophe, but now you are being told to run considerably lower than 30 pounds of tire pressure. Just to be clear, bead locks are nice to have, however, very few of us have them and they are not needed for the pressures I am speaking of here. I am speaking about using pretty much standard, everyday wheels, and off-road-ready tires though some combinations are better than others. For instance, wide-for-tire wheels are more likely to have the tires come off the bead at lower pressures.
Of course, we are not talking about running these lower pressures on paved roads or at any kind of normal road speeds. This is about off-pavement driving at slow speeds. Caution and common sense are ALWAYS appropriate. Remember, I can only share my experience. YOU have to make the final call on what is right for you and your rig.
The trails, in the area of Montana I usually wheel on, are mostly rock based. At full tire pressures, these rough roads will pretty much beat the crud out of you, your passengers and your vehicle. A suspension soft enough to smooth these roads out would be useless at on-road speeds.
So we give the suspension a bit of help by making the tires softer. I and those I wheel with will lower the pressure in our 35" tires to 14-16 pounds. This makes the tires soft enough to make the roads more tolerable yet still stiff enough to handle reasonable trail speeds. Some with larger (or stiffer) tires will go lower and some with smaller tires will need to stay at a little higher PSI, in general.
Remember that a specific tire pressure's effects will change with tire size. A pressure of, say, 12 PSI may be fine off-road for a 37" tire, but may be way too low for a 28" tire. So you may need to play with your pressures to find the best one for your tires, vehicle, and trails.
These lower pressures will aid with traction both by the resulting larger contact patch of tread on the ground but also by allowing the tire to form to the road/rock surface.
