When and why should I air down my tires? Will the tire come off the rim if I release too much air?
A: Airing down can help you gain traction, but airing down isn’t necessary for most off-roaders. Your recommended highway inflation pressures will perform nicely, both on the pavement and during off-road excursions, all without having to fiddle with tire pressure.
On the upside, what you can expect from airing down is a smoother off-road ride and better traction, mostly on rocks, sand and snow.
On the downside, you have to go through the trouble of airing down and then airing up again. You will need to buy some sort of portable air compressor or storage tank. When your tires are aired down, you will lose ground clearance, and you also run the risk of damaging your tires and rims.
If your rig has conventional wheels, you will have to do some experimentation to see what works best on different terrains. A good rule of thumb is to never air down below 15 pounds per square inch (psi) without beadlocks.