What Goes Up, Should Come Down
…or vice-versa, when it comes to tire pressure. One could call tire pressure control “the poor man’s winch”, since lowering tire pressure tends to elongate its contact patch or footprint on the ground. That increase in gripping surface area increases traction on difficult surfaces. Airing down tires in off-road situations is old hat to 4WD enthusiasts, but new to me. It is considered at least as effective as jamming traction boards under the tires, if not more so.
I normally wouldn’t consider it because of its drawbacks:
- While you’re airing down or pumping tires back up, you can be sitting beside the road for considerable periods of time.
- If you hit a perfect patch of ground for making time in the middle of badness, you cannot pick up the pace on it to gain time – going too fast on a deflated tire can cause overheat and handling issues.
- Heavy vehicles on high-pressure tires benefit less from lowering pressures – but do still benefit.
- Play Baja Racer, and the doughball handling can put you in a ditch or over an embankment, pronto.
- Go too far with lowering pressure, and you can unseat the tire bead, effectively dismounting the tire.
- There is a risk on rocky ground of compressing a sidewall enough to pinch it, resulting in damage or puncture.
- Overall, operating a vehicle on underinflated tires is a direct trade: increased traction in trade for increased odds of tire failure or vehicle mishap.
I have to admit, I’ll occasionally be lowering my tire pressures not to conquer new trails, but as a last desperate act when I’ve underestimated a trail’s traction difficulty or roughness. Roughness? Yes, and I’m not talking about climbing over grapefruit-sized rocks. Idling over Read more…