Originally Posted by
KerryIrons
Not really debatable. Tire wear (scrubbing of rubber from the tire) is due to the force applied from pedaling. There is a tiny amount of wear from braking forces, but a front tire will die of old age long before it loses enough rubber to be worn out. Since, for a given rider, pedal force on the tire is consistent, lower pressure means a larger contact patch means less scrubbing force per unit area means slower tire wear. Basic physics combined with basic material properties.
Of course it is debatable. But maybe not if you are only focusing on the tread wear side of overall picture.
I tend to think that with a tire operated at low pressures, giving a much wider contact patch that the sidewall of the tire where that contact patch bulges will be exposed to more gravel and debris laying on the trail. But maybe not. I've not really seen a good cross section view of how that bulge really looks.