Originally Posted by DKP
I have no idea why the pressure was so high. I checked it using the pressure gauge at a local gas station (they even charged me for the air!) before we left on the trip and all tires were at 34 psi. I am now wondering if the pressure gauge built into the air pump was inaccurate.
The damage is indeed that narrow strip where the tread meets the sidewall. You can just sort of see the different colours of rubber where the wear is particularly bad. Running my hand over this area I can feel the uneven surface (hence the vibration while driving, I suspect.)
Pressure gauges at servos are unreliable, although some of the digital models with the centrally-located gauge seem to be OK. I have a good quality gauge that I trust.
In one post, you stated that you had regularly swapped-around the tyres. I wonder if this is part of the problem, particularly if the swap is across-sides and this means reversing to direction of rotation. The tyre flexing from the bad camber and reversal would provoke excessive wear.
I try to keep the tyres rotating in the same direction and only swap them every 20,000 km.