[ChuckMcM]

Thanks for the links, I figured that the lack of compliance in the "tire" section of the wheels would be an issue but that is a bit more damage than I would expect. I am guessing that under some driving conditions you might get up to 50% of the rover weight on a wheel and if that was while the wheel was rolling over a rock, the tendency would be to cut into the aluminium. So one wonders why not titanium outer rims? or a compliance system that would allow the wheel to deform until enough weight had been distributed across enough surface area to keep it under the 'minimal damage' threshold.