Although Bob had not done any walking on salt lakes he
had tried his cart out on the tracks near his home. As a
result of this, and reading Warren Bonython's book on crossing
the Simpson, he became obsessed with punctures. Notice the
blue "prickle removers" that sit over his tyre.
He also had very thick tyres and was carrying some blue
gue that you can put in tubes so that holes are blocked
when they as they are formed.
Bob never got a puncture and we agreed that this was the
result of his thick tyres.