From Wikipedia:

> Wheels and tires retracted into housings where they were heated by engine exhaust gases. This was to prevent low-temperature cracking of the natural rubber compound. Long front and rear overhangs on the body were to assist with crossing crevasses up to 15 feet (4.6 m) wide. The front wheels were to be retracted so the front could be pushed across the crevasse. The front wheels were then to be extended (and the rear wheels retracted) to pull the vehicle the rest of the way across. This process required a complicated, 20-step procedure.