Tread
From FIRSTwiki
Treads are a method of robot locomotion and are occasionally used in place of wheels.
Treads are used on a "tank drive," which is a variation on the four-wheel drive train that resembles a military tank. Treads are generally rubber belts attached to either sprockets or to wheels and are thus driven that way with the belt itself providing traction along the ground. Tank-driven robots tend to lack maneuverability in terms of navigating curves, but have zero turn radius. While treads tend to be very rugged, they are also very hard to repair in the event of damage or maintenance.
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