The Rover 5 uses 4 independent motors, each with an optical quadrature encoder and gearbox. The entire gearbox assembly can be rotated at 5 degree increments for different clearance configurations. You can even replace the tank treads with traditional wheels.

This isn’t a wimpy or flimsy robot base. Weighing in at over 2.5 pounds without batteries, this base is heavy duty and can drive over quite a bit. Check the manual below for dimensional drawings.

Features:

• Completely adjustable gear box angles for each motor
• 4 individually controlled DC Gear motors
• 4 independent optical encoders
• Thick rubber tank treads
• 6 x ‘AA’ battery holder (total of 7.2V for rechargeables & 9V for Alkaline)
• 10Kg/cm stall torque per motor
• Suppression coils attached to each motor
• Replaceable hubs for swapping with wheels

Documents:
Quadrature Encoder Example