9 ft/sec for an 8" wheel drive?

[FrankJ]

Originally Posted by SerpentEagle

Right, but according to the motor curve, as you approach stall torque, speed in rpm decreases. Would momentum affect this? I.e. would it just be acceleration time that increases?

Also, what is gear spread? I hear people talking about this but I never understood this myself.

As you approach stall torque, your RPM approaches zero. Sort of by definition. Think of the wheels a rack & pinion. Effective gear ratio includes the wheel Dia and would be in distance traveled per motor revolution. With a low enough gear ratio you spin the tires and don't stall the motors. Before you spin the tires, a higher gear ratio has less pushing force. Once the wheels start spinning pushing force is limited by the dynamic Ce of friction. At stall, motor current is independent of gear ratio.

Gear spread only applies to multi speed gear boxes. It is the ratio of low gear to high gear. Since the wheels are a fixed diameter, they do not effect gear spread.

Momentum doesn't really come into these calculations. More of a conservation of energy.