This 143:1 gear motor is much like the GM3 gear motor but runs at nearly twice the speed. Great for robots needing speed over torque!
The GM9 is much like the GM3 gear motor but runs at nearly twice the speed.
Do you need to mount something to the shaft of the motor? Although it doesn't work as well as other motors because of the GM9's shorter output shaft, the GMW is a solid platform for a variety uses. Alternatively, you'll also find that a #2x1/4" SMS screw will provide a snug fit for your need.
(Motors are sold individually, wheels are not included)