Pololu 187 - Solarbotics GM8 143:1 Gear Motor Offset Output

This 143:1 gearmotor (gearbox with brushed DC motor) is a faster version of the GM2 gearmotor. It is a great low-cost alternative to modified hobby servos or Tamiya gearboxes. The low-current motor is a perfect match for our qik 2s9v1 dual serial motor controller, and the compact size makes this unit an attractive choice for small robot designs.

This gearmotor comes pre-assembled, with the gears fully enclosed. There are built-in mounting holes, and the output shaft is 7 mm in diameter with two sides flattened. Please note that the output shaft is slightly shorter than on the GM2 and GM3 gearmotors. Also, the green end of the output shaft should not be used (it is difficult to get to, anyway). This motor also comes with a built-in safety clutch.

Compatible products include a custom-molded GMPW plastic wheel, and the Solarbotics GMW motor mount, which can be used as a wheel itself or as a mounting point for other wheels or mechanisms. A mounting bracket is not required but can be purchased separately for more versatile installation.

For similar gearmotors, you might want to take a look at:

• Less expensive: Pololu 120:1 plastic gearmotor offset output
• Higher torque: GM2 gearmotor
• 90 degree output shaft: GM9 gearmotor
• Smaller: GM6 gearmotor

To increase the power of this gearbox, you can replace the motor with a higher-power RM2 motor. For a replacement motor, see the RM3 motor.

Specifications

• Description: Offset/inline
• Gear ratio: 143:1
• 3 V Operation:
  • No-load RPM: ~ 40
  • No-load current: ~ 50 mA
  • Stall current: ~ 400 mA
  • Stall torque: ~ 44 oz-in
• 6 V Operation:
  • No-load RPM: ~ 78
  • No-load current: ~ 52 mA
  • Stall current: ~ 700 mA
  • Stall torque: ~ 76 oz-in
• Weight: 32 g

Solarbotics GM8 gearmotor dimensions (in mm).

You can download a pdf version of this drawing with imperial dimensions (118k pdf) or metric dimensions (117k pdf).

Though the product picture shows two gearmotors, this product is for a single motor.

People often buy this product together with:

Tamiya 70144 Ball Caster Kit (2 casters)

Solarbotics GMPW-R Red Wheel

Solarbotics GMB28 (GM2/GM8 Gear Motor Bracket, Laser-Cut Steel)