Solarbotics GM12a 100:1 Mini Metal Gear Motor

Discontinuation notice: Please consider our micro metal gearmotors for a wide selection of alternative gearmotors with the same form factor (but longer output shafts).

These miniature brushed DC metal gear motors have 3 mm diameter output shafts that mate fairly well with any 1/8-inch hole output device, including the Solarbotics RW2 high-traction rubber wheels. Alternatively, you can use the Pololu universal mounting hub to mount custom wheels and mechanism to the micro metal gearmotor’s output shaft.

The brass faceplates have two mounting holes threaded for 1.7 (dia) x 0.35 (mm/thd) x 4mm long screws (M1.7 × 4 mm), or you can use our mounting bracket, which is specifically designed to securely mount the gearmotor while enclosing the exposed gears.

These small motors come in a variety of gear ratios, have a compact size (1.14" x 0.39" x 0.47"), and weigh only 0.29 oz, making them a great choice for small robot designs — and controlling these low-current motors is a snap with our qik 2s9v1 dual serial motor controller.

Solarbotics mini metal gearmotor dimensions (in mm).

You can download a pdf version of this drawing with imperial dimensions (119k pdf) or metric dimensions (118k pdf).

Specs for the Solarbotics mini metal gearmotors running at 6 V:

gear motor	gear ratio	free-run RPM	free-run current	stall current	stall torque	price
GM18	30:1	566	48 mA	500 mA	7.29 oz-in	$19.75
GM12a	100:1	170	48 mA	390 mA	10.70 oz-in	$19.75
GM13a	150:1	113	40 mA	370 mA	14.97 oz-in	$19.75
GM14a	298:1	71	50 mA	533 mA	30.70 oz-in	$19.75

Specs for the similar, less expensive Pololu metal gearmotors running at 6 V:

gearmotor	gear ratio	free-run RPM	free-run current	stall current	stall torque (oz-in / kg-cm)	price
5:1 Micro	5:1	2450	50 mA	360 mA	1 / 0.1	$19.95
10:1 Micro	10:1	1250	40 mA	360 mA	2 / 0.2	$19.95
30:1 Micro	30:1	440	40 mA	360 mA	4 / 0.3	$19.95
50:1 Micro	50:1	250	40 mA	360 mA	6 / 0.4	$19.95
100:1 Micro	100:1	120	40 mA	360 mA	10 / 0.7	$19.95
150:1 Micro	150:1	85	40 mA	360 mA	15 / 1.1	$19.95
210:1 Micro	210:1	60	40 mA	360 mA	19 / 1.3	$19.95
250:1 Micro	250:1	50	30 mA	360 mA	22 / 1.6	$19.95
298:1 Micro	298:1	45	30 mA	360 mA	25 / 1.8	$19.95
5:1 Micro HP	5:1	6000	120 mA	1600 mA	2 / 0.1	$19.95
10:1 Micro HP	10:1	3000	120 mA	1600 mA	4 / 0.3	$19.95
30:1 Micro HP	30:1	1000	120 mA	1600 mA	8 / 0.6	$19.95
50:1 Micro HP	50:1	625	100 mA	1600 mA	15 / 1.0	$19.95
100:1 Micro HP	100:1	315	80 mA	1600 mA	25 / 1.8	$19.95
150:1 Micro HP	150:1	200	70 mA	1600 mA	45 / 3.2	$19.95
210:1 Micro HP	210:1	140	70 mA	1600 mA	65 / 4.7	$19.95
250:1 Micro HP	250:1	120	70 mA	1600 mA	75 / 5.4	$19.95
298:1 Micro HP	298:1	100	70 mA	1600 mA	90 / 6.5	$19.95
24:1 Mini	24:1	410	70 mA	420 mA	4 / 0.3	$14.95
100:1 Mini	100:1	140	90 mA	800 mA	15 / 1.0	$17.95
35:1 Mini	35:1	350	70 mA	1500 mA	35 / 2.5	$17.95
25:1 20Dx44L mm	25:1	500	160 mA	3300 mA	20 / 1.5	$19.95
19:1 37Dx52L mm	19:1	250	170 mA	2500 mA	40 / 2.9	$24.95

Note: These gearmotors do not come with mounting hardware, instructions, or packaging. The brass faceplate has two mounting holes threaded for 1.7 (dia) x 0.35 (mm/thd) x 4mm long screws (M1.7 × 4 mm), and our micro metal gearmotor bracket (sold separately) gives you even more mounting options.

People often buy this product together with:

Solarbotics RW2 Wheel (external set screw)