The first in Tamiya’s “high efficiency” series, the planetary gearbox features two 4:1 and two 5:1 stages that can be combined in any way you like—you can even combine two kits to get really huge gear ratios. The output is always conveniently on the same axis as the motor shaft. Available gear ratios are 4:1, 5:1, 16:1, 20:1, 25:1, 80:1, 100:1, and 400:1.

Tamiya 72001 planetary gearbox dimensions (in mm).

The low-voltage motors in the planetary gearbox run on 3-6 volts and draw up to a few amps, making them perfect candidates for the DRV8833 motor driver carrier. Motor overheating can be caused by excessive stalling, even at very low voltages. We recommend that you use stall-detection sensors, or just watch your robot, to make sure that it doesn’t stall for more than a few seconds at a time.

This gearbox has a 4 mm diameter, round output shaft, which works with the wheels that are compatible with Tamiya 4 mm, round shafts. Our 3 mm universal mounting hub also fits on the smaller threaded end of the shaft, although it is not specifically intended to work with this type of shaft (the hub’s set screw could damage the thread on the shaft).

For motor specs, see the Mabuchi motor RC-260 (#2295) data sheet (60k pdf).

General specifications

Typical operating voltage:	4.5 V
Gear ratio options:	4, 5, 16, 20, 25, 80, 100, 400 :1
Free-run motor shaft speed @ 3V:	6800 rpm¹
Free-run current @ 3V:	130 mA²
Stall current @ 3V:	2.5 A
Motor shaft stall torque @ 3V:	1.2 oz·in³

Notes:

1 A theoretical speed of the gearbox output shaft can be computed by dividing this speed by the gear ratio.

2 This is the no-load current of the motor when disconnected from the gears in the gearbox; the no-load current of the entire gearbox with the motor connected will be slightly higher and will vary depending on the gear ratio.

3 A theoretical torque of the gearbox output shaft can be computed by multiplying this torque by the gear ratio.