Pololu 6V 25:1 20D Metal Gearmotor (Long-life Carbon Brush)

PololuSKU: POL-3700
Sale price £19.10
incl. VAT
excl. VAT
Only 10 units left

Awesome Extras

PololuPololu 20D Metal Gearmotor Bracket Pair
Sale price £7.70 incl. VAT excl. VAT
Pololu12mm Hex Wheel Adapter for 4mm Shafts (2-Pack)
Sale price £4.90 incl. VAT excl. VAT

These small brushed Pololu 20D DC gearmotors can deliver a lot of power for their size. This version has a 6V brushed DC motor with long-life carbon brushes combined with a 25:1 metal spur gearbox. The gearmotor is cylindrical with a diameter of 20mm, and the D-shaped output shaft is 4mm in diameter and extends 18mm from the faceplate of the gearbox.

In general, these kinds of motors can run at voltages above and below their nominal voltages; lower voltages might not be practical, and higher voltages could start negatively affecting the life of the motor.

We also stock 100:1 and 250:1 versions of this motor.

Note: Stalling or overloading gearmotors can greatly decrease their lifetimes and even result in immediate damage. In order to avoid damaging the gearbox, we recommend keeping continuously applied loads under 5 kg-cm (75 oz-in). Stalls can also result in rapid (potentially on the order of seconds) thermal damage to the motor windings and brushes, especially for motors like this that can deliver a lot of power for their size; a general recommendation for brushed DC motors is to limit continuous current to approximately 25% of the stall current.


Voltage 6V
Gear ratio 25:1
No-load speed @ 6V 570 rpm
No-load current @ 6V 0.15A
Stall current @ 6V 2.9A
Stall torque @ 6V 1.6 kg·cm
Max output power @ 6V 2.3W
Extended motor shaft? N
Long-life carbon brushes? Y
Motor type 2.9A stall @ 6V CB (carbon brush)
Size 20D × 43.2L mm
Weight 44g
Shaft diameter 4mm

Performance at Maximum Efficiency

Max efficiency @ 6V 33%
Speed at max efficiency 440 rpm
Torque at max efficiency 0.33 kg·cm
Current at max efficiency 0.74A
Output power at max efficiency 1.5 W



The downloadable diagram shows the dimensions of the 20Dmm line of metal gearmotors (units are mm over [inches]).

Warning: Do not screw too far into the mounting holes as the screws can hit the gears. We recommend screwing no more than 3.5 mm (0.14″) into the M2.5 mounting holes.

Gearmotor accessories

  • Gearmotor Face Plate - The gearmotor face plate has two mounting holes threaded for M2.5 screws, and you can use our custom-designed 20D mm metal gearmotor bracket to mount the gearmotor to your project via these mounting holes and the screws that come with the bracket.
  • Universal Mounting Hubs - The 4mm diameter gearbox output shaft works with Pololu universal aluminum mounting hub for 4mm shafts, which can be used to mount our larger Pololu wheels (60mm-, 70mm-, 80mm-, and 90mm-diameter) or custom wheels and mechanisms to the gearmotor’s output shaft.

  • Scooter Wheel Adaptors - You can use our 4mm scooter wheel adapters to mount many common skateboard, inline skate or scooter wheels to the gearmotor’s output shaft.

  • 12mm Hex Wheel Adapter - For a general-purpose hex adapter, consider our 12mm hex wheel adapter, which lets you use this motor with many common hobby RC wheels.
  • Wild Thumper Wheels - These motors also work with the hex adapters included with the 120mm-diameter Wild Thumper wheels

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