# TT motor vs N20 gearmotor for small robots

> TT motor vs N20 gearmotor for small robots: size, stall current, shaft and driver needs, and why listed specs disagree. From vendor and Pololu pages.

Canonical: https://roboticsengineering.in/tt-motor-vs-n20-gearmotor-small-robot/ | Published: 2026-11-04 | Updated: 2026-11-04 | Author: jaadudigital

**The yellow TT motor is cheap, big and easy to mount; the N20 gearmotor is small, can be quick or strong depending on the gearing, and is the usual choice when space is tight.** This guide compares them on size, current, torque and driver needs, and shows how to check the figures on the listing you are about to buy.

*Status: written from vendor and Pololu listings. We have not bench-tested these motors, so no speed, torque or run-time results of our own appear here. Listings for the same motor name vary widely, which is the main point of this guide.*

## The short comparison

|  | TT gear motor (yellow) | N20 / micro metal gearmotor |
| --- | --- | --- |
| Body size | About 68 to 70 mm long, roughly 18 to 22 mm across (listings differ) | Gearbox cross-section 10 × 12 mm in the Pololu family |
| Typical supply | 3 to 6 V | Varies by version: 6 V and 12 V versions exist |
| No-load current | About 150 mA, up to 200 mA at 6 V on some listings | Roughly 80 to 150 mA on Pololu’s high-power versions, depending on voltage |
| Stall current | Sources disagree: about 1 A to 1.5 A at 6 V | Pololu lists 1.6 A at 6 V for HP, 750 mA at 12 V for HPCB 12 V |
| Shaft | Usually double-sided and flatted, around 5 to 5.5 mm | 3 mm D-shaped output shaft in the Pololu family |
| Best for | Beginner chassis, simple two-wheel cars | Small line followers, mini sumo, compact builds with encoders |

The N20 name is the common market name for the 10 × 12 mm gearmotor size. Pololu sells the same size family as “micro metal gearmotors” and publishes the most complete figures, so its numbers are used here as a reference. Clone motors sold as N20 may differ, so treat them as a guide to what to look for, not a promise.

## Why the listing numbers disagree

For the TT motor, Adafruit measured about 1.1 A stalled at 3 V and 1.5 A at 6 V, while another retailer measured 0.5 A at 3 V and 1.0 A at 6 V. Speeds are quoted as 90 RPM at 3 V and about 200 RPM at 6 V on some pages, and 125 RPM at 6 V on others. Even the body length differs by a couple of millimetres between sellers. The motors are sold by many factories, so the listing in front of you is the only source for the motor you will actually receive. Plan the driver and battery for the highest stall figure you see.

## How to choose

- **Space first.** If the chassis is large and you want easy mounting holes, the TT motor is simpler. If the robot must be a few centimetres wide, only the N20 size fits.
- **Torque and speed together.** N20 motors come in many gear ratios. A low ratio is fast and weak, a high ratio is slow and strong, so pick the ratio from the speed and load you need. The [motor selection guide](https://roboticsengineering.in/motor-selection-for-robots/) shows how to estimate torque.
- **Voltage.** Match the motor’s rated voltage to your battery. A 6 V motor on a 2-cell pack is a common pairing; a 12 V motor needs a 3-cell pack or a boost, see the [battery guide](https://roboticsengineering.in/robot-battery-guide/).
- **Encoders.** Some N20 motors come with a magnetic encoder on the back shaft. For closed-loop speed control read the [wheel encoder guide](https://roboticsengineering.in/robot-wheel-encoder-guide/).
- **Driver current.** The driver must handle stall current, not the running current. See [L298N vs TB6612FNG](https://roboticsengineering.in/l298n-vs-tb6612fng/).

## A practical current rule

Pololu recommends keeping brushed motor operation at 25 percent or less of the stall current for long life. Applying that to a motor with a 1.6 A stall figure gives about 0.4 A as a comfortable running current. That is an illustrative use of the rule, not a measurement of any motor you buy. Measure your own current with a multimeter or the [INA219 monitor project](https://roboticsengineering.in/projects/robot-battery-current-monitor-ina219/).

## A test plan before you commit

- Run each motor free at your battery voltage and record the no-load current.
- Hold the wheel by hand (briefly) and note the current rise, or use a short stall test within the driver’s rating.
- Time the robot over a fixed distance at a fixed duty cycle and compare it with the speed you need.
- Check both motors in a pair spin at the same speed at the same PWM; if not, see [the motor mismatch fix](https://roboticsengineering.in/fix/robot-drifts-to-one-side-motor-speed-mismatch/).
- Photograph your own set-up and record the real numbers. That is the part no datasheet can supply.

*Sources: Pololu micro metal gearmotor category and product pages; Adafruit TT motor product page and data sheet; retailer listings from RobotShop, BC Robotics and Grobotronics. Last reviewed November 2026. Written, checked and maintained by Jignesh Panchal.*