These are the 30:1 gearboxes that have been well proven in our High-Temp Hardened Shaft (HTHS) 1400rpm N20 motors.
Installed in our motors they will have the below rpms on 2S:
N10 - 1200rpm
N30 - 1000rpm
These "replacement" gearboxes include the 2 mounting screws and the pinion gear.
*** Installing these gearboxes on any motor OTHER than the Turnabot HTHS 1400rpm N20 motors will require removing the original pinion gear and installing the included pinion gear.
The "right" way to remove the pinion gears is with a proper micro gear puller. (available on Amazon)
The "right" way to install the gears is with an appropriate press or vice with fixturing.
That said, AT YOUR OWN RISK, it "can" be done with TWO micro screwdrivers (if you use one you're almost guaranteed to bend the shaft), any type of compression device that keeps the jaws parallel, such as Knipex or a vice with flat jaws, and something to support the small silver disk in the black plastic caps, such as an M2 machine screw. You'll also need something to allow the shaft to press slightly beyond the end of the gear, the screw holes in the old gearbox can be used in a pinch.
Below are instructions with pictures of a worst-case scenario (unexpectedly at a competition for example) "hack" option for replacing gearboxes.
With a micro-screwdriver remove the 2 screws holding the gearbox on.
Use TWO tools to EVENLY pry the gear off of the pinion (again, using one is nearly guaranteed to bend the 1mm shaft):
You can usually set the gear into position with your fingers. One side of the gear may slide on a bit more than the other.
You may find it much easier to attach the machine screw to the compression device as close to edge as possible. It can be done with tape like this:
You can GENTLY press the gear flush to end of the shaft with the Knipex:
That will only get the gear to end of the shaft like this:
In order to get it all the way on you'll need to use something like the screw hole in the old gearbox:
That will let you get the gear SLIGHTLY past the end of the shaft like this:
You can see in the below 2 pictures how the pinion gear is now centered on its mating gear:
Brushed Motor Basics (Torque & Stall Current)
In brushed motors, torque and stall current are closely related—as one increases, so does the other. This makes stall current a useful way to compare motor strength across different designs.
Below are typical stall current ranges on 2S LiPo for common N-series motors and what that means in real-world robot performance.
Cheap N20 Motors
(often ~$4 each)
Typical stall current: ~0.25 A
Real-world performance:
These motors struggle to move a 150 g robot effectively and generally cannot push an additional 150 g load. They are very weak, and their low stall current reflects this.
Decent N20 Motors
(usually $7–$9 each)
Typical stall current: ~0.45 A
Real-world performance:
These motors can move themselves reasonably well but offer limited pushing power and are unlikely to perform well in competitive pushing situations.
“Good” N20 Motors
(usually $10–$14 each)
Typical stall current: ~0.90 A
Real-world performance:
These motors have noticeable authority in 150 g robots and are sometimes used in 1 lb bots, depending on the drivetrain.
High-End N20 Motors (Pre-Turnabot)
(typically $18+ each)
Rated stall current: ~1.60 A
Real-world performance:
Previously considered the best available N20 motors, with cost reflecting their higher performance.
Turnabot N20 Motors
Typical stall current: 2.0+ A on 2S
Real-world performance:
These motors deliver exceptional torque and are very difficult to stall in typical insect-weight drivetrains. Running one Turnabot N20 per side on 2.0 A ESCs has proven reliable.*
* Important: Most 2.0 A ESCs cannot run two Turnabot N20 motors per side.
This includes the standard Malenki Nano. However, the Malenki High Voltage, while rated at 3.5 A per channel, typically tests at just over 4.0 A, making it an excellent match for two Turnabot N20 motors per side.
Turnabot N10 Motors
Typical stall current: 1.0+ A on 2S
This 1.0 A nominal stall current aligns well with running two N10 motors on ESCs rated for 2.0 A max.
Despite their smaller size and lower weight, Turnabot N10 motors are more powerful than most N20 motors on the market.
Real-World Traction and Power
Even the 3600 RPM N10 motors have enough torque that, with:
Four of the stickiest tires available
A 2S LiPo at its minimum recommended voltage (7.4 V)
While carrying another 150 g robot (≈300 g total on the wheels)
…the motors will still spin all four tires.
Lower-RPM variants can spin four sticky tires even in 1 lb robots.
Important Warning
This level of power in such a small motor means these motors must not be stalled for extended periods. Prolonged stalling will damage any brushed motor, regardless of quality.
Key Takeaway
Not all “N20” motors are the same
N10 motors are smaller and lighter than N20 motors
Turnabot N10 motors outperform most N20 motors
Stall current tells the real story—and Turnabot motors are built at the extreme end of what these sizes can deliver.