With almost twice the torque of the GM14a, the GM22 298:1 Mini Sealed Metal Gear Motor is the most compact torque monster we have!
The GM22 mini metal sealed gear motor is the same form-factor of its siblings, but it has far more torque - almost twice as much as the GM14a at 3V! Did we mention it also has a sealed gearbox?
These also have a beefier set of mounting holes, threaded for M1.6 metric screws. Yes, it can a pain to find metric screws (sorry).
Offering 35.2 in*oz (2534 gms*cm) of torque at 3V, it's a real finger twister - ideal for high-torque solar-powered (or 2AA) applications. And with a sealed gearbox, it makes it ideal for building Turbot tumbling robots, which usually stir up all sorts of dust and grime.
These motors have an 8.7mm shaft length - check out the Specs for additional statistics, or the Resources tab for a downloadable PDF performance datasheet.