MG321T/0.5M 21T Motor Gear 40Cr Steel Pinion for RC Motors by GPM  [MG321T/0.5M]

The GPM MG321T/0.5M motor gear is a small-profile pinion intended for scale RC drivetrains needing a 21-tooth pinion with a 0.5mm module. It uses 40Cr steel with a hardened black surface treatment to resist wear better than non-hardened replacements.

Check the supplied dimensions to ensure compatibility: 21 teeth, 0.5mm module, and a motor tooth diameter of 3.175mm with a round bore. The gear secures to the motor shaft with two 3x3 set screws, so confirm your shaft type and pinion spacing before fitting to avoid mesh problems.

In practice this pinion is suitable for straightforward replacements and mild tuning changes: matching module and tooth count keeps mesh predictable, the hardened steel helps prevent premature stripping, and the round bore with dual set screws makes alignment on typical motor shafts quick.