Axial 32P Pinion Gear w/3mm Bore (11T)

Deceiving product description. It is for 3.175mm axle and NOT for a 3mm axle. Installed in a 3mm axle gets wobbly and jams gear.

This pinion will not work correctly on a TRX-4 so don't make the same mistake as I did. Since the TRX-4 OEM pinion was out of stock for a while and because some forums lead to believe any 32P gear would work I got this Axial pinion. Although this may be true in terms of gear meshing compatibility, in my case, the overall pinion design mainly it's collar length caused meshing issues.

In my case the pinion collar (non gear side) is a little bit too long and the gear machining a little too short. Installing the pinion hard against the motor still causes spur gear to collar interference so much so there is excessive meshing noise. To make it compatible you would have to move the motor mount and the spur gear apart about 1mm or extend the machining of the pinion gear further in on the collar. It is that close to make it work but I my opinion your better off getting (waiting) for the OEM part. I have now replaced mine with an TRX-4 OEM part and it works without noise.

Now some may think just reverse the pinion. This I tried but now causes other issues like clearance with the motor housing on the other end. This collar is just a bit too wide and rubs within the motor housing recess. Also the Holmes Hobbies motor that I used has a shorter shaft so the set screw becomes the limit to how far you can move the pinion out to make it mesh.

I gave the rating a 4 star since it may work well in Axial rigs as it was intended and this review is only provided for others that may think this Axial pinion is compatible with the TRX-4.