Good quality 48 pitch 3mm aluminium pinion gears in the most common sizes.
Terminology
Pinion: The smaller gear which goes on the motor.
Spur Gear: The larger gear which goes on the gearbox or drivetrain.
Sizing
48 Pitch: The gap between each tooth, check this matches your spur gear.
3mm: The size of the hole, check this matches your motor shaft.
Gearing
Smaller Pinion/Larger Spur gear: Lower top speed, higher acceleration, lower motor temperature.
Larger Pinion/Smaller Spur gear: Higher top speed, lower acceleration, higher motor temperature.
-Motors may be geared according to desired performance, maximum gearing must be determined according to motor temperature.
-A safe maximum of 65c under worst case conditions is recommended to avoid motor damage.
-Conditions that may contribute to the highest motor temperature include: high ambient temperature, high tyre grip,
heavy and repeated acceleration and breaking, off road environments particularly grass and mud.
Installation
-Gear
mesh must be set correctly to avoid damage particularly to plastic spur
gears. There must be a small gap in the mesh between each gear.
The gap should be just enough that the gears run smoothly and play can be felt when moving either gear by hand.
-Low
strength thread-lock must be used on the grub screw. Use heat from a
soldering iron to deactivate threadlock before removal.
-Use of Hex-Plus bits/drivers to avoid stripping out grub screws is recommended.
-Where
a grub screw strips out, remove motor and use a punch to gently and
slowly hammer out motor shaft whilst supporting pinion in a vice.
Notes
-Appearance may vary from picture, does not affect functionality.
-If the size you require isn't listed, consider changing your spur gear to allow use of a more common size.
-The smaller 13t-15t sizes are difficult to manufacture as there is very little material, therefore the teeth have a thicker curved profile at the grub screw end. The pinion must be positioned correctly so that the teeth on the spur gear mesh with the pinion at the point before the thickness of the teeth increases, otherwise it will wear out the spur.