The gear tooth strength FAQ answer points out that although the gears get stronger as they get bigger, even the smallest 12 tooth gear is stronger than the torque rating of the square center hole. Also that once the center hole get stripped, its torque rating drops significantly.
Here are some potential workarounds for this problem:
- stack multiple gears side by side to spread torque between them
- For all but the smallest 12tooth gear, you can reinforce the gear with the metal locking bar, or a circle cut from the flat plate. These can be screwed through the gear to greatly increase the square hole torque rating.
- similarly, you can a set-screw collar can be screwed to the gear.
These same ideas should work for wheels as well as gears as well.
These ideas should be competition legal, if kit screws and other materials
are used for the attachment.