PLEASE like (or leave a comment what is wrong so I can fix it)
This is a Traxxas Slash 2WD 28-tooth roughly 48p pinion gear. I used it with the 67 tooth spur gear (posted by me on Thingiverse) and the speed was incredible. Take it easy with the throttle to avoid stripping the gears. Thanks and enjoy. This part is posted AS IS with no warrantee - use at your own risk.
You might need to drill out some of the holes just slightly for this to work. It's difficult calculating how much the PLA is going to expand. 4% is my guideline.