The pinion is more kinda like a clutch bell setup - the 'clutchbell' itself is attached to the motor shaft with a grub screw...

Then the stock LST pinions (from the original nitro clutchbell) just screw straight onto the newly designed (by Mr C) 'clutchbell' assembly, just as they are screwed onto the nitro clutchbell :)

I also have 2 other pinion gearing combo's i can run... the teeth on each pinion are 4+ and 6+ more than the stock pinions :) I had these made up a few months ago in a group buy on an aussie forum :)