OpenRC truggy gear box: the gears

with this design, openrc truggy could achieve following feature:

* motor quick assemble/disassemble by 2 screw
* gear ratio from around 8.4 to 13, selectable
* reduce motor heat
* much more stronger motor gear design, it really broken
* then you won't need to buy a metal motor gear for the truggy.

final ratio 13 means truggy could drift in the dust...

i like this design myself, -:)

note:

*co-operate with gear box who hold these gears
http://www.thingiverse.com/thing:8288