Transmission gear ratio

I searched already…does anyone know the gear ratio on the kit transmission?

I did a rough calculation yesterday and got a 1:17 gear ratio.


The transmission is a 12.75 : 1 gear ratio, the sprockets are a 28:21 gear ratio, this combines for a 17:1 gear ratio.

The Guidelines document has a lot more info on the transmissions and motors you may find useful. Look for it around pages 7, 8, and 9.

It is exactly (50/14)*(50/14), or 625/49 which approx. equals 12.7551:1.

This is in the kit transmission manual located here. Right click on “FIRST 2005 Transmission Manual -RevA” and select “save target as”.


thanks guys…does anyone know the size of the gear box witht eh motors attached??

big and heavy

These are just estimates, but probably 4.5"-5" depth on the gearbox and 5-7lbs.