simple engineering question

[Ben Mitchell]

I'm working on a LEGO Mindstorms bot, and I have two motoers using 12tooth bevel gears to use one output shaft to turn two, wich in turn turn tow more, which move the wheels (in essence: one moter per two wheels.

I'm mounted a claw, which is powered by a geabox, but i need more torque in the drive system. I was thinking of improving the ratio from 1:1 (12t to 12t) to 1:3 (8:24) but i have a 12t bevel on the same shaft as the 24.

my question is this: is there a formula for finding out the gear ratios of gears on different shafts, when a third gear to being powered by the first?

Think of it as an 8t gear, driven by a motor, turning a 24t gear, turning a sahft with a 12t bevel. How much torque am i getting? is there a formula out there? I've looked all over the 'net, and can't find a thing. Thanks.

--Ben Mitchell