What is a good gear ratio?

I have a comp next week and currently have a drivetrain gear ratio with blue carts that doesn’t have enough torque, I need a good gear ratio that can have a good amount of torque and speed for a heavy robot.

have you tried carts with more torque


No. I have been trying to use blue for speed but when we go up the platform we can’t make it with all of our weight and the weight of 2 MG

maybe it’s not speed you need, but torque.


Yes! Any good gear ratios suggestions for me? Someone gave me an idea of a 5:7 gear ratio with blue carts

if you can’t answer this question by yourself, just do green direct


you’re aiming for a far too fast ratio.

the absolute simplest working ratio on 3.25" or 4" wheels will be direct drive to 200 rpm motors (the green cartridges).

depending on the weight of your robot, assuming you’re using 4 motors on your drive, the types of ratios you want to be considering for 4" wheels are:

100 rpm motors on a 7:3 ratio (233 rpm)
600 rpm motors on a 3:7 ratio (257 rpm)
200 rpm motors on a 7:5 ratio (280 rpm)

and for 3.25" wheels some good ratios are:

200 rpm motors on a 7:5 ratio (280 rpm) (a bit difficult to do considering 84t gears are larger than 3.25" wheels)
200 rpm motors on a 5:3 ratio (333 rpm)
600 rpm motors on a 3:5 ratio (360 rpm)

it would be pretty difficult to get a good ratio on 2.75" wheels this year, so I wouldn’t recommend using them.

if you aren’t comfortable with drive ratios though, direct 200 rpm is always a safe and reliable bet.


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