HELP WITH VEX

[Chris is me]

There isn't actually a way to get a 10:1 ratio in Vex with just gears. You can only get combinations of 1, 3, 5, and 7 (12, 36, 60, 84).

I've heard as a rule of thumb, a good ratio for 4" wheels on both sides of the ball with 2 motors per wheel is 49:3, which can be achieved with a 12:84 and a 36:84 gearset.

[InFlight]

Two stage 10:1 gearbox with Vex gears is no issue....

With a 12 tooth CIM gear.
48 and 20 on a lay shaft. CIM drives the 48, 20 drives the 50 on the output shaft.

(48/12)(50/20)=10:1

Replacing the 48 gear with a 44, 42, 40, or 36 would reduce the gear ratio and provide faster velocity and lower torque.

[EricH]

Originally Posted by InFlight

Two stage 10:1 gearbox with Vex gears is no issue....

With a 12 tooth CIM gear.

Just as a point of clarity, VEX could commonly refer to any one of the following:
-VEX Robotics (division of IFI)
-VEX Robotics Competition (VRC) (robot competition using VEX EDR and IQ robots)
-VEX IQ (robot parts series designed for the same market as LEGO Mindstorms/FLL)
-VEX EDR (robot parts series designed for the same target age as FTC--the original FTC kit...)
-VEXPro (robot parts series designed for FRC)

From the context, you're referring to VEXPro, while the OP is referring to one of the other items on the list, likely VRC or VEX EDR (or both, given that VEX EDR is used in VRC). CIMs don't work very well with the EDR line.

[Karthik]

Originally Posted by EricH

-VEX Robotics Competition (VRC) (robot competition using VEX EDR and IQ robots)

Minor correction. The VEX Robotics Competition specifically refers to a robotics competition for middle and high school students using VEX EDR parts. The VEX IQ Challenge is a robotics competition for elementary and middle school students using VEX IQ parts.