# V5 gear ratio

What gear ratio is needed to lift at least one or two VEXV5 balls from the 2020-21 challenge
I’m new to VEXV5 so if anyone could help out, that is appreciated

gear ratio is nowhere near enough information to figure this out

P = τ * ω
τ = sin(θ)*F
F = ma

it’s practically impossible to figure out what gear ratio will work most efficiently for something like this, especially without even telling us how much power (motors) you have allotted. there are way too many variables, and the ratio needed is best found through experience or trial and error anyways. besides, the ratio means nothing by itself. you need radius of the output, angular velocity (ω), and torque (τ). With that said, that makes power the variable that you really want, because as shown earlier, power is the product of angular velocity and torque. so how much power do you have? you can figure that out by telling us how many motors you’re using, and looking at the vex website to tell us that number in watts

if you really want to do this analytically (i dont recommend), we can go into further detail, but it’s a rabbit hole and will get your nowhere fast.

trial and error is your best friend

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This would depend on how long the arm you’re lifting with is, as well as how heavy the structure that holds the balls is. If you have exact numbers for these, then you can do some torque calculations and figure out how much torque you need to lift the balls.

Generally, I’d say you should be safe with a 1:3 or 1:5 ratio to lift 1-2 balls (this assumes you use the red 100 RPM cartridge)

(You can probably go faster than 1:3 100 RPM, but the setup I recommended would be almost guaranteed to have enough power)

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If you’re building a lift for the first time I would recommend using a 5:1 (1:5 if you read them that way, just gear it for torque) gear ratio. That is pretty standard and should have plenty of torque. Start using a red cartridge in the motor and if you can work up to it, try the green 200 rpm cartridge. Either of these combos should provide enough torque for your mechanism, but the latter would be faster, so if you can switch the motor after getting it to work that is naturally ideal. Regardless, be sure to use rubber bands to assist your lift as they are essential at providing extra strength to your lift

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You can definitely go faster than that . However I don’t recommend it for a first timer

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we need more information on what kind of robot you’re using. Are you building an arm to lift balls, or are you building a tray, or a conveyor system?

a good range of ratios for arms can be anywhere between 1:5 on a 200 rpm motor for really light lifts, and 1:7 100 rpm for really heavy lifts. (this game your lift should be pretty light, so somewhere around 1:7 on a 200 rpm motor should be a safe choice)

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I’m using the instructions from the VEX Crunchbot

In that case, the 5:1 gear ratio used in the Crunch instructions should work well.

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Can you list the motors from the least powerful to the most powerful and put the motor color beside it? thanks

it goes 100 rpm - red, 200 rpm - green, 600 rpm - blue.

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@Xenon27 's answer is correct, but to clarify a bit: all motors output the same amount of power. Each color cartridge has a different speed and torque. The 100 RPM (Red) motor has the highest torque but the lowest speed.

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Yes. Torque increases as speed decreases, and vice versa.

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