# If I’m using a NEO with a 12t gear on it, and 6” wheels. What would my ratio be on the low end and the high end? What is my Feet Per Second?

We’re missing a large part of the equation here: what is the 12-tooth gear driving? Because it could honestly be driving any sort of gear. If the 12T gear is driving another 12T gear, your speed is 5880 revolutions/minute * 1 minute/60 seconds * 12 tooth driving/12 tooth driven * (6*pi) inches/1 revolution * 1 foot/12 inches = 153.86 feet per second. Of course, you’ll need an airport runway to reach that.

Similarly, if you found a 1000-tooth gear it would be 5880 revolutions/minute * 1 minute/60 seconds * 12 tooth driving/1000 tooth driven * (6*pi) inches/1 revolution * 1 foot/12 inches = 1.85 feet per second while doing a massive burnout.

You can probably calculate the answer based on that formula, but we’re happy to help if you’ll define the whole problem.

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Billfred nailed it. Not enough information.

NEO is a motor. You’re asking about a low end and high end ratio–that implies you have a shifting gearbox. what gearbox is not specified. You’ve stated a wheel size, but you want us to tell you a feet per second. Well… how fast is that wheel turning?

The general equation to find out the robot’s speed is: (motor free speed)/(gear reduction)(pidiameter), convert the length to feet, and somewhere along the line knock off some random percentage for efficiency losses (which depend on gearbox type, whether the mechanical crew got their holes straight or offset, and how much grease you put in, among other things). Because you apparently have a 2-speed gearbox, you’ll need to run that twice (once for high and once for low).

Time to redefine the problem.

1. What speed do you want your robot part to go?
2. How many speed options do you want?
3. Is there a specific gearbox you want to use?
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And dont forget the torque required as that will also limit RPM. Plus you got to make sure you don’t exceed the 40 A or whatever fuse you got and consider the capabilities of the motor driver etc etc

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