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Unread 03-11-2015, 23:21
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asid61 asid61 is offline
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Re: Help with gear sizes

Quote:
Originally Posted by dmorewood View Post
Where did you get this picture from? If I had to take a guess the big gear on the drive shaft looks like an 84 tooth hex gear, assuming that those are 4" omni's. Also I'm pretty sure that there are 12 teeth on that pinion gear. I would suggest VexPro for gears, you can also buy the omni's there if you want.
And 84t gear would be larger than 4" omni wheels. That is a 72 tooth gear mating with a 12 tooth gear.
Gear diameter = (teeth + 2)/pitch. Vex gears are 20 pitch, so an 84t gear has a diameter of (84+2)/20 = 86/20 = 4.3" diameter. A 72t gear by comparison is 74/20 = 3.7" diameter.
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