Quote:
Originally Posted by GeeTwo
The Vex Versaplanetary gearbox offers single stages ranging from 3:1 reduction down to 10:1 reduction.
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Side note: I think it's beautiful that the ratios offered are all clean integer ratios*, not messy repeating decimals. Planetary gear boxes of this variety have single stage ratios of Ring Gear Teeth/Sun Gear Teeth +1. The ring gears on Versaplanetaries are 72 teeth, which has factors 2x2x2x3x3. Using those factors in different combinations results in sun gears of 36, 24, 18, 12, 9, and 8 resulting in 3:1, 4:1, 5:1, 7:1, 9:1, and 10:1 respectively. 6:1 and 8:1 ratios would have required use of prime factors 5 and 7 respectively, which would increase the ring gear tooth count by that many, which is impractical.
*I understand by definition gear ratios are integer ratios, but when reduced to the mechanical advantage factor, only evenly divisible ratios give integer results.