FRC Blogged-Kit of Parts Drive System Option

[T^2]

Originally Posted by Ether

Also worth noting: in the real world, the % of "speed loss" is not constant when changing gear ratios either:

Team 1678 did some testing earlier this year on a bot with a 2-speed gearbox. The "Speed Loss Constant" was 92% in low gear and 72% in high gear.

Ether is correct on most accounts. Keep in mind that JVN's "speed loss constant" comes after a "drivetrain efficiency" (i.e. losses from gearing), therefore the 81% number cannot be attributed to gearbox losses. The testing we did earlier this year found the overall speed loss from the theoretical free speed of the motors. The numbers we found make intuitive sense, given that motor resistance, friction, rolling resistance, and air drag all tend to increase as speed increases.

My conclusion now is the same as it was then: test your drivetrain instead of blowing smoke from your behind about the theoretical speed you think you'll get.