What is a planetary gear?

http://www.neugartusa.com/Service/faq/Plratio.pdf Planetary Gear Ratios and Rating Ratio = (Ring gear Diameter / Sun Gear Diameter) +1 = = (Number of Ring Gear Teeth / No. of Sun-gear Teeth )...

Planetary gearing is also known as Epicyclic gearing. It is a gearing system consists of external and central gears. External gears are also known as planet gears while internal gear is referred as...

How about a compound planetary gearset?

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1st gear is the gear where you can pedal with the least resistance. For a bicycle with external gears the chain should be on a big sprocket at the back and a small chainwheel at the front.