View Full Version : gear ratios

Screwloose

07-13-2000, 12:58 AM

I am trying to remember the ratios for reducing teeth on the pinion and spur gears . For instance say I have 32 pitch gears , a 30 tooth pinion and a 60 tooth spur . How would you figure out how to reduce the gear sizes ( teeth ) to keep the same ratio but but with less rotating mass ?

Grant Tokumi

07-13-2000, 03:59 PM

I think a good way to figure this out is to do cross product if you remember that in math class .

Using your values of a 30 tooth pinion and a 60 tooth spur , if you want the same ratio but usng a 14 tooth pinion , put it into the following cross product equation

30 14

-- = --

60 n

then cross multiply .

30 * n = 60 x 14

30 * n = 840

n = 840 / 30

n = 28

If you use a 14 tooth pinion , you ' ll use a 28 tooth spur to get the exact same ratio .

Who says you never use what you learn in school . This hobby has ALOT to do with math and physics . Keep those grades up , it may help you win a race =).

For you high school physic students , do you know why cars spin out ? It has to do with static and kinetic friction coefficients . A tire that stays on the ground ( static friction ) has more traction than that same tire that is spinning out ( kinetic friction ).

------------------

Grant Tokumi

R/C Archive

http://www.rcarchive.com

Paradigm

07-13-2000, 05:30 PM

And that is why anti - lock brakes and traction control work ... they ( try to ) keep the tires from locking up and spinning out ( respectively ) http://www.rccaraction.com/ubb/smile.gif

- David R .

Powered by vBulletin® Version 4.2.2 Copyright © 2019 vBulletin Solutions, Inc. All rights reserved.