DIY gear ratio calculations with out a program (math, the dreaded math!)

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Dan

Staff
May 25, 2008
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Moosylvania
DIY gear ratio calculations with out a program (math, the dreaded math!)

I have always used calculator programs to work out gear ratios but always wanted to do the math my self.

Just now, figured out the equations. Not hard!

I will say how I did this particular equation but invite others to suggest easier or better methods and make fun of me.

The drive gear is 10 teeth (T) ((or inches. Does not matter as long as all things are measured in the same way. 10 teeth, inches MM, CM etc)

The drive gear is 10. The driven gear is 20.

20 '/. by 10 = 2

That gives you a 2:1 ratio.

Now we go to the secondary reduction. 9 driver to the rear wheel (driven) of 50.

50 '/. by 9 = 5.5

Multiply results by each other; 2 X 5.5 = 11 (just add ";1") and get 11:1 ratio.


Wut? worked on paper!
 
Last edited:

D.J.

Member
Jan 20, 2008
266
2
18
Canada
I picked up this book (14000 GEAR RATIOS) many years ago at a thrift shop. I bought the book because I couldn't believe that they would print a book like it. It was printed in 1942.