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Old September 23rd 17, 05:37 AM posted to rec.bicycles.tech
Emanuel Berg[_2_]
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Posts: 1,035
Default program to compute gears, with table

Andre Jute wrote:

Why are you making it so complicated?
At
http://coolmainpress.com/BICYCLINGHebieChainglider.html
you can see how simple I made it in Excel.


BTW, what formula did you use?

I made one change, shouldn't the tire be
counted twice when one computes the diameter?

Do you get the same data for the same
configuration, which is:

chainrings 34 50T
sprockets 12 13 15 17 19 21 23 25T
bsd 622 mm
tire 23 mm

Better compare notes carefully after all...

BSD: 622 mm
ti 23 mm
wheel: 622 + 2*23 = 668 mm
roll-out = chainring/sprocket * wheel

chainring sprocket roll-out

34 25 2854.1
34 23 3102.3
34 21 3397.7
34 19 3755.4
50 25 4197.2
34 17 4197.2
50 23 4562.1
34 15 4756.8
50 21 4996.6
34 13 5488.6
50 19 5522.6
34 12 5946.0
50 17 6172.3
50 15 6995.3
50 13 8071.5
50 12 8744.1

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