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Sturmey-Archer SW[1]
  Number of gear teeth        
Gear Sun Gear 1 Pinion to Sun 1 Pinion to Ring 1 Ring gear 1 Path, 1=R to P, 2=Direct, 3=P to R Gear Drive Ratio Drive ratio as fraction Ratio incre- ment
1 20 15 15 52 1 0.722   13/18  
2 20 15 15 52 2 1.000 1        1.385
3 20 15 15 52 3 1.385 1   5/13 1.385

[1]
John Allen:
Tooth counts verified:
http://my.ohio.voyager.net/~bdhayes/sa/sw.htm
https://hadland.files.wordpress.com/2012/07/1theory.pdf
https://hadland.files.wordpress.com/2012/07/2tables.pdf