Credit: The code and the considerable work in curating the
cassette_key.csv dataset, in working out the logic underlying the
functions in bicycle_gears.R, and the examples for each function was
all done by David Roberts and described - along with commentary on why
one front chainring (1x) is better than two (2x) in in his April 6 2016
blog post from Cycling gear ratio calculator for R (or why you should
just go buy a SRAM Eagle 1×12 group right
now).
I was interested in exploring different combinations, so naturally the first thing I did was search Google for “R bicycle gear ratios” and came across his blog post. Then decided to post on GitHub to make it easier for others to use.
Things you can do to contribute: - Improve & extend figures - Develop a shiny app - Finish converting into an R package
- Functions are in
R/bicycle_gears.R. - Data is in
data/cassette_key.csv.
## Warning: package 'dplyr' was built under R version 4.0.3
## # A tibble: 79 x 47
## Manufact NSpeeds SmallCog LargeCog T9 T10 T11 T12 T13 T14 T15
## <chr> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
## 1 campagno~ 10 11 23 NA NA 11 12 13 14 15
## 2 campagno~ 10 11 25 NA NA 11 12 13 14 15
## 3 campagno~ 10 12 23 NA NA NA 12 13 14 15
## 4 campagno~ 10 12 25 NA NA NA 12 13 14 15
## 5 campagno~ 10 12 27 NA NA NA 12 13 14 15
## 6 campagno~ 10 12 30 NA NA NA 12 13 14 15
## 7 campagno~ 10 13 26 NA NA NA NA 13 14 15
## 8 campagno~ 10 13 29 NA NA NA NA 13 14 15
## 9 campagno~ 10 14 23 NA NA NA NA NA 14 15
## 10 campagno~ 11 11 23 NA NA 11 12 13 14 15
## # ... with 69 more rows, and 36 more variables: T16 <dbl>, T17 <dbl>,
## # T18 <dbl>, T19 <dbl>, T20 <dbl>, T21 <dbl>, T22 <dbl>, T23 <dbl>,
## # T24 <dbl>, T25 <dbl>, T26 <dbl>, T27 <dbl>, T28 <dbl>, T29 <dbl>,
## # T30 <dbl>, T31 <dbl>, T32 <dbl>, T33 <dbl>, T34 <dbl>, T35 <dbl>,
## # T36 <dbl>, T37 <dbl>, T38 <dbl>, T39 <dbl>, T40 <dbl>, T41 <lgl>,
## # T42 <dbl>, T43 <lgl>, T44 <dbl>, T45 <dbl>, T46 <dbl>, T47 <lgl>,
## # T48 <lgl>, T49 <lgl>, T50 <dbl>, T51 <dbl>
## [1] 10 12 14 16 18 21 24 28 32 36 42 50
## [1] 9 10 11 12 13 14 16 18 21 25 30 36 42
## [1] 2091
## [1] 2099
## [1] 12 13 14 15 16 17 19 21 23 25 28
## $`39T`
## # A tibble: 11 x 7
## chainring cog gearRatio gearInches develMetres KPH.50RPM KPH.100RPM
## <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
## 1 39 12 3.25 85.5 6.82 20.5 40.9
## 2 39 13 3 78.9 6.3 18.9 37.8
## 3 39 14 2.79 73.4 5.86 17.6 35.2
## 4 39 15 2.6 68.4 5.46 16.4 32.8
## 5 39 16 2.44 64.2 5.12 15.4 30.7
## 6 39 17 2.29 60.2 4.81 14.4 28.9
## 7 39 19 2.05 53.9 4.3 12.9 25.8
## 8 39 21 1.86 48.9 3.9 11.7 23.4
## 9 39 23 1.7 44.7 3.57 10.7 21.4
## 10 39 25 1.56 41.0 3.27 9.81 19.6
## 11 39 28 1.39 36.6 2.92 8.76 17.5
##
## $`53T`
## # A tibble: 11 x 7
## chainring cog gearRatio gearInches develMetres KPH.50RPM KPH.100RPM
## <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
## 1 53 12 4.42 116. 9.28 27.8 55.7
## 2 53 13 4.08 107. 8.56 25.7 51.4
## 3 53 14 3.79 99.7 7.96 23.9 47.8
## 4 53 15 3.53 92.8 7.41 22.2 44.5
## 5 53 16 3.31 87.1 6.95 20.8 41.7
## 6 53 17 3.12 82.1 6.55 19.6 39.3
## 7 53 19 2.79 73.4 5.86 17.6 35.2
## 8 53 21 2.52 66.3 5.29 15.9 31.7
## 9 53 23 2.3 60.5 4.83 14.5 29.0
## 10 53 25 2.12 55.8 4.45 13.4 26.7
## 11 53 28 1.89 49.7 3.97 11.9 23.8
## [1] 12 13 14 15 16 17 19 21 23 25 28
## [1] 10 12 14 16 18 21 24 28 32 36 42 50
## Warning: package 'ggplot2' was built under R version 4.0.3
