toma@tekchips.UUCP (Tom Almy) (06/04/84)
I have found that using a spreadsheet program to be a really useful and interactive way to observe changes in gearing. The independent variables are the sizes of the gears, size of wheel, and cadence(!) and the dependent variables are gear inches and speed for each combination of gears and the percent change between chain wheels and rear cluster gears. The display looks like this: Wheel Size: 27 Cadence: 60 Inches Speed 34 47 52 34 47 52 14 xx xx xx xx xx xx 17 xx xx xx xx xx xx 20 xx xx xx xx xx xx 24 xx xx xx xx xx xx 28 xx xx xx xx xx xx 34 xx xx xx xx xx xx % Change 38 11 21 18 20 17 21 The %change chart is particularly useful to set up half-step shift patterns, the speed chart will tell you how fast you will travel at any particular cadence, and the standard gear chart will indicate shift patterns. To be fancy, the values in the upper left and lower right corners can be eliminated since they are not desirable gears. No source is included, that is left as an exercise for the cyclist.