[Fun   ] [Cycling          >] [Ratio Calc        ]

RatioCalc

31-Aug-2024 HTML forms Javascript Fixed gear set up

Welcome to RatioCalc! In 2024, I was getting ready for the London urban hill-climb competition. I wanted to compare sprockets without buying and trying each one - writing this app gave me the tools to do just that. I also got a deeper understanding of the mechanics involved in cycle transmission and some real-world experience working in JavaScript.

Although I designed it with fixed gear bikes in mind, it works just as well for all bikes (just takes a bit longer!)

Instructions for use

  1. Select the wheel & tire combo
  2. Select the chainring & sprocket combo
  3. Specify a target speed & distance
  4. Press calculate. The system will return outputs calculated for your setup.

Input parameters

Wheel/Tire: 20" x 1.75"
26" x 1.25"
700 x 25C
27" x 1 1/4"
       
teeth
teeth
km/h
km
       

Output results

Ratio:
0.00
 :1
Development:
0.00
 metres
@ 40 rpm:
0.00
 km/h
@ 60 rpm:
0.00
 km/h
@ 80 rpm:
0.00
 km/h
@ 100 rpm:
0.00
 km/h
@ 120 rpm:
0.00
 km/h
0.00
 RPM
0.00
 many times
       

If you are unfamiliar with the terms and concepts here, please refer to Sheldon "Coasting Is Bad For You" Brown page.