June 30th 2015 by Sigurbjörn
Made a little Gear Ratio calculator that you can find at The Bikecalculator page
It requires 5 things to calculate things for you (all of which you can leave at default if you want)
- Tire Size, pick your ISO or common name tire size from the list, if your size is missing, drop me an email
- Lower desired cadence, this is the lower mark of your desired cadence, if you're a hobby cyclist this is probably 60 RPM or so, if you're quite fit it's probably closer to 70
- Higher desired cadence, this is the higher mark of your desired cadence, if you're a hobby cyclist this is probably 80 RPM or so, if you're quite fit it's probably closer to 90
- Front crankset teeth, list the number of teeth in your front crankset here, separated by a comma, if there is only one, just enter one value (and no comma)
- Rear cassette teeth, list the number of teeth in all your rear sprockets here, separated by a comma, if there is only one, just enter one value (and no comma)
It will then calculate the following information
- Gear inches for every front/rear combination of gears, a gear inch is the diameter (in inches) of the drive wheel of a Penny-farthing bicycle with the same gearing. These values range from low (20ish) to high (120ish), where low means it's slower (and easier to peddle) and high means it's faster (and harder to peddle)
- Metres of development, how many meters the bike will progress given one turn of the crank
- Cadence required to reach Kilometers/hour, the number of times you have to spin the crank per minute to reach the desired speed in Kilometers an hour for each gear available
- The page will take your desired cadence values and calculate a medium cadence value which is between your lower and higher value (if your lower is 60 and your higher is 80, then this medium value is 70)
- It will also calculate the difference between your lower and higher value and divide it by two to find the medium cadence range (if your lower is 60 and your higher is 80, then this medium cadence range is 10).
- It will then calculate a lowest cadence by deducting half your cadence range from your lower value (lower is 60, higher is 80, lowest is then 50)
- And additionally a highest cadence by adding half your cadence range to the higher value (lower is 60, higher is 80, highest is then 90).
- Cadence values that fall between the lowest and your lower cadence value will be coloured blue
- Cadence values that fall between your lower cadence value and the medium cadence value will be coloured green
- Cadence values that fall between the medium cadence value and your higher cadence value will be coloured yellow
- Cadence values that fall between your higher cadence values and the highest cadence value will be coloured red
- Kilometers/hour at Cadence, this is how many Kilometers an hour you can reach at a given cadence for each gear available. Color coding is the same as in the Cadence to reach Kilometers/hour table
- Various figures shows your lowest possible gear (and ratio) and the lowest speed, as well as your highest possible gear (and ratio) and the highest speed. Speeds are based on your lower and higher cadence values. It will also tell you how many unique gear ratios are found within the gears on your bike
Suggestions for improvement in email please, and enjoy.