Examples
Examples
Try the starting example
- Front chainring tooth counts
- 40,20
- Rear sprocket tooth counts
- 10,20
- Unique wheel/crank ratios, low to high
- 1, 2, 4
- Adjacent ratio increases (%)
- 100, 100
- Largest adjacent ratio increase (%)
- 100
- Entered gear combinations
- 4
- Distinct exact ratios
- 3
Try another scenario
- Front chainring tooth counts
- 30,20
- Rear sprocket tooth counts
- 10,20
- Unique wheel/crank ratios, low to high
- 1, 1.5, 2, 3
- Adjacent ratio increases (%)
- 50, 33.3333333333, 50
- Largest adjacent ratio increase (%)
- 50
- Entered gear combinations
- 4
- Distinct exact ratios
- 4
Calculation method
Calculation method
Unique wheel/crank ratios, low to high
Compute front/rear for every pair; reduce each tooth pair by its integer GCD to recognise exact duplicates.
Adjacent ratio increases (%)
100×(next ratio/current ratio−1).
Largest adjacent ratio increase (%)
Maximum adjacent step, or zero for one unique ratio.
Entered gear combinations
Number of front counts×number of rear counts.
Distinct exact ratios
Count unique reduced tooth fractions.
Symbols and units
- a
- Front chainring tooth counts
- b
- Rear sprocket tooth counts
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Assumptions & limits
Assumptions & limits
- A ratio-spacing audit across all entered combinations. Equal exact fractions are merged; cross-chain restrictions, shifting compatibility, wheel size and cadence are not inferred.
Are these inputs private?
These calculations run in your browser. A shared link contains the values you choose to share. Only questions submitted to the separate AI finder are sent to OpenAI.
Further reading
OpenStax: arithmetic model background ↗
Background reading; this does not imply endorsement or independent review of SumFizz.