Lab 001 · Live experiment
Fixed gear, made legible.
The original Surplace calculator contains a remarkable amount of cycling knowledge in a very small interface. This version keeps that directness, then makes the arithmetic easier to read, compare, and learn from.
The question
What changes when one tooth moves from the chainring to the sprocket—and how can a rider understand the result without decoding a spreadsheet?
001 / live.client
Fixed gear calculator
Change the setup. The analysis updates immediately.
48 × 172.82
output.json
Analysis
Ratio
2.82Rear-wheel turns for every complete turn of the cranks.Skid patches
17Distinct tire positions that touch the road while skidding.Rollout
5.94 mDistance travelled by one complete turn of the cranks.± 2%
Equivalent gears within 2%
Choose a combination to load it into the calculator.
50—130 rpm
Cadence / speed
Calculator results updated
01 / input
The approach
Keep every input visible, update the analysis immediately, and place a plain-language definition beside each number. The wheel diagram shows skid wear as part of the calculation, not decoration.
02 / output
The working answer
A small client-side calculator with no account, no saved state, and no hidden server work. Change a value and the ratio, rollout, equivalent gears, and cadence table recalculate in place.