Crank-to-Inseam Ratio

Calculate crank-to-inseam ratio from the supplied measurements.

Description

Crank-to-inseam percentage normalizes a crank dimension to a rider dimension.

Crank-to-inseam percentage normalizes a crank dimension to a rider dimension. The shared ratio uses lengths supplied in matching units.^[1]

Calculate crank-to-inseam ratio from the supplied measurements.

When to use Crank-to-Inseam Ratio

Use this tool to calculate crank-to-inseam ratio from the supplied measurements.

Prepare the measured movement, timing, load or preassigned score requested. Keep protocols, units, paired measurements and caller-selected thresholds consistent.

How to use Crank-to-Inseam Ratio and understand its results

Prepare the measured movement, timing, load or preassigned score requested. Keep protocols, units, paired measurements and caller-selected thresholds consistent.
Enter crankLengthMillimeters, inseamMillimeters using the field table and calculation rules, then run the tool.
Read crankToInseamPercent. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
crankLengthMillimeters	Crank length	number	Required
inseamMillimeters	Inseam	number	Required

Enter finite mm values with nonzero inseam. Return percentage; signed values are accepted.

percent=100crankLength/inseam

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
crankToInseamPercent	Crank-to-inseam ratio (%)	number

json

{
  "input": {
    "crankLengthMillimeters": 170,
    "inseamMillimeters": 800
  },
  "output": {
    "crankToInseamPercent": 21.25
  }
}

Limitations and assumptions

Physical lengths should be positive. No fit criterion, joint-angle analysis or crank recommendation is supplied.

Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Bike Saddle Inseam Fit: Estimate saddle height from inseam and a caller-selected fitting factor. For a complementary task, use Stack and Reach Fit Screen: Compare frame stack and reach with a caller-defined fit window.

References

Crank-to-Inseam Ratio — tool.io

Similar or alternative tools

Bike Saddle Inseam Fit
Estimate saddle height from inseam and a caller-selected fitting factor.
Stack and Reach Fit Screen
Compare frame stack and reach with a caller-defined fit window.