Crank Length Selector
The Crank Length Selector is a specialized bike-fit tool designed to help riders choose the ideal crank arm length for comfort, efficiency, and knee health.
Instead of guessing between 165mm, 170mm, or 175mm, the tool uses height, lower-body ratio, and riding style to provide a precise recommendation.
This tool is especially useful for cyclists who experience knee discomfort, riders who want better cadence performance, and anyone building or upgrading an e-bike or road bike.
Crank length affects:
Using an optimized crank length can significantly improve comfort and performance.
Input your exact height to calculate a baseline crank length.
This gives the tool a starting point based on average human proportions.
Select the option that best reflects your proportions:
This adjusts the calculation up or down by several millimeters to match your unique biomechanics.
Choose between:
Your discipline affects crank preference:
performance riders benefit from slightly shorter cranks, while touring riders may prefer more leverage.
The tool instantly calculates:
A dynamic graph (canvas chart) highlights your ideal position on the 150–180mm scale.
Use the recommendation to:
For most riders, switching even 5mm can make a noticeable difference.
The Crank Length Selector is:
It gives riders confidence when choosing crank arms — no more guesswork.
- Cadence: Shorter cranks allow smoother, higher cadence.
- Knee Stress: Longer cranks increase knee flexion and can cause discomfort.
- Power Delivery: The right length improves biomechanics and reduces wasted energy.
- Fit & Handling: Riders with shorter/longer legs benefit from tailored crank arms.
- Short legs compared to torso
- Average proportions
- Long legs compared to torso
- Casual / Fitness / Urban riding
- E-bike commuter
- Performance / Road / MTB
- High cadence / Low torque spinning
- Optimal crank length
- Acceptable range
- Biomechanics-based reasoning
- Choose the correct crankset size
- Upgrade from your current length
- Improve knee comfort
- Match your e-bike’s geometry
- Optimize spinning cadence
- Niche but highly valuable
- Perfect for enthusiasts, bike fitters, and e-bike hobbyists
- Simple to use yet biomechanically meaningful
- Better than generic size charts