How do I measure my inseam for crank length?

Stand barefoot against a wall. Place a book between your legs with the spine pressed up firmly (simulating a saddle). Measure from the floor to the top of the book spine. This is your cycling inseam.

What crank length should I use?

Crank length is typically calculated as a percentage of your inseam (usually around 18.5-21%). For most cyclists, this results in 165-175mm cranks. Shorter riders benefit from shorter cranks (165-170mm), while taller riders may use 175mm or longer.

Does crank length affect bike fit?

Yes, crank length affects your effective saddle height and hip angle at the top of the pedal stroke. Longer cranks require a lower saddle to maintain the same knee extension, and can cause hip impingement. Shorter cranks allow a higher saddle and more open hip angle.

What are the benefits of shorter cranks?

Shorter cranks offer several benefits: more open hip angle (better for flexibility-limited cyclists), higher achievable cadence, reduced knee stress at the top of the stroke, and better aerodynamics in a triathlon position. Many cyclists are switching to 165-170mm cranks.

Crank Length Calculator

Use this crank length calculator as part of a complete bike fit. Crank length changes knee extension, hip angle at the top of the pedal stroke, saddle height, and how comfortable you can stay in an aero or road position.

Why Use This Tool?

Improve Efficiency: Getting the right crank length can enhance your pedaling efficiency, making your ride smoother.
Boost Comfort: A properly sized crank helps reduce strain and discomfort, which is key for long rides.
Quick & Easy: It’s a fast, hassle-free way to receive personalized bike fit advice, ensuring your bike works best for you.

How to Use the Crank Length Calculator:

Enter Your Inseam: Input your inseam measurement (in centimeters) in the provided field.
Click Calculate: Hit the Calculate button to generate your recommended crank length.
Review Your Result: The tool will display your ideal crank length (in millimeters) based on your measurement.