Bike Frame Geometry Calculator

Reach Formula:

\[ Reach = \frac{Stack}{\tan(Head\ Angle)} \]

Reach:

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1. What is Bike Frame Geometry?

Bike frame geometry refers to the measurements and angles that define a bicycle frame's shape and size. These measurements significantly impact the bike's handling, comfort, and performance characteristics.

2. How Does the Calculator Work?

The calculator uses the Reach formula:

\[ Reach = \frac{Stack}{\tan(Head\ Angle)} \]

Where:

\( Stack \) — Vertical distance from center of bottom bracket to top of head tube (mm)
\( Head\ Angle \) — Angle of the head tube relative to horizontal (degrees)

Explanation: Reach measures the horizontal distance from the bottom bracket to the top of the head tube, indicating how stretched out the bike's riding position will be.

3. Importance of Reach Calculation

Details: Proper reach measurement is crucial for bike fitting, ensuring comfortable riding position, optimal power transfer, and controlled handling. It helps determine the right frame size and stem length for individual riders.

4. Using the Calculator

Tips: Enter stack in millimeters, head angle in degrees. Both values must be positive, and head angle must be less than 90 degrees for valid calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical reach measurement for road bikes?
A: Reach varies by frame size and style, but typically ranges from 370-400mm for medium road bikes.

Q2: How does reach affect bike handling?
A: Longer reach creates a more stretched, aerodynamic position but may be less comfortable. Shorter reach offers a more upright, comfortable position but may feel cramped.

Q3: Can I adjust reach on my bike?
A: Yes, reach can be adjusted by changing stem length or angle, though extreme adjustments may affect handling characteristics.

Q4: How does reach differ from top tube length?
A: Reach is a more modern measurement that accounts for seat tube angle and provides a better indication of fit than traditional top tube length.

Q5: Should reach be the same for all bike types?
A: No, optimal reach varies by discipline - road bikes, mountain bikes, and gravel bikes have different ideal reach measurements based on their intended use.