Reach And Stack Calculation

Reach and Stack Definition:

\[ \text{Reach} = \text{Horizontal Distance from BB to HT} \] \[ \text{Stack} = \text{Vertical Distance from BB to HT} \]

Bottom Bracket X Coordinate:

Bottom Bracket Y Coordinate:

Head Tube X Coordinate:

Head Tube Y Coordinate:

Reach:

Stack:

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1. What Are Reach and Stack?

Reach is the horizontal distance from the bottom bracket (BB) to the top of the head tube (HT). Stack is the vertical distance from the bottom bracket to the top of the head tube. These are key measurements in bicycle geometry that affect rider position and comfort.

2. How Are Reach and Stack Calculated?

The calculations are based on simple coordinate geometry:

\[ \text{Reach} = HT_x - BB_x \] \[ \text{Stack} = HT_y - BB_y \]

Where:

\( BB_x \) — X coordinate of bottom bracket
\( BB_y \) — Y coordinate of bottom bracket
\( HT_x \) — X coordinate of head tube top
\( HT_y \) — Y coordinate of head tube top

Explanation: These measurements are typically taken with the bike in a standard position, with the bottom bracket as the origin point (0,0).

3. Importance in Bike Fitting

Details: Reach and stack help determine how stretched out or upright a rider will be on the bike. They're crucial for comparing bike geometries and finding the right fit.

4. Using the Calculator

Tips: Enter the coordinates of your bottom bracket and head tube top in millimeters. The calculator will compute the horizontal (reach) and vertical (stack) distances between these points.

5. Frequently Asked Questions (FAQ)

Q1: Why are reach and stack important?
A: They provide a standardized way to compare bike geometries independent of other variables like seat tube angle or wheel size.

Q2: What are typical reach and stack values?
A: These vary by bike type - road bikes might have reach 380-420mm and stack 540-580mm, while MTBs are generally shorter in both.

Q3: How do I measure these coordinates?
A: Use a bike jig or wall-mounted measuring system with the bike perfectly level. Measure from BB center to HT top center.

Q4: Can I adjust reach and stack after purchase?
A: Yes, through stem length/angle, spacers, and handlebar choice, but frame measurements are fixed.

Q5: How does this relate to rider position?
A: Stack affects how high your hands are relative to BB; reach affects how stretched out you are. Both influence comfort and aerodynamics.