Measuring your inside leg (or inseam) is a crucial step in determining the correct bike frame size. Here’s a breakdown of how to do it accurately:

What You’ll Need:

  • A measuring tape
  • A flat, hardcover book (or similar flat object)
  • A wall

STEPS

1. Stand Against a Wall:

  • Stand with your back against a wall, with your feet shoulder-width apart and flat on the floor.
  • Make sure you’re not wearing shoes.

2. Position the Book:

  • Place the hardcover book vertically between your legs, with its spine against the wall.
  • Slide the book upward until it’s snug against your crotch, mimicking the pressure of a bicycle saddle.

3. Measure:

  • While holding the book firmly against the wall, have someone measure the distance from the top of the book’s spine to the floor.
  • If you’re alone, carefully mark the wall where the top of the book is, and then measure from the floor to that mark.

4. Repeat:

  • It’s a good idea to repeat the measurement a couple of times to ensure accuracy.

Why This Measurement Matters:

Standover Height:
  • The inside leg measurement helps determine the bike’s standover height, which is the distance between the top tube of the frame and the ground.
  • You should have sufficient clearance (at least an inch or two) between the top tube and your crotch when straddling the bike. This prevents injury.
Frame Size Guidance:
  • Bike manufacturers use inside leg measurements, along with your overall height, to provide frame size recommendations.

Important Considerations:

Bike Type:
  • The ideal frame size can vary depending on the type of bike (road bike, mountain bike, hybrid, etc.). Each type has different geometry and riding positions
Manufacturer’s Sizing Charts:
  • Always refer to the specific manufacturer’s sizing charts, as they can differ.
Professional Fitting:
  • For the most accurate fit, consider a professional bike fitting.

It’s important to understand that bike sizing can vary significantly between manufacturers. Therefore, the following tables are intended as general guidelines. Always consult the specific sizing chart provided by the bike manufacturer you are considering.

Key Considerations:

Here’s a breakdown of general sizing guidelines, considering inside leg measurements and corresponding frame sizes for different bike types:

Measurements:

  • Inside leg measurements are crucial, but overall height also plays a significant role.
  • Frame sizes can be expressed in centimetres (cm) or inches (in).

Variations:

  • Women’s specific bikes often have different geometry and sizing.
  • Mountain bike sizing is often based on frame size (in inches), while road bike sizing is often based on frame size (in centimetres).
  • Hybrid and city bikes can vary, and often use Small, Medium, Large type sizing.

General Bike Sizing Guidelines:

General Bike Sizing Guidelines:

Road Bikes
Inside Leg (cm) Suggested Frame Size (cm)
71 – 76 51 – 53
76 – 81 54 – 56
81 – 86 56 – 58
86 – 91 58 – 60
Mountain Bikes (Hardtail)
Inside Leg (inches) Suggested Frame Size (inches)
28 – 30 16 – 17
30 – 32 18 – 19
32 – 34 20 – 21

 

Hybrid/City Bikes

Hybrid and city bikes often use S, M, L sizing. Here is a general guide using inside leg measurements.

Inside Leg (cm) Suggested Frame Size
71-76 Small/Medium
76-81 Medium/Large
81-86 Large/X-Large

 

Important Notes:

  • These are general guidelines, and individual preferences may vary.
  • Always prioritize a comfortable fit.

If you’re unsure, it’s highly recommended to visit our local bike shop for professional fitting advice.