Crank Length Calculator

How to Measure Inseam Length?

To measure your inseam length accurately, follow these five straightforward steps:

1. Gather your materials: You'll need a book that's approximately 0.75 to 1 inch (1.9-2.5 cm) thick and a measuring tape or ruler.
2. Remove your shoes: Take off your footwear and stand with your back flat against a wall, ensuring your feet are flat on the floor.
3. Position the book: Place the book between your legs, pulling it up firmly against your crotch area. Hold it in place with your thighs, making sure one side of the book is pressed flat against the wall.
4. Take the measurement: Using your tape measure, measure the distance from the top edge of the book down to the floor. Keep the tape measure straight and perpendicular to the floor for an accurate reading.
5. Record your measurement: Note down the measurement you've taken. This is your inseam length, which you can use in the calculator above.

Frequently Asked Questions

What are the most common crank lengths?

The most common lengths are 165, 167.5, 170, 172.5, and 175 mm. But some manufacturers produce even shorter or longer cranks.

What is the ideal crank length?

The ideal crank length is not a one-size-fits-all measurement; it varies from one cyclist to another. Several factors come into play when determining the optimal crank length, including the cyclist's height, leg length, riding style, and personal preference.

For cyclists with longer legs, longer cranks might provide a more comfortable pedaling motion, allowing for a better extension of the legs during each stroke. On the other hand, cyclists with shorter legs might find shorter cranks beneficial, as they can reduce strain on the knees and enable a higher cadence.

Additionally, your riding style also matters. For instance, mountain bikers often prefer shorter cranks to improve ground clearance and navigate challenging terrains more effectively. In contrast, road cyclists might prioritize longer cranks to maximize power output during long rides on smooth roads.

Are shorter cranks better?

Shorter cranks can benefit some cyclists, reducing knee strain, enabling a higher cadence, improving ground clearance, and enhancing comfort for those with limited hip flexibility. However, the ideal crank length varies based on individual factors. I recommend consulting a bike fitter to determine the right crank length for your specific needs.

Does crank length affect saddle height?

Yes. The length of the cranks affects the saddle height. Shorter cranks lead to a higher saddle position. This is usually more aerodynamic than a lower saddle and longer cranks. This is because shorter cranks and a higher saddle position result in a more drop, which leads to a lower head and torso position. But it depends on each individual case.