Saddle height calculator

How the saddle height calculator works

Saddle height is the most important number in your bike position. Too low and you lose power and the front of the knee can get sore. Too high and your hips rock and the back of the knee or your lower back can complain. This calculator gives you a starting height from your inseam using two classic methods, then shows you how to fine-tune it. It is one of the free LeCoach cycling calculators.

• LeMond method: saddle height = inseam × 0.883, measured from the centre of the bottom bracket to the top of the saddle, along the seat tube.
• 109 % method (Hamley): saddle height = inseam × 1.09, measured from the pedal axle with the crank pointing down in line with the seat tube, to the top of the saddle.
• Knee-angle method (Holmes): with the pedal at the bottom of the stroke, your knee should bend 25 to 35 degrees.

The first two give a number for a tape measure; the third is the check on the bike.

Saddle height by inseam

The two methods agree closely once you allow for the crank. For the 84 cm inseam, 91.6 cm minus a 172.5 mm crank is 74.3 cm, within about 1.5 mm of the LeMond figure. If your two measurements disagree by more than that, recheck where you measured from.

How to measure and set it

1. Measure your inseam properly. Stand barefoot against a wall, press a hardback book up between your legs as firmly as a saddle, and measure from the floor to the top of the book. The same measurement drives the bike size calculator.
2. Find the centre of the bottom bracket. That is the centre of the axle the cranks turn on.
3. Measure along the seat tube to the top of the saddle, where your sit bones rest, not at the nose.
4. Set the height and mark the seatpost with tape so you can return to it.
5. Ride and check the knee angle. With the pedal at the bottom of the stroke, your knee should bend 25 to 35 degrees. Film yourself from the side and measure the angle from hip to knee to ankle.
6. Adjust 2 to 3 mm at a time, and ride a few times between changes.

Peveler and colleagues compared these methods in trained cyclists and found that the inseam formulas often put riders outside the 25 to 35 degree range, so they recommended using the knee angle for the final setting. Treat the formulas as a starting point and the knee angle as the check.

Common mistakes

• Measuring to the nose of the saddle. Measure to the point where you sit, along the line of the seat tube.
• Using trouser inseam. It is shorter than your real inseam, so your saddle ends up too low.
• Ignoring shoes and cleats. Thick soles and tall pedal and cleat stacks change your effective leg length. The knee-angle check accounts for them; a formula does not.
• Changing too much at once. A 1 cm jump can swap one problem for another. Move 2 to 3 mm and give it a few rides.

Signs your saddle height is wrong

• Too low: knees come up high, you feel cramped, and the front of the knee can ache. Power feels low.
• Too high: hips rock side to side, toes point down at the bottom of the stroke, the back of the knee or your hamstrings can ache, and you may get saddle sores.

If knee, hip or back pain does not settle within a few rides of a small change, or if you notice swelling, stop adjusting and see a physiotherapist or doctor. A professional bike fit is also worth it if you ride long distances.

When to recheck your saddle height

• New shoes, pedals or cleats.
• A new saddle, which may be thicker or thinner.
• A new bike or crank length. Shorter cranks need a slightly higher saddle, longer cranks a slightly lower one.
• After an injury or a long break.

Flexibility and strength help you hold any position comfortably. Our guides to mobility training for cyclists and core training for cyclists cover the basics, and cycling training for beginners helps if you are new to riding. A good position makes every watt count. LeCoach makes sure those watts go into the right training.