Saddle height: how to calculate yours (LeMond formula + angle validation)

Saddle height is the single adjustment that changes your riding the most: it drives power, comfort and knee-injury risk. The good news is that it isn't guesswork — you can calculate a solid starting point with a tape measure and then refine it by watching your body in motion.

Step 1 — measure your inseam properly

Your inseam is the floor-to-crotch distance, barefoot. Stand with your back against a wall, place a book between your legs simulating saddle pressure, level the book and measure from its top edge to the floor. Don't use your trouser inseam: it's off by several centimetres.

Sanity check: the inseam usually lands near 47% of your height. Someone 175 cm tall tends to measure around 82 cm. If your number is far from that, measure again.

Step 2 — calculate the starting point

Greg LeMond's classic formula multiplies the inseam by 0.883 to get the distance from the centre of the bottom bracket to the top of the saddle, measured along the seat tube. With an 82 cm inseam: 82 × 0.883 ≈ 72.4 cm (724 mm).

That factor was calibrated with 170 mm cranks. If yours differ, compensate: longer cranks call for a proportionally lower saddle (your foot reaches further at the bottom of the stroke), and vice versa.

Step 3 — validate with your knee angle

Formulas are starting points; your body confirms. With the pedal at the bottom of the stroke (6 o'clock), the knee should hold 25–35° of flexion — the Holmes method window, the clinical reference for protecting the knee. That's exactly what FitRide measures through your camera, while you actually pedal.

• More than ~35° of flexion (knee too bent): saddle is low — raise it.
• Less than ~25° (leg nearly straight): saddle is high — drop it.
• Hips rocking on the saddle, or toes pointing down to reach the bottom of the stroke: classic signs of a high saddle.

How much to raise or lower?

Practical rule from our calculation engine: each degree of knee angle outside the window equals roughly 4 mm of saddle height. Adjust 5 mm at a time, ride a few minutes and re-check — big one-shot changes tend to trade one discomfort for another.