Saddle height is the single most important bike fitting adjustment. The calculator below gives your starting value using the LeMond method. The definitive validation comes from measuring your knee angle at bottom dead centre (140°-150°). A few millimetres of error is enough to cause chronic knee pain.
The accuracy of your inseam measurement determines the accuracy of the calculation. A 10 mm error in inseam translates to ~8 mm error in saddle height.
Stand barefoot, back straight against a wall. Feet slightly apart at hip width. Heels against the wall.
Slide a rigid book between your legs horizontally and press it firmly against the perineum, as if sitting on a saddle. The book must be perfectly level.
Measure from the floor to the top edge of the book. Repeat twice and average. This value in millimetres goes into the calculator above.
The LeMond formula is a starting point. Joint angles measured while pedalling are the clinical validation. These are the ranges used by professional bike fitters and referenced in the biomechanics literature (Bini et al., 2011; Holmes et al., 1994).
Most cyclist pain has a biomechanical origin directly linked to saddle height. Identifying the pain often leads to diagnosing the setup error.
Clinical note: These diagnoses are indicative. Saddle height is often the primary cause, but other parameters interact: saddle setback, cleats (Q-Factor, rotation), crank length and individual morphology (femur length, hip mobility). A complete assessment including video analysis remains the only reliable approach.
Calculate your theoretical height using the calculator above. This is your starting point. First set your saddle to this value, measuring precisely from the bottom bracket axle to the top of the saddle along the seat tube axis.
Initial adjustments are made on a trainer for controlled conditions. Pedal for 10 to 15 minutes to warm up, then film yourself from the side. Watch the pelvis: if it rocks, the saddle is too high. If your legs feel crushed, too low.
Never change the height by more than 3 mm at a time. The body needs time to adapt. Between each adjustment, ride at least one or two sessions before modifying again. A sudden 10 mm change is a source of injury.
The final clinical validation is based on measuring the knee angle in extension at bottom dead centre (6 o'clock). The target is 140° - 150°. This is exactly what FramIQ measures by real-time video analysis on iPhone, without professional equipment.
The LeMond formula gives the starting point. FramIQ measures your actual joint angles while pedalling (knee, hip, torso) for a precise adjustment to the nearest degree. Cleat module is free and unlimited.