Saddle height sets how far your knee bends at the bottom of every pedal stroke, and research reviews treat a knee-angle check as the most reliable way to set it. The catch most guides miss: the target number depends on how you measure. A knee angle read while you sit still is about 8 degrees smaller than the same knee read on video while you pedal, so you need the right range for your method. From a side-on video the app reads your knee angle at the bottom of the stroke and how steady your hips are. For knee pain that doesn't settle, see a professional bike fitter or a clinician.
Set up and starting point
Put the bike on an indoor trainer, level, and ride in your normal cycling shoes. Set the phone side-on, square to the bike, at about crank height, with the whole bike and rider in frame. Film at 60 fps if your phone offers it.
the camera sees the hip, knee and ankle of the near leg the whole time.
Use a quick starting point, then check it. The heel method (heel on the pedal at the bottom, leg just straight) or an inseam formula (109% of inseam measured to the pedal, or LeMond's 0.883 times inseam) gets you close. In one study the heel method landed in the target knee range about 70% of the time; in others, 109% of inseam missed it 63 to 73% of the time. Common methods were built mostly on men: in one indoor-cycling study they put only 20 to 33% of women in the target range.
this is a first guess, not the answer.
Check the knee angle
Pick the target range that matches how you measure. Sitting still with the pedal at the bottom (static, goniometer): 25 to 35 degrees of knee bend. On video while pedalling, at the bottom of the stroke: about 33 to 43 degrees. On video while pedalling, at your straightest point in the stroke: 30 to 40 degrees. Knee bend here means 0 is a fully straight leg; the angle inside the knee is 180 minus that number.
a clear but small bend at the bottom, never a locked knee.
Spin easy for about 3 minutes at a steady cadence near 80 rpm, then film the last minute. Read the knee angle at the bottom of 15 or so strokes and use the average, not one frame.
relaxed, steady pedalling, the way you actually ride.
Adjust in small steps
Move the saddle in small steps and re-film after each. In one study, going from 2% below to 2% above a rider's usual height straightened the knee by about 7 degrees, so a few millimetres matters. Raise the saddle if your bottom-of-stroke angle is above the range; lower it if it is below.
one change at a time, then check again.
Don't chase single degrees. A 2022 systematic review found changes under 4% of leg length made only trivial to small differences in knee loads and no difference in oxygen use. Get into the range, then ride on it for a few sessions before changing again.
settled, not fiddling every ride.
Feel it
Smooth pedalling with a small, comfortable bend at the bottom and no stretch to reach the pedal. Your hips stay mostly quiet on the saddle; some side-to-side movement is normal, but if your hips dip to each side to reach the bottom, you are reaching. A cramped, folded feeling at the top of the stroke points to a saddle on the low side. Within the 25 to 35 degree static range, riders in Peveler's trials used slightly less oxygen at the 25 degree end. Evidence that saddle height alone causes or prevents injury is still limited, so treat the range as a sensible target, not a guarantee.
Fix-its
- You checked a pedalling video against the 25 to 35 degree range That range is for a static check. Pedalling adds about 8 degrees at the bottom, so using it on video pushes the saddle too high. Use about 33 to 43 degrees for video at the bottom of the stroke.
- You set the height from an inseam formula and stopped there Formulas often land outside the target knee range. Use the formula as a starting point, then film and check the knee angle.
- Your knee bend at the bottom is well above the range (saddle low) Raise the saddle in small steps. Research suggests compression behind the kneecap rises as saddle height drops.
- Your knee is nearly straight at the bottom, or your hips dip side to side to reach Lower the saddle in small steps and re-film until the bottom-of-stroke angle sits in the range for your method.
- Knee pain that doesn't settle Stop adjusting by yourself and see a professional bike fitter or a clinician. Cleats, fore-aft position and training load also matter, not only saddle height.
Drill
- Baseline: 3 minutes of easy spinning near 80 rpm on the trainer, filming the last minute side-on. Average the bottom-of-stroke knee angle over about 15 strokes and write it down with your saddle height.
- Static cross-check: stop with the pedal at the bottom, sit normally, and have someone film or measure the knee. In adults it typically reads about 7 to 8 degrees less bend than your pedalling number.
- One-step adjust: change the saddle by a small amount, ride 3 minutes, re-film and re-average. Repeat until you are in the range for your method.
- Ride check: do your next few normal rides at the new height before changing anything else, noting knee comfort after each.
Sources
- Bini, Hume & Croft — Effects of bicycle saddle height on knee injury risk and cycling performance, Sports Medicine (2011)
- Bini & Priego-Quesada — Methods to determine saddle height in cycling: a systematic review, Journal of Sports Sciences (2022)
- Millour, Duc, Puel & Bertucci — Comparison of static and dynamic methods based on knee kinematics to determine optimal saddle height, Acta of Bioengineering and Biomechanics (2019)
- Ferrer-Roca, Roig, Galilea & García-López — Influence of saddle height on lower limb kinematics: static vs. dynamic evaluation, JSCR (2012)
- Ferrer-Roca et al. — Acute effects of small changes in bicycle saddle height on gross efficiency and lower limb kinematics, JSCR (2014)
- Peveler — Effects of saddle height on economy in cycling, JSCR (2008)
- Peveler & Green — Effects of saddle height on economy and anaerobic power in well-trained cyclists, JSCR (2011)
- Peveler, Pounders & Bishop — Effects of saddle height on anaerobic power production in cycling, JSCR (2007)
- Peveler et al. — Comparing methods for setting saddle height in trained cyclists, JEPonline (2005)
- Encarnación-Martínez, Ferrer-Roca & García-López — Influence of sex on current methods of adjusting saddle height in indoor cycling, JSCR (2021)
Last checked 2026-10-26.