by Steve McCulley
This is probably the most common question we get asked!
Of all the ways your body makes contact with your bike, saddle height is the most important. Get it right and you’ll be able to cycle without worrying about your position on the bike, as well as reduce the chance of gaining an injuring inherent with a repetitive pedalling motion. Get it wrong and you will undoubtedly increase the risk of injury, let alone be uncomfortable.
There are many formulae for working out the appropriate height for your saddle, as well as a few old wives’ tales, nonetheless it is the most common question we get asked. The best option would be to have a bike fit conducted by a certified fitter, however, we understand that is not an option for everyone. I therefore thought it would be useful to produce a short post on the topic.
While there is agreement on a general saddle height ‘window’, there is no consensus on the ideal for any given person. To illustrate this I’ll outline four of the most popular methods and highlight the differing results from them. I’ll consequently recommend which one I believe to be the most useful and accurate.
How to Measure Your Leg Length
This is an important part because your crotch-to-floor distance is a key measurement in determining saddle height. So, to get that measurement:
Inseam Measurement
- Stand barefoot with your legs and back against a wall; your feet should be approximately 20cm apart.
- If you have a carpenter’s square, place it between your legs. If you don’t have a square, you can use a large (thin’ish) book…you need something with a right angle.
- Snug the square/book into your crotch with a similar pressure to what you’d feel on a saddle. One edge of the square/book should be flush against the wall and the other sticking out in front of you as if you were sitting on it.
- You will then need a willing assistant to measure from the top edge of the square/book to the floor (in cm). This figure is your crotch-to-floor measurement.
To illustrate the four methods I’ll use my crotch-to-floor measurement of 88cm.
Heel-on-Pedal Method
Heel on Pedal
Sit on your stationary bike with both feet on the pedals – you will need to be next to a wall to balance, or ask someone to hold the bike with you on it. Pedal backwards a few rotations so that you settle on the saddle in your normal position. Now place your heels on the pedals and slowly pedal backwards. Your heels should just keep contact with the pedals at the bottom of the rotation, as your leg straightens, with no hip-rocking necessary.
Shoe sole and pedal thickness will affect this method, thus changing the saddle height dependent on those factors. When I measure the distance between the centre of the chainset, along the seat tube to the top of the saddle, I get a measurement of 76.2cm.
109% Formula
First of all, multiply your crotch-to-floor measurement by 1.09. This gives me a figure of 95.9cm. You then set the saddle using this figure by measuring from the top of the saddle to the top of the pedal, when the crank arm is straight down in the 6 o’clock position.
With the saddle in this position, when measured from the centre of the chainset along the seat tube to the top of the saddle, I get a measurement of 78.6cm.
LeMond Method
Greg LeMond, the famous American professional cyclist of the 1980s, gave his name to this formula and it involves multiplying your crotch-to-floor measurement by 0.883. This figure was determined by LeMond’s French coach, Cyrille Guimard, in the early 80s.
Back then cyclists wore leather-soled shoes with toe clips and straps. With the advent of clipless pedals and composite shoes soles (making them thinner), 5mm should be subtracted from the figure. This gives me 77.2cm. Again, this measurement is used between the centre of the chainset and the top of the saddle.
Pruitt Method
Goniometer
Renowned bike fit expert, Dr Andy Pruitt, started using a Goniometer (large protractor-like instrument) to check leg extension by measuring the angle of the knee when the pedal is at dead-bottom-centre (6 o’clock position). He believed the saddle would be at the optimum height when the knee flexion is between 25-30º.
At a 28º knee angle when my pedal is dead-bottom-centre, the saddle height is 77.0cm.
Conclusion
We first need an accurate baseline saddle height from which to compare the four methods. To get an accurate measurement I used our Retül 3D motion analysis equipment (where we use a 35-40º knee angle for a road bike fit), which puts my saddle height at 75.0cm. Although this figure is less than all four methods, it does not necessarily indicate that they are wrong.
The methods I have outlined were all devised some time ago and since then a number of variables have changed as equipment has evolved. Pedals are generally not as deep as they used to be, so the feet are closer to the pedal axle, thus requiring a lower saddle position. Furthermore, as already mentioned, shoe soles have become thinner. It is also now recognised that pedal axles should sit in a line between the first and fifth metatarsals of the foot, hence cleats have move rearwards, producing the effect of shortening the leg/foot combination.
What should we make of this? You should definitely make an effort to adjust your saddle height to ensure you’re in a comfortable riding position. Yet, as I have highlighted, there is a range from which to work within.
Recommendation
Andy Pruitt’s method is clearly of not much use for most people, as a Goniometer is an instrument used by bike fitters, physios, occupational therapists etc. The 109% Formula would likely put your saddle a little too high, so we are therefore left with the Heel-on-Pedal and LeMond methods, both of which I would advocate as a good start point from which to find your optimum position.
Alternatively, get in touch and see if we can help.
