By Rick Schultz
This question has come up several times while bike fitting clients. “Do you use the LeMond Formula to determine saddle height?”
RBR has covered the subject in the past here: Which Saddle Height Method Is Correct?
In that article, it’s correctly noted that the thickness of the pedals, the thickness of the soles of the shoes, as well as the thickness of the insoles, will affect this measurement. But there’s an even more important reason that almost everyone misses. The primary reason bike fitting experts don’t use this formula is because it doesn’t take crank arm length into account.
I use a goniometer (aka angle-finder) to determine saddle height based on knee angle at max extension.
The LeMond method takes the inseam * 0.883 = center of bottom bracket to top of saddle. But which crank size are you riding? If you ride shorter cranks, the saddle should be higher. And if you ride longer cranks, the saddle should be lower. So it’s much more accurate to find a correct saddle height by measuring a cyclist while they’re pedaling the bike on the trainer, which correctly sets the height for the actual bicycle that you are riding, with longer or shorter cranks.
Coach Rick Schultz is an avid cyclist who has trained, raced, and coached in Southern California and now resides in Bend, Oregon where he works as a bike fitter and bike fit educator. Rick is an engineer by trade and a prolific cycling product reviewer. He’s the author of Stretching & Core Strengthening for the Cyclist in the RBR eBookstore. Check his coaching site, www.bikefitnesscoaching.com. Click to read Rick’s full bio.
Not trying to be disrespectful, but the Lemond formula does take crank length in account. It is described on page 128 of Greg’s book, “Greg LeMond’s Complete Book of Bicycling” from way back in 1987.
Here it is defined – LeMond Method. Greg LeMond says to multiply your crotch-to-floor measurement by 0.883. This figure was determined in the early 1980s by LeMond’s French coach at that time, Cyrille Guimard. Back then, everyone was on cage pedals with toe clips and straps and wearing leather-sole shoes with nailed-on cleats. LeMond recommends subtracting 3 mm from the number produced by his formula if you use clipless pedals. Fred takes off another 2 mm because shoe soles have become thinner, too. Height is measured from the middle of the crank axle along the seat tube to the top of the saddle. Fred’s result is a saddle height of 77.2 cm.
So, where is the crank length mentioned in 0.883 x crotch to floor?
Karl’s correct, though Lemond didn’t change his saddle height with 175mm cranks, even though the formula is for 170mm cranks. I’ve been using it with 175mm cranks for decades and it’s worked well. That said, it doesn’t take complex math to add or subtract a few millimeters to compensate for crank length variances, if you feel you need to.
I’m also not convinced that a goniometer is any more precise, given that you’re working with bones and joints that are largely hidden by skin, muscle and fat. The exact pivot points are a best-guess and any error will affect the saddle height.
Somewhere I learned that seat height should be 1.15 times your inseam. I use it and works fine for me. Also some older riders knees do not bend as much so little higher is more comfortable.
This is virtually the same as the Lemond ratio.
Only “formula” I’ve found that works for me is the “Heel On Pedal” (with cycling shoes) method. Those other numerical formulas put my saddle 1-3 cm too high. (I know for a fact its too high at those heights, because a) my power drops so much that my speed is literally cut in half — or more — going up my local 12% grade, and, b) my hips bounce up and down so much, that I look like a freaking Mexican Jumping Bean on a Pogo Stick!)
As seen above, there are numerous methods that people refer to. My point is that the most famous is the Lemond method and that is the one I was referring to. Back in Lemonds day, they did not use 170, they used 175. So, we first need to know for certain what is the referenced crank length. So, lots of assumptions for a pretty precise formula with 3 significant digits. Another fallacy is to just add or subtract the same offset to the crank. Saddle moves up it moves back as well placing the rider higher than what is expected.
Static bike fit, dynamic bike fit, hybrid bike fit, they are all good if the fitter sticks to one method and uses that exclusively. There are plusses and minuses to each method, but a goniometer DOES take crank length into account where Lemond 0.883 x crotch length doesnt.
Hmm, I didn’t even know this formula was still being used, its ancient by todays standards.
I’ve always done best when I set my own saddle height. I don’t think a millimeter or two has much of an effect up or down anyway. Like I find it hard to believe when someone says they can notice 2psi difference in their tires. I use cranks that feel good when I ride and don’t fuss over length, if it works well and is tried and true I stick with it, and I’m in my 35th year of cycling and never had an injury or aggravated an injury due to poor fit.
Just have fun and ride, we only have one shot at life, so get the most out of it.
I’m surprised bike fit has been so slow to integrate power output into optimising rider positioning. Set them up using basic principles and test them for power and efficiency. Only amateurs like myself rely on goniometers and measuring tapes. Every rider will have a preferred position which will differ between individuals.. Some like to perch a little high even though their pelvic remains steady whilst others like to flex a lot through their knees and hips. The key is power output and not to forget comfort also.
I did 400+ Motion capture fits and always started with the Lemond method, just as a starting point. Then did heel method to verify there was no glaring error. Then I did the full MC fit.
The Lemond method is good to 1-1.5%, or basically a cm at 76cm. Fore/aft is a different story mostly due to the variation of lengths these days.
Anybody properly using Lemond and heel method is in a safe zone.
MC is still worth it if the fitter is good and the rider listens and does not mind spending the money.
Whether they were using 175mm or 170mm cranks is not as relevant as how one went about obtaining the inseam measurement to begin with.
As a former Fit Kit Level 1 bike fitter, we used the inseam tool, which was a spring loaded tool, and would provide measurements similar to holding a dowel or level at the crotch manually with approximately 30-50% of actual saddle pressure. Using myself as an example, that method would yield a number of 77cm. If I were to keep applying pressure to about the same amount of pressure experienced as if I were backpedaling on a bike, that measurement would jump up to 81cm. That’s a 4cm or greater than 1.5″ spread in measurement, much higher than the whole range of crank ranges offered by even today’s standards.
Bottom line, I asked people when we measured their inseam if they were comfortable with even that low amount of pressure exerted by the saddle and then went from there. Again, the LeMond method as well as the 109% method will get about 90% of the people 90% to their ideal position–most people are happy from there.