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Friday, May 21, 2010

Lemond's Sizing Chart and Hamley's Method Charted

I've been thinking about what I have learned over the years concerning cycling and what might or could be important to newer riders and really all riders.  The knowledge of how to correctly determine the size of your road bike frame and your saddle height is definitely something that should be shared. Even seasoned vets should recheck their saddle position occasionally.

Lemond Sizing Method:
It is my opinion that the definitive sizing chart for frame size and saddle height can be found in Greg Lemond's Complete Book of Bicycling.  Keep in mind that Greg did not invent or actually determine this chart.  It was the product of research from Dr. Ginet, and supervised by Cyrille Guimard, who determined the ideal leg extension for maximum efficiency and power output while cycling, and made famous by the legendary cyclist, and 3 time Tour de France rider, Greg Lemond.   Basically the ideal optimal saddle height is approximately 96% of full leg extension.  The chart numbers come from a calculation of the inseam multiplied by .883 and then measured along the the angle of the seat tube from the center of the bottom bracket to the top of the saddle and take into consideration average shoe and cleat thicknesses.   The chart removes the burden of math. 

There are multiple ways to determine your ideal saddle height.  Here I will discuss the "Hamley Method"  as well as the Lemond Method, and supply charts for easy calculations.  It is my opinion that the Lemond chart should be the gold standard for determining saddle height, based not only on science, but real world results.     I would also say frame size as well, but it should be noted that Lemond's chart assumes standard or classic frame design.  So that should be considered for sloping top tube designs, et. al. 

Below is the data from Greg Lemond's Sizing Chart that can be found in his book, "Greg Lemond's Complete Book of Bicycling".  I've compiled the data into one single chart so that you may copy, paste, print or share it.  Data can not be copyrighted so feel free to use it as you like. 

The Lemond Frame and Saddle Height Sizing Chart

This is an extremely easy chart to use.  The most import calculation to determine is your inseam.  This is best done in bare socks against a wall with a 2" hardcover book placed firmly between your legs as though it was the saddle. 
Simply mark the top of the book on the wall.  To be accurate, do this measurement 3 or so times and take an average.  If you have a large range of numbers, you need therapy or some kind of help.  Badda bing, badda bang, you now have your inseam.

Look at the chart to see what frame size you should be riding  and what height your saddle should be. Both measurements are taken from the center of the bottom bracket (middle of the crank or spindle or axle) to the center of the seat tube lug, and the top of the saddle (keeping your measuring stick even with the angle of the seat tube).  It is important to measure in line with the seat tube.  (it is noteworthy to know that by sliding forward on the saddle you effectively lower your saddle/reduce your leg extension and by sliding backwards the opposite.)

This saddle height chart is for typical or average crank lengths 172.5mm.  You can add or subtract accordingly,  based on different crank lengths.

Hamley Sizing Method:
Now let's review the "Hamley Method" for calculating the ideal saddle height.  Hamley with Thomas (1967) found that maximum power, albeit over a shorter period of time, was produced at a saddle height that measured 9% greater than the inseam when measuring the distance from the pedal in the down position to the top of the saddle when measuring along the angle of the seat tube.  These findings were again confirmed by Faria and Cavanagh (1978) who demonstrated that approximately one percent less power could be delivered for every percent that saddle height deviated from 109%.  However, Nordeen-Synder (1977) found that the most efficient (least amount of oxygen consumed) was at a measurement of 107%  on the inseam length.  And this matches almost precisely with the Lemond numbers.

Using myself as an example:  If I adjusted my saddle to the Hamley Sizing Chart from the Lemond Sizing Chart, I would have to adjust my saddle up approximately 1.3cm.  However, if I adjusted my saddle from the Lemond position to Nordeen-Synder's optimal 107% position, my saddle would only move about 1.5mm.  This small amount is effectively zero, or the same, because it would almost certainly be within the margin for error from measuring.

My suggestion is that if you are a roadracer or time trialist you should adjust your saddle height to the Lemond Chart.  If you are a track sprinter you should adjust you saddle height to the Hamley sizing chart. 



Do not be overly concerned if you already own a frame and it does not match this chart.  I would still  use this saddle height and your handlebars can be adjusted by stem size and spacers  as necessary for fit.  This chart puts you very close to where you should be.

Saddle position:
Generally the saddle should be flat and the UCI rule book requires that the nose of the saddle be at least 5 cm behind the vertical plane from the center of the bottom bracket.  Old school says a plumb blob should drop from your knee cap to the center of the pedal axle when the crank arms are horizontal.  Don't sweat these details.  I personally would just meet the 5cm UCI rule.  The stuff I've read is that slightly more power is produced from the forward position over further back.  I personally move around on the saddle from time to time for comfort reasons and to wake the sleeping turtle.  Additionally,  when time-trialing or "closing the gap" I ride the tip of my saddle.  I believe this is common.

Handlebars & Stem Length:
As for the handlebar position:  I think a book or at least a chapter can be written on this one.  I personally ride with wide handle bars which I believed helped with leverage for climbing and general comfort.  However, I now believe a smaller bar is slightly more desirable because it has less surface area and is thereby more aerodynamic.  Some bike racers prefer a narrow width handlebar for maneuverability during sprints.     It is going to be somewhat subjective, but generally the handlebar width should match your shoulder width.    I will say, concerning bike racing, try to get as aerodynamic as you can in your position.  It is a huge deal.  Wind Resistance has an exponential quality to it each mile per hour over 20 mph.  I highly recommend reading my post on "Aerodynamics and how to be faster with no additional effort" for further information.

I don't have a strong opinion on stem length other than it must be long enough that when your are standing and climbing a steep incline, your knees should not touch your bars.  Also for greater aerodynamics/performance the stem should position the rider's body so that it is in a aerodynamic position (that is:  back near flat in relation to the earth).  Disregarding racing and performance,  the bar may be placed (determined by the stem length and angle) solely on comfort. 

Additional resources:
For a slightly more thorough description to bicycle sizing , handle bar, top tube and stem length go to this link.

I was going to link to the Lemond sizing charts  that I had bookmarked earlier. Surprisingly they were gone.  Happily I had copies of Lemond's chart in my cycling files.  Feel free to copy my chart here for your records.      Also I recommend reading "Greg Lemond's Complete Book of Cycling".  It is available at many public libraries and you can buy it used at Amazon.com

I hope this is helpful.  Happy riding everyone!

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9 comments:

  1. Dave,
    I was aware of the Lemond sizing chart, but I had long since discounted it for various reasons (a combination of my own intuition and the Competitive Cyclist chart) until I injured the back of my knee last winter during a ride. After hurting my knee, I reevaluated my position and revisited the Lemond chart only to realize that my saddle was a full two inches too high! Needless to say, the Lemond heighth was a difficult transition, but after my body adjusted I was measurably stronger. I would strongly recommend that all cyclists that haven't recently measured their saddle review this chart and do so-you'll be glad that you did.
    Chad

    ReplyDelete
  2. Thanks for sharing Chad. 2 inches too high does indeed sound like the culprit for your injury.

    Coincidently, Lemond was nearly 2 inches too short before he was corrected. (also one leg was shorter than the other, and that was corrected with spacers).

    In his book he points out that one of his rivals, Sean Kelly was too low, and probably would have been faster if adjusted properly. He was also thankful that Kelly wasn't faster.

    ReplyDelete
  3. thanks for this. So if I read this correctly @ a 32" inseam there is a 16cm or 6 inch difference between the two methods? 72 cm vs 88 cm?

    that is HUGE - did I do the math right?

    ReplyDelete
    Replies
    1. Your math is basically correct. To be precise, it's 71.78cm for the Lemond method and 88.62cm for the Hamley method.

      Please note that these numbers are measured from 2 different points for determining the final saddle height adjustment. Both are measured along the slope of the seat tube to the top of the saddle. However, Lemond's measurement is from the center of the BOTTOM BRACKET (or crank axle) to the top of the saddle, whereas Hamley's measurement is from the top of the pedal (with the crank arm down and in line with the slope angle of the seat tube) to the top of the saddle.

      If you add 172.5mm (average crank length) to Lemond's calculation you get 89cm for a 32 inch inseam. Again, Hamley's method gives us 88.62 with the same 32 inch inseam, but it's measurement is from the TOP of the pedal (crank length is the measurement from the center of the pedal axle to the center of the crank axle or spindle)and NOT from the top of the pedal.

      Note: when comparing the numbers from Lemond to Hamley please consider the thickness of the pedal in your calculation. By doing so it gives more measurement to the Hamley's method and effectively makes it's final saddle height just slightly higher than the Lemond's method.

      Delete
  4. thanks for the clarification on the two methods - I missed that.

    I am now in the process of lowering from 75.5cm (lemond) to 71.78 (well maybe .79) - seems like a huge change. Do you notice that your thighs hit your trunk when in the drops?

    ReplyDelete
  5. Hi,
    Bike Fitting
    After a great search I feel this blog was quiet amazing with the real information on bike fitting. So, keep writting.
    Thank you!

    ReplyDelete
  6. Hello,
    Bicycle Fitting
    I really found great knowledge upon bicycle fitting with amazing information with the latest technological facts.So, keep writing.
    Thank you!

    ReplyDelete
  7. Should the inseam measurement be taken with my cycling shoes on or barefoot?

    ReplyDelete
  8. You should be barefoot and standing on a hard surface.

    ReplyDelete

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