Originally Posted by 53-11_alltheway
This is where the online calculators are worthless. Besides the crank length modifies the ideal saddle height/position anyway.
What is probably more important is distance from BB center because that takes into account not only height (verical distance), but set-back (horizontal distance from BB)
Worthless? Disagree. Like all formulas, they put you in the game and they should be used directionally based upon where they came from. Lemond was an elite cyclist so of course his formula will not be directly applicable to lesser cyclists. Would say that for most good recreational if not amateur racers…those I know and respond on this board for example, the Lemond .883 x Cycling Inseam puts the seat up too high. I have known some racers where the formula works for them as well. Even among elite racers this formula is not the holly grail on either side. As to only measuring the vertical difference…not right either...not how the formula was meant to be used which is from BB to the highest point of the seat because what matters is the linear distance from your sit bone contact to the BB. This distance doesn't know or care how much set-back you are running or STA as they are irrelevant, i.e. a bike with small set-back and small STA = a bike with a big set-back and bigger STA...the net result being the rider ends up the same postion relative to the BB.
When you measure, the tape will end up unparallel to the seat tube if running more than 0 set-back which is true in my case for example because I run a fair amount of saddle set-back.
Originally Posted by Longfemur
I've known about those formulas for decades, but I've always had my saddle at least 2 cm lower. For one thing, these formulas are designed for the likes of Bernard Hinault and Greg LeMond - top notch road racers, not people like most of us. We don't put out enough power to have our saddles that high. Secondly, these formulas have no way of taking into account even just the thickness of the shoes we are wearing, let alone important factors like length of femur vs length of tibia, and foot length. Nor do they take into account where your saddle is in terms of fore-and-aft (or where the part of the saddle you actually sit on is in relation to the length of the saddle). Obviously, the farther back your sit bones are, the farther away you are actually going to be from the pedals. The formulas also don't know whether your foot is flat or pointed down at the bottom of the stroke. A pointed down foot adds a lot of length to your leg, doesn't it? So, in the end, as long as you don't have your saddle ridiculously low, like a child learning how to ride, you do what feels good for you. If you need some validation for this, you can take comfort in the fact that pro racers did not used to ride with their saddles as high as these formulas call for. For most people riding a road bike, a good saddle height would be anywhere between the high given by the x .883 formula, and the lower "limit" given by the heel on pedal method.
Believe this is well said and certainly mimics my experience as well. Patriot we are close to the same size…in height and weight. I have a 35.25” cycling inseam and my seat height per the Lemond method should be 31.125 and I run my seat up around 30.6-30.7” or so or almost ½” below the Lemond method. This is pretty common. I have resisted what I feel is correct and run it higher but I am not as strong or comfortable on the bike and don’t feel both sides of my knees are loaded how I like so I run shorter than the .883” measurement. As to crank size mattering for this convention…it doesn’t affect it much and if you want you can plug in the 2.5-5 mm delta or use the equation of 1.09 X cycling inseam which is the complement of .883 X inseam which results in the same saddle height.
Its been written before in other related threads but because of the variablility of sit bone position on each person's anatomy, seat deflection under load etc, the best teacher aside from just riding the bike and experimenting I believe is amount of knee angle at the bottom of the stroke. Here too accounts for much variablility in what is considered normal or desirable. The generally accepted range is a rather large 10 degrees or 25-35 degrees with nominal target being 30 degrees. Believe many racers run less angle at the bottom to maximize extension or downstroke power but some run a full angle with a bit more emphasis on their quad strength. A simple protractor with a friend on a trainer will tell you how you measure.
George