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    Faith-Vigilance-Service Patriot's Avatar
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    Inseam vs. saddle height.

    This is one that kind of rubs me the wrong way. i have tried a few online calculators, and they are very close to giving me the geometry that seems most comfortable for me. However, one measurement still makes me scratch my head. And that is the BB center to top of saddle measurement.

    Now, I have a 35.5-36" inseam, and every calculator I have tried tell sme the best range for the BB-center to top of saddle is around 33-34". Now, I have both my bikes set up at 32-32.25" saddle height, and for some reason, I feel like I am getting enough extension, even though it almost 1" lower than every calculator suggests. As one would want, with my pedal at the bottom of the stroke, and my foot parallel to the ground, my knee has a slight bend. If I lock my knee, then my heel drops below the pedal spindle.

    So, what I am wondering is what you all have your saddles set at, to give me a bit of a comparison. What is your inseam, and what is your BB-center to top of saddle measurement in comparison?
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    Infamous Member chipcom's Avatar
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    Quote Originally Posted by Patriot
    This is one that kind of rubs me the wrong way. i have tried a few online calculators, and they are very close to giving me the geometry that seems most comfortable for me. However, one measurement still makes me scratch my head. And that is the BB center to top of saddle measurement.

    Now, I have a 35.5-36" inseam, and every calculator I have tried tell sme the best range for the BB-center to top of saddle is around 33-34". Now, I have both my bikes set up at 32-32.25" saddle height, and for some reason, I feel like I am getting enough extension, even though it almost 1" lower than every calculator suggests. As one would want, with my pedal at the bottom of the stroke, and my foot parallel to the ground, my knee has a slight bend. If I lock my knee, then my heel drops below the pedal spindle.

    So, what I am wondering is what you all have your saddles set at, to give me a bit of a comparison. What is your inseam, and what is your BB-center to top of saddle measurement in comparison?
    Dude, when it comes to saddle height, calculators can only give you a starting point, the fine tuning is up to you and what works best for you.
    "Let us hope our weapons are never needed --but do not forget what the common people knew when they demanded the Bill of Rights: An armed citizenry is the first defense, the best defense, and the final defense against tyranny. If guns are outlawed, only the government will have guns. Only the police, the secret police, the military, the hired servants of our rulers. Only the government -- and a few outlaws. I intend to be among the outlaws" - Edward Abbey

  3. #3
    Dude wheres my guads? skinnyone's Avatar
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    Dunno much about your problem... Can you give a linky to some of those calculators.. I want to try a few myself...

    I have a 35 inch inseam... I measured parallel to the seat tube and I get 31.5"... This is after an elaborate fit and a couple of checks to make sure I am ok...

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    Senior Member NealH's Avatar
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    I have a 91cm inseam (bare feet on floor) and, ride an 81cm saddle height (Sidi shoes, SPD-SL cleats). I've tried 1/2cm above and below but, the 81 works and feels the best in regards to extension. As "chipcom" mentioned, those on-line calculators only give you a starting point so don't take them to the bank.

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    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.
    Last edited by Longfemur; 09-23-05 at 07:37 PM.

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    Faith-Vigilance-Service Patriot's Avatar
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    I guess what I am saying is, I know the calculator is just a starting point. I have known that for a long time. What raises my curiousity, is what the differential is for the riders on this forum. Comparing it to your riding style, and why you think it works best for you.
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    Killing Rabbits
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    Consider this:

    Having your seat set too high will cause more damage to your knees than having it set too low.

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    Senior Member patrick07's Avatar
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    30" pants inseam. 715 mm from saddle to center bottom bracket using SPD-SL pedals and cleats.
    ...

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    Senior Citizen Discount fixedfiend's Avatar
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    sounds right to me. my inseam and seat height are exactly 2" shorter than yours.
    using 175 cranks.

  10. #10
    "Great One" 53-11_alltheway's Avatar
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    Quote Originally Posted by Patriot
    This is one that kind of rubs me the wrong way. i have tried a few online calculators, and they are very close to giving me the geometry that seems most comfortable for me. However, one measurement still makes me scratch my head. And that is the BB center to top of saddle measurement.

    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)
    "The Iron never lies to you. The Iron will always kick you the real deal. It never freaks out on me, never runs. Friends may come and go, but 200 pounds is always 200 pounds." -Henry Rollins

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    Senior Member biker7's Avatar
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    Quote 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.



    Quote 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
    Last edited by biker7; 09-24-05 at 06:19 AM.

  12. #12
    Senior Member Retro Grouch's Avatar
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    Couple of things.

    1. So what's your crank length? If your base measurement is from the center of the bottom bracket spindle, differences in crank length are being ignored.

    2. How did you measure your leg length? Body parts are hard to measure with plus/minus just a few millimeters accuracy. The same thing can be said about the distance to the top of your saddle. Where, exactly, do you measure to?

    3. What are you trying to accomplish? Are you trying to make some bike fitting formula maker happy or do you want to make yourself happy? The purpose of the formula is to short-cut the process of finding the saddle height that makes you happy. You should let it be your servant rather than make it your master.

    If you want a nice analog saddle height system, try this: Go for a ride with someone whose judgement you trust. If your hips rock from side-to-side when you are pedaling, your saddle is too high. If your heels drop below your pedals at the bottom of the stroke, your saddle is too low.

  13. #13
    My toilet-Floyd's future
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    What raises my curiousity, is what the differential is for the riders on this forum.
    The differential will be determined by the way the rider uses the foot, and sadly most people are unaware of how they use this - hence I think the data would be a bit useless.

    FYI my inseam is 91.7 cm and my BB centre to seat top is 80.5 cm

    My legs are at a perfect 30 degree angle when the pedal is at the bottom of the stroke, and my knee is over the pedal spindle when the pedal is at 90 degrees.

    The irony of this is that I set up my seat by feel rather than a formula.

  14. #14
    Senior Member DannoXYZ's Avatar
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    Here's some info I posted a while back. Has links to various calculators, which vary by over 1" based upon my inseam. I'm with EURO, I've adjusted my saddle-height by feel over the years to give me the least amount of knee-pain and best power. In doing time-trials, I've also found that the higher-saddle gave me faster speeds, although I tend to sit further back than the even higher & forward position of triathletes. The way I measure it is to put the pedal at the very bottom (crank parallel to seat-tube), then place my heel over the pedal-spindle with a perfectly straight leg. I adjust to have a 0.5-0.75cm gap between my heel and the pedal.

    The pointing-down of the toes gives another couple inches to the bottom of the ball of the foot. Just went out and measured to verify and my inseam is 27.5" (book under the crotch method) and my saddle height is 32.5" (top of seat to top of lower-pedal, crank-parallel to seat-tube). Measured my track bike and top-of-seat to top-of-pedal is 33".

    1. I originally used the Dave Moulton method of setting my saddle height. I chose it after talking with him at length at a CABDA show back when I was just starting out and had some knee-aches. We discussed it for hours and he was very thorough with explaining the various "whys" of his fitting philosophy. So I taped a 1x2" piece of wood to the top of my pedal (it's really only 0.75" thick). Adjusted my seat so that my heels touched the wood on both sides without rocking the hips and that ended up with the saddle height of 32.5" or +5" over my inseam.

    2. That is taller by about 1" than the method that the Colorado Cyclist recommends. Their number of 31.5" to the pedal top (account for crankarm length of 172.5mm - 0.5" for pedal height) is about 4" longer than my inseam.

    3. Here's another Frame size & Seat Height calculator. I don't understand the logic behind measuring from the top of the seat to the center of the bottom-bracket spindle. The seat height HAS to take into account the crank-arm length. This method comes up with a figure of 31", about 3.5" longer than my inseam. Both the #2 & #3 methods are based on the Lemond method, but it's way too simplistic. It doesn't atake into account individual leg-segment lengths like the femur and it doesn't account for crankarm length.

    4. Yet another seat-height method on SBRAweb which recommends 1.09 * inseam for a figure of 30"; about 2.5" longer than my inseam.

    Remember that you do not ride with your heels on the pedal. The ball of the foot extends down much further and brings the calves into play.

  15. #15
    Faith-Vigilance-Service Patriot's Avatar
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    Hmmmm....

    With all of this said, that Total Bike calculator says I should have my saddle height at 32", which is exactly where mine is at. I do have to admit, I have been getting some patella pain recently. I am thinking of lowering the saddle a couple mm at a time, down to 31.5" just to see what the effect is.

    I personally have always enjoyed a slightly lower saddle anyway. I think with as much commuting I now do, that comfort is becoming more important than trying to maximize my speed an performance on a constant basis.

    If I cruise on the flats during my commute at 18-20mph, instead of 0.5mph faster, then it would be worth saving my knees I think. I have never had serious problems until I started commuting as many miles as I do now, and I believe that 135mi/week is not too much, since I am in fairly good shape. I am thinking the saddle height is one of my problems here. I have just been debating on exactly how to proceed.

    I have learned so much about cycling, but I will be the first to admit, asking simple questions, and getting back to some basics by getting the veiws of multiple people has always given me the best overall answers when trying to come to a concensus as to how to proceed on something as simple as an issue like this.

    Sometimes, being as obsessed with cycling as we are, we all have a tendency to overcomplicate things, and getting some basic answers is sometimes all we really need.
    Last edited by Patriot; 09-24-05 at 09:12 AM.
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    "Great One" 53-11_alltheway's Avatar
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    Quote Originally Posted by biker7
    Worthless?
    Yeah it's straight up worthless. You know why? If crank length is not taken into account then it precisely gives you the wrong answer.

    EDIT: Like I say in the post a couple down, not only does crank length modify maximum height so does fore/aft.
    Last edited by 53-11_alltheway; 09-24-05 at 09:23 AM.
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    "Great One" 53-11_alltheway's Avatar
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    Quote Originally Posted by Retro Grouch
    Couple of things.

    1. So what's your crank length? If your base measurement is from the center of the bottom bracket spindle, differences in crank length are being ignored.

    Exactly, the crank length determines the location of the pedals which is more relevant than the BB center.

    BB center measurements are fine if all cranks came as 170mm (for example) and there is no devaition.
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    "Great One" 53-11_alltheway's Avatar
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    Is this a saddle height formula that doesn't even take into account fore/aft?

    The maximum saddle height you can tolerate is also dependent on the seat set-back? Why? Because increasing seat set-back increases distance to the pedals and thus limits maximum saddle height.
    "The Iron never lies to you. The Iron will always kick you the real deal. It never freaks out on me, never runs. Friends may come and go, but 200 pounds is always 200 pounds." -Henry Rollins

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    Faith-Vigilance-Service Patriot's Avatar
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    The saddle height formulas are basically a measuement from the center of the BB, straight up the seat tube to the top of the saddle directly above, regardless of how much setback is used. That is adjusted according to personal preferance taking into account your femur length.

    I know this may seem strange, but I tend to think that crank length is not quite as large a factor as you are eluding to. Mainly because the crank length usually only differs by a 0-5mm (<0.25") from 170 to 175. This, when the saddle height recommendations are given in 1/2" incraments. But like we have all said, it is just a good starting point. Where you go from there is up to you.
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  20. #20
    "Great One" 53-11_alltheway's Avatar
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    Quote Originally Posted by Patriot
    The saddle height formulas are basically a measuement from the center of the BB, straight up the seat tube to the top of the saddle directly above, regardless of how much setback is used.
    Well, this is exactly what I'm talking about. Why be precise with a formula that leaves out 2 critical variables.

    Those variables are far more important than you think. I know this because I have messed around with 170-180mm cranks. I can also tell you that a few cms difference in set-back has a bigger impact on saddle height than you think (distance in the X plane is not independent to distance in the y plane)

    The biomechanics are what you need to be thinking about because that is really what matters. Try visualizing this stuff in your mind because that helps a lot when dialing this in. That and using your own feedback you notice when turning the pedals in a circle.

    Retrogrouch was right when he also recommended someone get behind you to watch your hips (that can help detect too much ankling or downward pull by the pedals)

    Just my two cents (as usual)
    Last edited by 53-11_alltheway; 09-24-05 at 09:54 AM.
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    Faith-Vigilance-Service Patriot's Avatar
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    I know setback is a big variable. By moving my saddle back ~1" from center, my height changed by about 1/2" from where my sit bones sit, but not the height from the BB center to the top of the saddle directly above the seat tube.

    Anyway, in my case, I run with my saddle setback quite a bit because my femur length is around 24.5" when measured against the wall to kneecap at 90deg.

    This is why my thought are moving in the direction of needing to lower my saddle, because I sit back so far on the saddle, so my saddle height is effectively increased when doing so. Because of my long femurs, I use alot of glute muscle and quads (even hamstrings) when seated. When standing and climbing short hills, that's when I really feel the calves kick in.
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    "Great One" 53-11_alltheway's Avatar
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    Quote Originally Posted by Patriot

    This is why my thought are moving in the direction of needing to lower my saddle, because I sit back so far on the saddle, so my saddle height is effectively increased when doing so.
    This makes sense.

    Your legs are only so long, so if you had long femurs and short tibia for example you could make an argument that ***relative to your riding position*** more distance would have to be in the form of set-back vs saddle height. (ie, distance in horizontal plane vs vertical plane)

    Of course we all know that you can rotate about the BB too which modifies things, but the relationship as a series of levers and pivots still remains essentially the same biomechanically.
    Last edited by 53-11_alltheway; 09-24-05 at 10:12 AM.
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    Senior Member 55/Rad's Avatar
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    I do it by feel and my "feel" can change from ride to ride, depending on how I feel. this is why I have QR's on my seatpost clamp. I will often alter saddle height (by as much a foot or 2) on any given ride.

    OK, maybe a MM or 2.

    55/Rad

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    Senior Member biker7's Avatar
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    Quote Originally Posted by 53-11_alltheway
    Yeah it's straight up worthless. You know why? If crank length is not taken into account then it precisely gives you the wrong answer.

    EDIT: Like I say in the post a couple down, not only does crank length modify maximum height so does fore/aft.
    I am pretty astounded by what you wrote 53-11. I frankly expected you to be a bit more on board...well...maybe not especially the part about how set-back is not taken into account with Lemond's formula. 53...it is an acute right triangle. Set-back from the BB is the horizontal leg, vertical height from BB to top of saddle is the vertical leg and Greg Lemond's formula i.e. .883 X inseam is the hypotenuse which takes into account set back....it is a function of set-back. Will say it again...the Lemond formula is a function of set back for distance from top of saddle where you measure to the BB. Of course where Patriot sits on his seat affects distance to the BB...it is part of the Lemond formula. If Patriot sits on the far rear of the seat, you measure to where his sit bones contact…which includes how much set-back he is using. As to crank length affecting the formula...not much. If you don't like Lemond's formula, then use Harnley's formua of 1.09 X inseam which takes into account crank length. You end up with virtually the same result give or take a few millimeters...that is...a seat height higher than most cyclists ride except elite racers....1.05 is a more typical norm.

    You heard it here first. 53-11 thinks that the TDF champion Greg Lemond’s formula is bunk.
    George
    Last edited by biker7; 09-24-05 at 11:04 AM.

  25. #25
    "Great One" 53-11_alltheway's Avatar
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    Quote Originally Posted by biker7
    53-11 thinks that the TDF champion Greg Lemond’s formula is bunk.
    It is bunk because it is too simplistic. Crank length/pedal stack height/ shoe sole thickness isn't accounted for. WTH?!?!? (Hint the saddle height difference between a 170mm and 180mm is huge in relative terms for any given leg length)

    Besides Patriot claims the formula he is using doesn't even take into consideration seat set-back. (adjustment on the seat rails is independent of the formula WTH?!? again! )
    Last edited by 53-11_alltheway; 09-24-05 at 11:32 AM.
    "The Iron never lies to you. The Iron will always kick you the real deal. It never freaks out on me, never runs. Friends may come and go, but 200 pounds is always 200 pounds." -Henry Rollins

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