seat height
 

Is there some type of ratio as far as seat height goes. Example, if you have a 34" inseam should the bottom of your saddle be about 34" away from your pedal when it is at its lowest point?

Coud be, but it would need to take into account, at least, the sit tube height and the crank arms length. I position the saddle the "old fashion way". Sitting on the saddle, right leg on the pedal with RHS crank arm aligned with the seat tube and in lower position, your leg should be nearly straight meaning the knee is slightly bent while your foot back sole is lowered. Then sitting straight on my bike, each feet's toe ends should touch the ground but no more. It works for me, but am sure other people have other methods. And to be honest with you, I end up changing the height after the first couple of rides until I feel comfortable. ;)

Not really; there are too many other variables. Foot size and shape. Amount of "butt padding." Preferred saddle fore/aft position.

The good old method works for most people. Start with a height that yields a straight leg when you put your *heel* on the pedal at its lowest position. When you move the ball of your foot to the pedal, your knee will now be bent. If this height lets you ride without rocking side to side as you pedal, try it. If you rock, drop the height no more than a quarter-inch at a time until you don't.

RichC

Some of the seat-height formula are based on a % on inseam. These can give results to less than 1mm precision. Usually they ignore crank length, pedal and shoe thickness, saddle padding, all of which can add up to an extra cm or so.
Dont take any formula too literally.

This is from the Greg LeMond book "The Complete Book of Bicycling" I did it and it made alot of difference in my stroke, speed and endurence.

" How to Fit Your Bicycle

If you're too low on the bike, your legs will be bunched up and you won't be able to use their full muscular force. In addition, you'll be straining the legs because they will have to work harder to achieve the same speed; you will tire out much more quickly. In addition, the strain from the muscles will act as a source of stress for all your connective tissue-ligaments, cartilage, and tendons.
If, on the other hand, you're riding too high, you will stretch out too much and you won't be able to achieve full power in the crucial down stroke of your pedaling motion. In addition, you'll be constantly overstretching the muscle and connective tissue of the legs-a ripe situation for muscle pulls and connective tissue injury.
(If all this sounds terribly serious, to put it in perspective you could probably hurt yourself much more easily by running in the wrong shoes, because running is much harder on the body than cycling.)
Finding the right position, in fact, should be quite easy. To measure your overall height, you begin with the same inseam measurement you used to determine your frame size. Next, take that number and multiply it by .883, This figure was developed by French coach Cyrille Guimard. It's the result of numerous tests and years of experience with professional riders. My inseam is 84.3 centimeters; multiplying it by .883, I get an overall height of 74.4 centimeters, or 29.3 inches. That is the overall distance, in a straight line, from the center of the bottom bracket to the top of the saddle. Remember, though, that what's meant by the top of the saddle is the cupped part where you actually sit, not the lip that rises to the back of the saddle.
To determine your overall height, adjust the seat post and saddle so that the total distance from the center of the bottom bracket axle to the top of the cupped part of the saddle is your overall height measurement. In my case, if I adjust my saddle correctly, that distance is 74.4 centimeters or 29.3 inches.
Remember that this overall height formula was determined with the standard Campagnolo racing pedals and standard, medium-thickness cycling shoes such as Brancale, or Sidi nylon mesh shoes.
You should always measure any distance in a line parallel with your seat tube. Since your crank set sticks out farther than your saddle you'll need to add two or three millimeters to your measurement when using the tape measure, or you'll get a shorter overall height measurement.

Which means it's a crock. Unless you have those shoes and those pedals. And Greg Lemond's physique.

RichC

I adjust my seat the same as Cycliste. Overall it is really trial and error untill you find the height that you like.

I dont see how its a crock :confused: this should give you a good baseline to get started. I didn't copy the whole chapter but, it's backed up by science, You think Lance Armstrong gets on his bike and adjusts things until they feel "right", I dont think so, they test this stuff, over and over, recording the results, and test again.

LeMond also says, " There are a couple of additional, but important, things to keep in mind. The overall height formula assumes that you ride in cycling shoes with an average sole thickness. Even though you measure yourself only in socks, the formula is calculated to include the thickness of your cycling shoes (presumably you never ride in bare feet). But if you have a pair of those Italian cycling shoes with the thick, wooden soles, you'll have to add the difference between the average sole (like Brancale) and your soles to your frame height. In other words, Adidas shoes-to take Huggi's model-have a sole thickness of about twelve millimeters (including the thickness of the slot on your cleat). If your model has a sole that measures, for example, twenty-two millimeters, you'll have to measure the difference between the twelve-millimeter standard used by Huggi and your shoe. Then subtract the difference from the overall height measurement. If your soles are thinner than the Adidas models, you need to add the difference in thickness to the overall height.
The best way to measure the soles of your shoes is to take a pair of calipers and measure your soles at the center of the ball of the foot. Be sure to put the calipers through the slot in your cleat-remember you want to measure everything as it would be on the bike. If you can't do that, take a piece of string, estimate the thickness of the sole at the center of the ball of your foot (including the slot in the cleat). You can then measure that string with a ruler.
If you are extremely concerned about exactness, measure the thickness of your cycling shoe soles. But really, it's not going to make a big difference. Remember, when you're within a centimeter of your correct overall height measurement, you'll be fine. Also, external factors like shifting your position on the saddle and riding in wet cycling shorts will change your position a little anyway. Don't get overly hung up on the minor details of setting up your position-if you do it could become a psychological crutch.
The overall height formula also assumes that you're going to ride with the standard-length 170 millimeter cranks. Of course, you may ride with different cranks, depending on your needs and personal preference. The reason for changing crankarm lengths is to get more leverage (with longer cranks) or more speed (with shorter cranks). If you change your overall height to accommodate the difference in crankarm lengths, you'll reduce the added leverage or speed you could get with a different length of crankarm.
The formula for overall height that I describe here is calculated for 170millimeter crankarms. But I ordinarily ride in 175-millimeter cranks and still use the same measurement. "

This is an old book and yet alot of people still go by these "baselines"

Dont forget, This guy was the first American to win the Tour de France, 3 times, and came back from a near fatal gunshot wound. He also helped design the shifters we use, the cycle computer and a lot more that makes the bike that we ride today.

Bottom of stroke,knee slightly bent.There's your baseline.Dont make something thats not that hard,a really big deal.

Everyone's physiology is different; what works for LA probably won't work for me. There's not a formula to follow, but there are lots of places out there to find a good starting point. You can also put in all of your measurements to some online resources and they'll spit back a starting point. They'll claim that it's where to set what, but it's really just a place to start your bike fit. Trial and error, or a professional fit, is the way to go.

Shokhead, I'd say that saddle height adjustment, while not hard, is worth making a big deal out of.

I bet if Lance got on his bike and it didn't feel right, he would adjust it!

Aston, my point is that (as illustrated by your second quote from LeMond) any formula is just a starting point. Greg says he uses the formula, but his cranks add 2.5mm to his leg extension. Well, that pretty much turns the formula into "just as starting point" right there, doesn't it?

And IMO his willingness to accommodate 3/8" of slush in the measurement pretty much makes it voodoo science anyway. That much change in saddle height definitely matters, and it's something you can feel, that affects comfort.

No professional cyclist accepts the results of a formula over their own perceptions. Sure, they'll use the formula or some other method to establish the starting point, and a rider with Lance's resources will have ways of collecting data to assess the impact of any changes he makes to his bike, but what's true for any commuter or club rider is equally true for a pro: if it hurts, it negatively affects performance.

I don't dispute that sometimes the formulae can yield perfect results. But that statement is equally true of a variety of formulae from different sources, all of which use different numbers and yield different results. If the formula you happened to try first got you a perfect saddle position, then congratulations on your luck. Be glad you didn't read someone else's book first.

RichC

You better believe he does, he's known for hopping on and off his bike making 1/2 mm adjustments until everything feels just right, and he's known to do that for days on end during the tour depending on how he feels.

But that's only half the story, he positions himself on the bike according to his "fit" expert, for TT duties they then go into the wind tunnel and tweak it all, etc. So yes, he's using science and technology to the very limit, but to him it's still a "starting" point.

But using LA as an example really doesn't work for the rest of us, the guy puts more miles on his bike than the average American puts on a car in a year. So he's going to be much more in tune with what he likes and dislikes. As an extreme example, anybody notice his TT frame this year? How it's different than the rest of the team (and what's available from Trek), it's an old 2001 model painted to this years specs. The reason given why he's riding that old thing....he likes the feel of the bearings in the headset.

Me? I can barely tell when they need to be serviced, and I bet if you lined up 10 identical bikes, all sized the same, everything else sized the same (seat height, stem length/angle, etc) I wouldn't be able to tell them apart.

When I set my seat height, I used one of the formula's out there to get me in the ballpark, except it was to high (I use longer cranks), so I tweaked from there.

Andrew

my method: i had my LBS fit me.

and then when my knees started hurting, i adjusted it. :)

little things can make a difference, so it really is a matter of getting it in the ballpark and then adjusting it based on how it feels.

one thing no one ever mentioned to me: when you adjust your seat height, you probably want to adjust the fore/aft position of your seat too. moving your seat up also moves it back, because of the angle of the seat tube.

i was getting a bit sore right above my knees, in the tendon area where my quads meet my knee (if i've got my anatomy right). so i raised my seat by 1/4" (.5 cm). immediately i started getting pain under my knee caps. then i did a little reading, found out about knee-over-pedal placement, and moved my seat forward by the same amount. this seems to be helping, although i may end up making another adjustment.

and now i want to fiddle with my stem because i'm a little bit closer to the bars. but that's a topic for another thread...

Thats what i'm doing right now,stem research.I need to raise by bars.

my LBS installed my stem in 'newbie' position. it's a Ritchey stem that can be flipped to be either higher or lower. i'm actually thinking about flipping it lower, which will give me some more reach and also get me more aero. at the price of back-ache comfort though, so i haven't done it yet.

if you've got road bike bars, you could rotate the bars upward a little, which would make the brake hoods higher (which is where you ride the most probably). that's free, which is better than buying a new stem. if you've got hybrid or MTB handles, that's not an option.

Help me figure this one out:

I was riding behind a guy on a MTB and when he would stand up to pedal the tip of his seat was about level with his waistband. He would stand up straight as a rod when he pedaled and the whole thing just looked strange. Going from standing to sitting he almost had to leap back up to be seated. When seated it did look like his legs were extended on the down stoke a little too much.

When I'm standing the point of my seat is level with the bottom of my back pocket.

Anyway, was the bike just too big for him or was it simply a matter of a seat being positioned too high?

Pure rocket science. That's my method above as well.....works for me every time.... :)