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Let's talk about saddle position (fore-aft, up-down)(7 posts)

Let's talk about saddle position (fore-aft, up-down)bill
Apr 15, 2002 10:21 AM
I've been reading up a bit on saddle position. Not only have I been trying to dial mine in just right, but I've also been trying to understand the mechanics/physics of it all, so that I might be able to predict what effect on my pedaling, balance, etc., certain movements of the saddle may cause.
I started with Sheldon Brown and his links (including Keith Bontrager, others). I read Zinn's little blurb in his mechanics book. Other stuff. What I've decided is that there is a lot of myth out there and not a whole lot of analysis. For example, Bontrager dismisses the whole KOPS mantra as an approximate, serendipitous starting point having nothing to do with pedaling mechanics and much more to do with sizing the cockpit over a balance point (although his method for balancing the bike, to the extent I understood it, seemed completely unwieldy, involving locating a crouching body's center of gravity and positioning that center some distance known to him and a few acolytes a few cm from the 9:00 pedal spindle position), while others assert that KOPS itself is not mandatory but "proper saddle placement in relation to BB" is for good pedaling mechanics is. Then there are those who talk about "long femurs" and "low-mass upper bodies" without explaining why these things matter or how to use this knowledge and develop a fit (what is considered a long or short femur?)
And then saddle height. Some authorities seem to advocate the highest you can get away with without hurting yourself. The formulas others use place me, if I'm understanding the formula, a good 2-3 cm below where I now am riding (more than could be accounted for by differences among pedals, shoe soles).
Feel free to pop in any time.
I subscribe to the whatever works for me theory..Lone Gunman
Apr 15, 2002 10:48 AM
I put my bike in the trainer, making sure the top tube is level and start from there. I go for height first by doing the heal on pedal at the bottom of the arc with me seated level on the saddle, then I try to get the saddle a touch above level to keep my hips back and weight off of my hands then I start with the saddle in the middle for to aft position and work on that till I am comfortable. IMHO I throw the theories out and use my own.
Whatever works best seems to be the way for most...LLSmith
Apr 15, 2002 11:36 AM
I have to keep mine about 3/4" behind the KOP position. Any closer and my left knee hurts. As soon as I move it back the pain goes away. Not sure if I am getting all the power, but no pain is much better for me. Been thinking about getting a new bike built so it can be set up to compensate for all my little quirks.
my very unscientific opinoin.SteveO
Apr 15, 2002 10:53 AM
most measurent systems were developed to acheive a specific goal (comfort? aerodynamics? power output? handling?).

Since no 2 bodies are alike, no single measurement system can isolate 'optimal' positioning for the masses.

For most riders, the most important aspect is comfort (since the more comfortable we are, the longer we can ride with greater output). Therefore, i believe the aged-old comfort-fitting techniques should be a starting point (.65 frame, .883 height, blind hub, etc), but certainly not taken as gospel.

Once a comfortable fit is acheived, individual biometric feedback is far more valuable than any set of equations (which is evidenced by the fact there are so MANY formulae out there). Small adjustments should be made to 'dial in' your desired goal.

In your specific example, where is your current saddle height and what is your goal?. If you've tried 'the highest you can get away with', and your not achieving your goal, by all means tweak it's position by use of another model. Did that help or hurt? you get the picture.

guess what im trying to say is,,,, most models are built around a specific person or group of people who were studied for a specific result; dont sweat the particulars as that particular model (most probably) wont represent your body 100 percent.

its all about trial and error.
I guess what I'm asking/wondering is, saddle too high means ...bill
Apr 15, 2002 11:32 AM
what? I've heard people say that you get more power from a higher position, but why? is this right? I look at the pros, and I see lots of different knee angles at the bottom of the stroke. Is that because of "different length femurs" or something? The saddle too far forward means . . . what? What do you lose? What do you gain? Etc., etc.
re: Let's talk about saddle position (fore-aft, up-down)DINOSAUR
Apr 15, 2002 11:20 AM
I do subscribe to the KNOP theory. There is a big difference between 1 cm behind and 1 cm ahead. I was riding with a 1cm behind KNOP for about a year and I switched to a neutral position as I found myself scooting forward on my saddle when climbing while seated. After I found my prefered KNOP, it took about a year to determine the stem length/rise. I also found that my saddle was too high, and most settings have my position way too low.

I sort of set my bike by following guidelines then I carry a hex wrench with me and make little adjustments going with what my body tells me. Little changes, however small can make a big difference, such as the tilt of your handlebars.

I think you can get away with a bad fitting bike when you are younger, but when you get in your 50's a bad fit can lead to injury very quickly. The best way to start out is with a frame that fits you to start with, followed by a STA that will dial in with your preferred KNOP, then TT length. I also found that saddles come with different length rails and finding the right saddle has more to do about just being comfortable. I prefer to level mine out, then tilt it back one click using a small carpenters level to double check.

All the debates about frame material is a big waste of time. It comes down to fit and geometry, combined with a bunch of experimenting. It's not one-fit-for-all. I think the femur length is dependent on your over-all height. I'm 6-0, and have a 34.25 inseam, long arms and a short torso, which is probably consistant to most tall guys. I was sized once for a 57cm, which is too small for me, I feel more comfortable riding a 58 or 59, but the TT is the important measurement for me.

This topic could probably be discussed until the suns goes down. It has to do about anatomy, range of motion, flexibility, and technique. The best teacher is experience, and experience is another word for mistakes.

An old roadie told me once to dial in my bike going with what my body told me, probably the best advice anyone ever gave me..
re: Let's talk about saddle position (fore-aft, up-down)Krypton
Apr 15, 2002 11:21 AM
Yes, lets talk about it...

Everybody is different, no one size fits all formula will work. In '92 when I bought my Allez carbon, I bought it to race duathlons. I had aerobars and a very forward saddle position. I could hammer real hard without any problems. Then, in '95 I hurt myself running and could not bike until '98. When I started again, I decided to put on normal bars and seatpost and gradually move my seat position back. A year later, my left knee started hurting, just occasionaly at first but it got worst. I was kind of a burning sensation and feeling my left leg was not as strong as my right. I rode for two years with the pain and playing with different saddle heights. Finaly, I changed my saddle to one that as longer rails and I push it forward gradually and now, the pain is almost gone, the power is back.

If I was to use the different formulas out there for my saddle position, I would have to put it back about 4mm, but I know it will hurt my knee again so I leave it just the way it is.

So I guess, we are all much different, so we have to experiment to get to what feels good for us.