# Knee Bend Degree



## shanabit (Jul 16, 2007)

What is the normal range for the knee bend assuming cycling shoes on/clipped in and the crank at bottom dead center? 15, 20, 25, degrees ? Thanks. Trying to get my wife setup and I cant remember


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## charliepuyear (Oct 7, 2011)

32 degrees is perfect. Under 30 and your not getting enough power into each stroke, over 35 and your getting more power but also risking knee injury and will lose stamina. 32 is the happy medium and ideal.


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## cyclequip (Oct 20, 2004)

charliepuyear said:


> 32 degrees is perfect. Under 30 and your not getting enough power into each stroke, over 35 and your getting more power but also risking knee injury and will lose stamina. 32 is the happy medium and ideal.


Incorrect I'm afraid. FWIW you can use a range between 25 and 35 degrees as nominal, but knee angle is best set dynamically, with the rider warmed up and riding at medium cadence (80 - 90 rpm) under a medium-high load. The actual angle range will be determined by rider flexibility and pedal style.

Then it's a question of making sure the rider is keeping control of the pedal for the duration of the pedal-stroke and is not losing/catching the pedal at BDC - best seen as a micro-acceleration jn the heel-rise or of the rear of the thigh/knee through BDC.


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## charliepuyear (Oct 7, 2011)

cyclequip said:


> Incorrect I'm afraid. FWIW you can use a range between 25 and 35 degrees as nominal, but knee angle is best set dynamically, with the rider warmed up and riding at medium cadence (80 - 90 rpm) under a medium-high load. The actual angle range will be determined by rider flexibility and pedal style.
> 
> Then it's a question of making sure the rider is keeping control of the pedal for the duration of the pedal-stroke and is not losing/catching the pedal at BDC - best seen as a micro-acceleration jn the heel-rise or of the rear of the thigh/knee through BDC.


Excuse me. I was speaking about what fit for me personally. I'm sure your correct.


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## dmong2 (Sep 14, 2011)

This might be the least useful number to try to hit while fitting a person. 

How can you really even accurately measure anyway without being able to see the bones in question? 

The angle will change quite a lot as you ride because of heel drop. Heel drop will change with effort, ability to control, pedal style/efficiency, and cadence. 

Seat height is really not that important unless it is too high (most common mistake) or too low. There is a range that works fine, but I would recommend to err slightly on the low side rather than the high.


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## Peanya (Jun 12, 2008)

34 to 35 is what feels ideal to me, according to the fit measurements.


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## Kontact (Apr 1, 2011)

Pruitt and others usually suggest a range of 25 to 30 degrees, so it is surprising to hear people throwing 35 around.

You can measure your knee, you can use a formula based on cycling inseam - they all produce very similar results. Whatever specific angle you end up with is a function of crank length and your anatomical needs, not an exact number. I've had great success with the .883 formula with a lot of people, but I'm not a dynamic fitter, just trying to get people into the right range when they weren't even close.


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## cyclequip (Oct 20, 2004)

Kontact said:


> Pruitt and others usually suggest a range of 25 to 30 degrees, so it is surprising to hear people throwing 35 around.
> 
> You can measure your knee, you can use a formula based on cycling inseam - they all produce very similar results. Whatever specific angle you end up with is a function of crank length and your anatomical needs, not an exact number. I've had great success with the .883 formula with a lot of people, but I'm not a dynamic fitter, just trying to get people into the right range when they weren't even close.


Actually Pruitt suggests 25 to 35 degrees, not 30. 
30 is neutral.


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## RJP Diver (Jul 2, 2010)

dmong2 said:


> Seat height is really not that important unless it is too high (most common mistake) or too low.


So you're saying that seat height doesn't matter as long as it's set properly?

:thumbsup:


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## wim (Feb 28, 2005)

dmong2 said:


> Seat height is really not that important unless it is too high (most common mistake) or too low. There is a range that works fine, but I would recommend to err slightly on the low side rather than the high.


Agree. Unlike the much too-low position you'd often see back in the days of the 30-second bike shop "standover fitting," nowadays I see more and more people riding much too high. Not entirely sure why that is, but I suspect bad web site advice ("full leg extension" and other misleading catch phrases).


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## sp3000 (Jul 10, 2007)

I find that fit is a very personal thing and every body is different. A good starting point is to set the saddle to the point where her hips have to lean to make the full crank rotation, from here drop the saddle to find the point where her hips are stable and don't need to move to make a comfortable pedal stroke. This worked for me and solved lower back problems, I only needed to drop the saddle by 5mm to make a big difference, but as Chubbs says, "it's all in the hips".

I'm sure people will shout me down for my method, but I'm internet tough.


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## wim (Feb 28, 2005)

sp3000 said:


> A good starting point is to set the saddle to the point where her hips have to lean to make the full crank rotation, from here drop the saddle to find the point where her hips are stable and don't need to move to make a comfortable pedal stroke.


While that works for some, it doesn't for all. You'd be surprised at the number of people who rock their hips even with their saddle much too low or don't rock their hips even with their saddle much too high.


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## MattSoutherden (Jun 24, 2009)

Cyclequip seems to nail it...


... unless you're a hipster riding fixed. Then you need to look for zero degree (fully straightened leg), and toes pointed right down. Must be good. Everyone's doing it. :thumbsup:


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## DL1 (Apr 10, 2007)

cyclequip said:


> Actually Pruitt suggests 25 to 35 degrees, not 30.
> 30 is neutral.


What is "neutral"?


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## swidd (Jul 17, 2011)

Is there a way to measure this myself, not relying on a $75 bike shop program?


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## FTR (Sep 20, 2006)

Hogg basically indicates that there is no correct knee bend unless you are 100% average and symmetrical (which none of us are).


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## wim (Feb 28, 2005)

swidd said:


> Is there a way to measure this myself, not relying on a $75 bike shop program?


Sure. Locate and mark (tape, paint dot) the lateral malleolus of the ankle, the lateral femoral condyle of the knee and the greater trochanter of the hip on one side of your body. Warm up 20 minutes on a trainer, then take a video (minimum: 1 minute) of yourself on the trainer turning a reasonable cadence at a significant power output. Make sure the camera lens is at right angles to you and at the same height from the floor as your lateral femoral condyle. Stop-motion the full-screen clip at the crank bottom dead center (defined as in line with the seat tube). Using a sheet of thin paper or tracing paper, trace the three tape- or paint markings off the monitor. Using a protractor, read the angle formed by the two converging lines connecting the markings. Subtract that value from 180 to get the cycling knee angle.

Problem is: what are you going to do with that figure? As pointed out by others, using knee angle for setting saddle height may not result in optimal saddle height for you.


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## speedking (Oct 12, 2011)

Gotta tinker and try it out if you're not gonna get a fit. I'm good with a 30ish deg


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## FTR (Sep 20, 2006)

Try using Steve Hogg's site and doing it yourself.
I had a chronic back injury for 2 years. Turned out it was from a too high saddle.
Between Chiro and massage (recommended by Steve) and adjustment of my seat height and setback using Steve's method I am now pain free.

Read his blog entries in this order:

The right side bias
Seat Height, how hard can it be
Seat set back for road bikes
Addendum to road pedals, which are best
Power to the Pedal - Cleat Position
Foot Correction Part 1

Also read "Perspectives on Fitting".


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## cda 455 (Aug 9, 2010)

FTR said:


> Hogg basically indicates that there is no correct knee bend unless you are 100% average and symmetrical (which none of us are).


Yeah, I adjust by feel.

Since I'm a heel-dropper I adjust my saddle even lower. Where my leg feels nearly straight at 6 o'clock but with a comfortable bend.


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## cda 455 (Aug 9, 2010)

FTR said:


> Try using Steve Hogg's site and doing it yourself.
> I had a chronic back injury for 2 years. Turned out it was from a too high saddle.
> Between Chiro and massage (recommended by Steve) and adjustment of my seat height and setback using Steve's method I am now pain free.
> 
> ...


I've read most of Steve's blogs. He's pretty awesome.


When I found out how RAAM competitors set up their cleats, Steve's blog further explained how having cleats moved rearward on the shoe helps in power transfer and power efficiency. I moved my cleats all the way back on my shoes as a result of his explanation.


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## FTR (Sep 20, 2006)

cda 455 said:


> I've read most of Steve's blogs. He's pretty awesome.
> 
> 
> When I found out how RAAM competitors set up their cleats, Steve's blog further explained how having cleats moved rearward on the shoe helps in power transfer and power efficiency. I moved my cleats all the way back on my shoes as a result of his explanation.


You need to be careful with "all the way back".
My Sidi's are all the way back but when I did that on my Gaerne's I ended up with calf pain due to the fact that their is more rearward adjustability on the Gaerne's and as a result my "virtual saddle position" had changed.

Since using Steve's methods I have moved my cleats on both shoes by 10mm and have dropped my saddle height by 15mm.
Also moving to Speedplays has helped my knee issues.
At his recommendation I also went to see a Chiro and masseuse about ITB, QL, TFL, Psoas and SI joint issues and am now riding pain free.


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## Fredrico (Jun 15, 2002)

*I think that's a good way.*



sp3000 said:


> I find that fit is a very personal thing and every body is different. A good starting point is to set the saddle to the point where her hips have to lean to make the full crank rotation, from here drop the saddle to find the point where her hips are stable and don't need to move to make a comfortable pedal stroke. This worked for me and solved lower back problems, I only needed to drop the saddle by 5mm to make a big difference, but as Chubbs says, "it's all in the hips".
> 
> I'm sure people will shout me down for my method, but I'm internet tough.


Yes it is all in the hips. Rocking the hips is always a function of over reaching at the bottom of the pedal stroke. Raising the saddle to the point the hips start to rock, then lowering it to the point the hips don't rock anymore is it. That takes into account variations in pedaling style, flexibility, and anatomical quirks, whatever they may be.

I found out my saddle was slightly too high when I was learning how to "spin." I couldn't keep up a cadence above 85 rpm without noticing the hips rocking. I lowered the saddle to the point I could pedal fast with the hips stable, and haven't looked back. Of course, it's helpful, if not essential, to have your feet clipped on the pedals. You'll notice the hips rocking when trying to make circular motions on the crank, much more obviously than only when jamming down.

Turns out for most people, the resulting saddle height will be identical or very close to the LeMond formula, Hgt. = Inseam x 0.883. It will also fall in the range of 26-35 degree knee bend, depending on how this is measured.


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## FTR (Sep 20, 2006)

Fredrico said:


> It will also fall in the range of 26-35 degree knee bend, depending on how this is measured.


So really a pretty huge range could be right for you:


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## Fredrico (Jun 15, 2002)

FTR said:


> So really a pretty huge range could be right for you:


Well the famous Fit Kit, which bike shops have been using for years, says 30 degrees is the right angle.  For some who may be challenged in flexibility, perhaps less is more desirable, until the legs gain flexibility. For others, as Wim suggests, slightly less angles work just fine. But I bet they can't pedal really fast!


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## FTR (Sep 20, 2006)

Fredrico said:


> Well the famous Fit Kit, which bikes shops have been using for years, says 30 degrees is the right angle.  For some who may be challenged in flexibility, perhaps less is more desirable, until the legs gain flexibility. For others, as Wim suggests, slightly less angles work just fine. But I bet they can't pedal really fast!


Wont argue but the international level cyclists that Steve Hogg works with will most likely disagree with you.
30degrees measured where? You could end up with a fairly decent variance depending on how this was measured.
I have had a number of "fit kit" type fittings, BG fittings, dynamic fittings, video'ed fittings etc. None worked for me and I ended up injured ultimately from far too high a saddle.

Read Steve's stuff.
Try it.
It saved me.


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## FTR (Sep 20, 2006)

Question.
What does "until the legs gain flexibility" mean?
This makes no sense at all. to me.
They hang from your hips.
They extend when pushing down and they hinge when coming up.
The part of your body that needs flexibility is your back and hips.


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## Fredrico (Jun 15, 2002)

FTR said:


> Question.
> What does "until the legs gain flexibility" mean?
> This makes no sense at all. to me.
> They hang from your hips.
> ...


Cycling works the legs in circles, at more extreme angles than running or walking. The ligaments around the knees and butt (hips) stretch quite a bit more than when walking or running. The movements stress the muscles in different angles. I've always thought pedaling a bike requires some degree of flexibility of the legs not required in other sports.

And sure, hips and back too, but they're mostly in isometric tension. They're not actually "doing the work."


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## FTR (Sep 20, 2006)

Fredrico said:


> Cycling works the legs in circles, at more extreme angles than running or walking. The ligaments around the knees and butt (hips) stretch quite a bit more than when walking or running. The movements stress the muscles in different angles. I've always thought pedaling a bike requires some degree of flexibility of the legs not required in other sports.
> 
> And sure, hips and back too, but they're mostly in isometric tension. They're not actually "doing the work."


OK I will have to believe you on that.
While not disagreeing that the angles you have suggested may actually work., I do have to wonder whether they are more of a lucky coincidence rather than a fixed number that people should be aiming for.
I have no idea what angle my knees are at during any part of the circles that they go through while I am pedalling.
I do know that I am powerful, reasonably fast, have endurance and am comfortable at the seat height and setback that I am using.
I also know that I do not suffer back pain, hip pain or ITB pain like I did when my saddle was higher.


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## Fredrico (Jun 15, 2002)

*You're fine.*



FTR said:


> OK I will have to believe you on that.
> While not disagreeing that the angles you have suggested may actually work., I do have to wonder whether they are more of a lucky coincidence rather than a fixed number that people should be aiming for.
> I have no idea what angle my knees are at during any part of the circles that they go through while I am pedalling.
> I do know that I am powerful, reasonably fast, have endurance and am comfortable at the seat height and setback that I am using.
> I also know that I do not suffer back pain, hip pain or ITB pain like I did when my saddle was higher.


As others have suggested, everyone has his own anatomy and style of pedaling. If you can go long distances at good aerobic intensities in comfort, and recover easily afterwards, you've got it. :thumbsup:

Adjusting everything by feel is the way to do it, in the end. Formulas and measurements can help identify problems. Setting saddle height by knee angles and inseam is really a starting point, pretty close to the most comfortable and efficient positioning, but there's some adaptation involved as well as tweaking for individual anatomy and pedaling styles. Trial and error, "feel," is the way to find the sweet spot, IMO.

I went through the same problems you did, raising my saddle too high in the interest of powerful stroking (and following the trend in the 80s of riding with saddles jacked way up), then realized lowering the saddle solved crotch soreness, pain on back of leg behind knee, and inability to spin smoothly, and yes, stressed out lower back on longer rides.

Eddy Boresewicz (sp?), the guy who coached Alexi Grewal to Olympic victory in '84, wrote about tests conducted with pros. As saddles were raised, the legs could work as longer levers, taking advantage of a greater range of action of the muscles, thus more power and efficiency. This was up to about 96% of leg length. Above that, efficiency, power, dropped off precipitously. Below 96% the drop off curve was much shallower. Those experiments contributed to the LeMond formula mentioned here. I'd bet if you measured your positioning, your figures would come pretty close to the LeMond formula.


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## FTR (Sep 20, 2006)

It is *exactly *the height I used to ride based on BG/ fitkit/ dynamic fit (which ultimately left me injured).
My seat height is now 15mm lower than that method.

And how did Boresewicz allow for the rider to get used to any position while testing.
I am led to believe that you need 3 weeks or so to get used to a change of position.
I know when I first changed my setup I thought it was awful and that I had no power.
3 weeks later and all of that was forgotten.


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## cyclequip (Oct 20, 2004)

Fredrico said:


> Eddy Boresewicz (sp?), the guy who coached Alexi Grewal to Olympic victory in '84, wrote about tests conducted with pros. As saddles were raised, the legs could work as longer levers, taking advantage of a greater range of action of the muscles, thus more power and efficiency. This was up to about 96% of leg length. Above that, efficiency, power, dropped off precipitously. Below 96% the drop off curve was much shallower. Those experiments contributed to the LeMond formula mentioned here. I'd bet if you measured your positioning, your figures would come pretty close to the LeMond formula.


The seldom-mentioned anecdote to the tests EddieB carried out on those elite cyclists was that they ALL made the same power with their preferred saddle heights as they did with the "96%" formula.


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## Peanya (Jun 12, 2008)

It's funny that this thread came along, and at a good time for me. I had swapped saddles between bikes and the new one was shorter by about 1/2cm overall. I raised my saddle to compensate. The old saddle went on a new build, and I adjusted the position, but always got pain in the knees. So I went back to my other bike (the BMC), and the pain was still there!!!
After reading this article, I checked the position of the saddle, and I overcompensated. The saddle was too high! I had to lower it down by about 1cm, and the pain is gone now. 35 is definitely right for me.


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## wim (Feb 28, 2005)

Fredrico said:


> Cycling works the legs in circles, at more extreme angles than running or walking. The ligaments around the knees and butt (hips) stretch quite a bit more than when walking or running.


Actually, the exact opposite is true—especially so when looking at hip angles. The old (but still often-cited and unsurpassed) Cavanagh-Sanderson study on the biomechanics of elite riders lists hip -, knee - and ankle joint angles of elite pursuit riders at 100 rpm in a 53 x 13 gear combination. Interpreting the numbers, Cavanagh-Sanderson quickly come to the conclusion that there are few other sports where hip motion is as restricted as it is in cycling. For knee angles, they come to a similar conclusion.

For further reading and to study the actual numbers, look up Peter R. Cavanaugh, David J. Sanderson, _The Biomechanics of Cycling: Studies of the Pedaling Mechanics of Elite Pursuit Riders_, The Pennsylvania State University.


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## cda 455 (Aug 9, 2010)

FTR said:


> You need to be careful with "all the way back".
> My Sidi's are all the way back but when I did that on my Gaerne's I ended up with calf pain due to the fact that their is more rearward adjustability on the Gaerne's and as a result my "virtual saddle position" had changed.
> 
> Since using Steve's methods I have moved my cleats on both shoes by 10mm and have dropped my saddle height by 15mm.
> ...


What's interesting is, after I moved my cleats back, I noticed that (Since I'm a heel-dropper) the greater part of the width of my feet were actually/literally across the pedal axis. I can definitely feel more pressure in the front part of the foot arch than before.

Even riders who aren't heel-droppers find that when they're pedaling they're foot still rotates enough so that the ball of their foot is actually behind the pedal axis on traditionally placed cleats. My cleats go back only far enough to literally be properly placed (Greater part of the width of my foot over pedal axis). I wish I had about 1.5cm more of rearward adjust-ability.


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## Fredrico (Jun 15, 2002)

*You're right!*



wim said:


> Actually, the exact opposite is true—especially so when looking at hip angles. The old (but still often-cited and unsurpassed) Cavanagh-Sanderson study on the biomechanics of elite riders lists hip -, knee - and ankle joint angles of elite pursuit riders at 100 rpm in a 53 x 13 gear combination. Interpreting the numbers, Cavanagh-Sanderson quickly come to the conclusion that there are few other sports where hip motion is as restricted as it is in cycling. For knee angles, they come to a similar conclusion.
> 
> For further reading and to study the actual numbers, look up Peter R. Cavanaugh, David J. Sanderson, _The Biomechanics of Cycling: Studies of the Pedaling Mechanics of Elite Pursuit Riders_, The Pennsylvania State University.


What was i thinking?  Of course, a guy sitting on a saddle pumping the pedals with a 30 degree bend in his knees at the bottom of the pedal stroke, tightening up to 15(?) degrees at the top, isn't that much. And the femurs angling out of the hips, what, rotating back and forth about 15 or 20 degrees? "Ankling" is considered by some to be a myth. Most riders hold their ankles more or less in the same position relative to tibia through the whole pedal stroke, either toes down like Jacques Anquetil or "flat" like Eddy Merckx.

Come to think of it, stretching the legs before riding, after a hard effort while riding, and after riding, is beneficial to keep the muscles supple, as Hinault would say.

But what do I know? "Lower that saddle!" as the coach, name escapes me, said to most of his students at a race training seminar several years ago. :biggrin5:


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## Fredrico (Jun 15, 2002)

FTR said:


> It is *exactly *the height I used to ride based on BG/ fitkit/ dynamic fit (which ultimately left me injured).
> My seat height is now 15mm lower than that method.
> 
> And how did Boresewicz allow for the rider to get used to any position while testing.
> ...


Getting the legs used to working from a different saddle height of course takes time, 3 weeks, sure. That would explain the fact cyclequip relates, that elite riders tested by Eddy B delivered as much power from their old saddle positions as from the ones set at 96% of leg length (from the hips, not crotch). 

Commenting on your pain resulting from the Fit Kit, one can easily make mistakes measuring from crotch to floor in bare feet and end up with saddles that are too high. That's why setting height by the "rocking hips" method is more fool proof, IMO. What I was trying to relate about flexibility is, beginner riders have a hard time pedaling fast without rocking the hips, at any saddle height. So it would be logical to start out with lower saddles, less leg extension, to facilitate smooth pedaling at higher cadences. As the legs learn how to pedal fast without rocking the hips, then one could gradually raise the saddle for maximum leg extension (and thus power), to a point just below where the hips would start to rock as the legs were reaching to scribe the pedal through the bottom of the stroke. The higher the saddle, the longer the leg muscles must stretch. That can be an adaptive response to riding, within limits.


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## FTR (Sep 20, 2006)

Fredrico said:


> Getting the legs used to working from a different saddle height of course takes time, 3 weeks, sure. That would explain the fact cyclequip relates, that elite riders tested by Eddy B delivered as much power from their old saddle positions as from the ones set at 96% of leg length (from the hips, not crotch).
> 
> Commenting on your pain resulting from the Fit Kit, one can easily make mistakes measuring from crotch to floor in bare feet and end up with saddles that are too high. That's why setting height by the "rocking hips" method is more fool proof, IMO.


Frederico
I have a feeling that you and I are in "furious agreement" but are just coming to the same position from different angles.
Your hip rocking method and Steve's method probably come to a similar outcome but have been worded differently.
Have a read of his blog and see if you agree.


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## Fredrico (Jun 15, 2002)

FTR said:


> Frederico
> I have a feeling that you and I are in "furious agreement" but are just coming to the same position from different angles.
> Your hip rocking method and Steve's method probably come to a similar outcome but have been worded differently.
> Have a read of his blog and see if you agree.


Ok! :thumbsup: I'll do that!


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## Fredrico (Jun 15, 2002)

*Yeah!*



FTR said:


> Frederico
> I have a feeling that you and I are in "furious agreement" but are just coming to the same position from different angles.
> Your hip rocking method and Steve's method probably come to a similar outcome but have been worded differently.
> Have a read of his blog and see if you agree.


Interesting read, starting off with neurological determinants of efficiency and comfort, and also fitting asymmetrical organism to a symmetrical machine.

Steve says the saddle is too high if there's "accelerated velocity" at the back of the knee as the leg is cranking through the bottom of the pedal stroke with some force, like climbing. He recommends finding a nice long climb and lower the saddle until you feel a fluent through the bottom of the pedal stroke. If the saddle is too high, it will feel like "stepping" up the hill.

He also describes raising the saddle in 3 mm increments until one loses the sensation of fluency through the bottom of the stroke, then lowering it back to 3 mm below where that fluency was lost.

"Accelerated velocity," or "twitching" behind the knee is analogous to hips rocking, probably more precise, come to think of it.  But one would feel the hips rocking as well as stress on the back of the knees if the saddle were too high. When the saddle is at the right height, there would be a fluent stroke and the hips wouldn't rock. It would not only be possible to pedal strongly, but also to pedal fast, above 90 rpm, without losing this fluid pedal stroke. Also, if the hips are stable, the rest of the body could be relaxed and comfortable, not siphoning off energy used in the legs.

Once in a while we'll behold the beauty of that perfect form watching the pros. There's a reason those with the smoothest, most effortless looking form, are the ones who drop the others and come in first. .


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## cyclequip (Oct 20, 2004)

Fredrico said:


> Interesting read, starting off with neurological determinants of efficiency and comfort, and also fitting asymmetrical organism to a symmetrical machine.
> 
> Steve says the saddle is too high if there's "accelerated velocity" at the back of the knee as the leg is cranking through the bottom of the pedal stroke with some force, like climbing. He recommends finding a nice long climb and lower the saddle until you feel a fluent through the bottom of the pedal stroke. If the saddle is too high, it will feel like "stepping" up the hill.
> 
> ...


Fredrico, you are just about right, but I'd caution against the "hip rock" method of viewing and setting saddle height in favour of the "accelerated knee" method because hip rock can be caused by other fit factors apart from knee extension. Watching for the accelerated knee (or its close consort - the ankle-rise twitch) is a better way of setting that height as it does limit observation to resultants that are more consistent. So much pelvic stability stems from correct saddle width and shape that it can obscure height corrections.


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## wim (Feb 28, 2005)

Fredrico said:


> What was i thinking?  Of course, a guy sitting on a saddle pumping the pedals with a 30 degree bend in his knees at the bottom of the pedal stroke, tightening up to 15(?) degrees at the top, isn't that much.


A rider with a 30-degree knee angle bend at bottom dead center isn't going to "tighten up to 15 degrees at the top". The knee angle at top dead center is closer to 115 degrees, but perhaps you meant to write that. Range of motion of the knee joint would be 115 - 30 = 85 degrees, which isn't very much compared to many other sports. (These figures are based on the knee angle of a fully extended leg being 0 degrees.)

Not trying to be difficult here. Just want to make sure we're both talking about the same way of measuring knee joint angles.

.


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## Fredrico (Jun 15, 2002)

*Yes!*



wim said:


> A rider with a 30-degree knee angle bend at bottom dead center isn't going to "tighten up to 15 degrees at the top". The knee angle at top dead center is closer to 115 degrees, but perhaps you meant to write that. Range of motion of the knee joint would be 115 - 30 = 85 degrees, which isn't very much compared to many other sports. (These figures are based on the knee angle of a fully extended leg being 0 degrees.)
> 
> Not trying to be difficult here. Just want to make sure we're both talking about the same way of measuring knee joint angles.
> 
> .


I was looking at the back of the leg.  The angle at top stroke would be tighter than at bottom stroke, but nowhere near 15 or 30 degrees! 

But hey, 37 degrees! :shocked: Doesn't this guy's saddle look a bit high? The line of his back, noticed on the pattern on his jersey, changes when his other leg is on the down stroke. :idea: Over-extended?

Also, isn't he a bit stretched out? The line from his eyes to the front wheel hub falls behind the handlebars. Steve Hogg might have some questions for this guy. :ihih:


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## Fredrico (Jun 15, 2002)

cyclequip said:


> Fredrico, you are just about right, but I'd caution against the "hip rock" method of viewing and setting saddle height in favour of the "accelerated knee" method because hip rock can be caused by other fit factors apart from knee extension. Watching for the accelerated knee (or its close consort - the ankle-rise twitch) is a better way of setting that height as it does limit observation to resultants that are more consistent. So much pelvic stability stems from correct saddle width and shape that it can obscure height corrections.


Makes one appreciate the interplay of forces involved in riding. My "hips rocking" method assumes pedaling flat footed, preferably 95-100 rpm with feet attached to pedals, without movement in the ankles, and not moving on the saddle, difficult if not impossible to do without everything except saddle height dialed in perfectly!. 

Thanks for opening up some doors of perception. I'll check out Steve's blog again. The ergonomics of rider and bike have always fascinated me since I started riding, and I'm still learning! :thumbsup:


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## FTR (Sep 20, 2006)

Fredrico said:


> IAlso, isn't he a bit stretched out? The line from his eyes to the front wheel hub falls behind the handlebars. Steve Hogg might have some questions for this guy. :ihih:


Frederico
From all my reading the idea that hub should be obscured by the handlebar went out of fashion not long after the Ark was grounded on Mt Ararat.


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## Fredrico (Jun 15, 2002)

*Just funnin.*



FTR said:


> Frederico
> From all my reading the idea that hub should be obscured by the handlebar went out of fashion not long after the Ark was grounded on Mt Ararat.


This guy's arms come out of shoulders at more than a 45 degree angle! :shocked: He might look comfortable, but doesn't have that relaxed bend in his elbows.  I still think Steve H. would have questions for this guy!

(Where do you see the front hub when yer on the hoods? If I lean forward a little and stretch out my back, the hub disappears. :ihih: But I spend an awful lot of time on the tops. :idea


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## cda 455 (Aug 9, 2010)

FTR said:


> Frederico
> From all my reading the idea that hub should be obscured by the handlebar went out of fashion not long after the Ark was grounded on Mt Ararat.


Agreed.

I learned that shortly after I learned KOPS was old school/obsolete too.


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## FTR (Sep 20, 2006)

Fredrico said:


> This guy's arms come out of shoulders at more than a 45 degree angle! :shocked: He might look comfortable, but doesn't have that relaxed bend in his elbows.  I still think Steve H. would have questions for this guy!
> 
> (Where do you see the front hub when yer on the hoods? If I lean forward a little and stretch out my back, the hub disappears. ihih: But I spend an awful lot of time on the tops. :idea


Mine is hidden sometimes, in front sometimes and behind sometimes depending on how I am sitting.
It is not hidden because I purposely set my bike up that way though.


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## adam_mac84 (Sep 22, 2010)

you also realize that the error for goniometric measurements is at minimum +/- 3 degrees (even more in some studies, up to 8*)... so a measurement one day at 30* could really be 27-33... don't get too hung up on measurements.


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## wim (Feb 28, 2005)

adam_mac84 said:


> don't get too hung up on measurements.


+1 on that.

It's also interesting to note that if you establish saddle height with three popular methods (Hamley, Lemond and heel-on-pedal), knee angles can (but don't have to) vary considerably from cyclist to cyclist. Table 3 in the linked 2005 Peveler et al. saddle height study gives you the numbers. Not sure why that is so. (Peveler et al. call the heel-on-pedal method "Heal Toe" method in Table 3. But hey, no one is perfect).
http://www.asep.org/files/PevelerSaddle.pdf

.


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## GaRandonee (Dec 21, 2010)

From what I have read, start at around 30 and adjust as you see fit. When I was trying to adjust my current bike, I liked to make my assement after about 60km. That way I was somewhat fatigued, but I still had about 40km to decide if I would benefit by moving the saddle.  Don't forget about the for/aft adjustment. Also, I have never done it because I figure I would just second guess the results, but if you have the cash, a professional fit session might be an option.


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## shanabit (Jul 16, 2007)

Thanks guys.


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