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  #1  
Old 01-13-2017, 09:51 AM
stephenmarklay stephenmarklay is offline
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Calling all bike fitters

Bloody Hell.

I don’t think I am that out for the ordinary but I am having issues.

First, I am just a shade under 6’0” with a 33.75” inseam.

I thought I was doing great. Comfy, feeling like I was powering with my glutes -all good.

Today I dropped plumb bob and found that my knee was way in front of the pedal axle as say Lemond would recommend. Doing some reading makes it sound like that is a good place to start.

I can only guess my femur is longer than normal. No clue really but to get my knee lined up with the pedal axle I am on a 25mm setback post, Brooks cambium slid all the way back on a 175mm crank on a 73 degree seat tube (I think that is what the CSI is) It just seems odd to me.

The plumb bob measurement is tricky too. I depends on the angle of the foot at 3 o'clock so I settled on flat.

Any help you can provide would be helpful.

Last edited by stephenmarklay; 01-13-2017 at 11:15 AM.
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  #2  
Old 01-13-2017, 10:19 AM
macaroon macaroon is offline
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Quote:
Originally Posted by stephenmarklay View Post
Bloody Hell.

I don’t think I am that out for the ordinary but I am having issues.

First, I am just a shade under 6’0” with a 33.75” inseam.

I thought I was doing great. Comfy, feeling like I was powering with my glutes -all good.

Today I dropped plumb bob and found that my need was way in front of the pedal axle as say Lemond would recommend. Doing some reading makes it sound like that is a good place to start.

I can only guess my femur is longer than normal. No clue really but to get my knee lined up with the pedal axle I am on a 25mm setback post, Brooks cambium slid all the way back on a 175mm crank on a 73 degree seat tube (I think that is what the CSI is) It just seems odd to me.

The plumb bob measurement is tricky too. I depends on the angle of the foot at 3 o'clock so I settled on flat.

Any help you can provide would be helpful.
The plumb bob measurement is not something you should bother with.
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  #3  
Old 01-13-2017, 12:08 PM
11.4 11.4 is offline
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How far forward? And are you having any knee problems? And are you happy with your power output? There are a lot of questions here. You know of course that that KOPS measurement is at best an indication and not a rigorous calculation, of course. If you have a short torso and long femurs, then yes, it's hard to fit a bike without your knees being forward of your pedals. The original point of that calculation was so you wouldn't have your knee flexed excessively while applying force to the pedal; it can hurt your knee and reduce power output in some cases, but to say the knee has to be arbitrarily over the pedal has no real substance. It's how a lot of people ride and how Italian pros were told to ride by CONI for thirty years. And they won a lot. So back to the questions. Provide more info and you have a chance of getting a useful response.
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Old 01-13-2017, 12:13 PM
stephenmarklay stephenmarklay is offline
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Thank you Macaroon.

I tend to agree at least in as much as they way i have been told.

The way I look at it is at 3 o’clock I want to be able to push down with as much force as possible. So where should my knee be relative to my foot.

I started thinking about TiDesigns who uses the sitting analogy to keep your weight distributed so not too much pressure is on the hands and that cycling is not like running and a light bulb went off.

At three o’clock my position is a lot (exactly) like my position as I stoop down ready to jump as high as I can. My butt goes out my torso goes down and I engage all of my musculature to shoot up. If I look in a mirror I look like I am on a bike seat and my glutes are firing hard and my weight is exactly distributed in a way to maximize force.

If I drop a plumb line down from that position my knee is lined up somewhere around my big toe. That makes as much sense as anything I can think of.
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  #5  
Old 01-13-2017, 12:58 PM
stephenmarklay stephenmarklay is offline
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Quote:
Originally Posted by 11.4 View Post
How far forward? And are you having any knee problems? And are you happy with your power output? There are a lot of questions here. You know of course that that KOPS measurement is at best an indication and not a rigorous calculation, of course. If you have a short torso and long femurs, then yes, it's hard to fit a bike without your knees being forward of your pedals. The original point of that calculation was so you wouldn't have your knee flexed excessively while applying force to the pedal; it can hurt your knee and reduce power output in some cases, but to say the knee has to be arbitrarily over the pedal has no real substance. It's how a lot of people ride and how Italian pros were told to ride by CONI for thirty years. And they won a lot. So back to the questions. Provide more info and you have a chance of getting a useful response.
Thanks 11.4.

My knee was about at the middle of my big toe and I was doing 10-15 minute 52 x 11 50 rpm hill climb grinds on the training practicing “falling on the pedals” with zero knee pain.

My power seems about the same with that position are rear of that.

As in the above post it seems like my jumping “ready stance” is about where I had my position on the bike. And this feels like a powerful way to be.

As an aside if I get in my jumping stance and try to bias my weight so that the plumb line is over the ball of my foot (where the cleat is at with regard to the axle) I will fall on my ass.

I think you hit the nail on the head. With my leg dimension relative to my torso my knee needs to be more forward.
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  #6  
Old 01-13-2017, 04:16 PM
nate2351 nate2351 is offline
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Don't trust a plumb lines dropped by yourself, there is way too much room for error.

That being said you also need to make sure that you're on a saddle that works for your body (not just comfort). When I set up on a saddle that's too wide, even by mms, a plumb line will always say I'm too far forward because I'm forward of the sit point on the saddle. Sliding the saddle back wont help this either because I'm just sliding on it.

Backing out a bit, KNOPS is great for finding "neutral" but I don't use it as fit dogma. Once you realize that all the fit points directly influence and are related to each other, then you can get great fits that disregard KNOPS. I very rarely set up folks at KNOPS.
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  #7  
Old 01-13-2017, 04:18 PM
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Ti Designs Ti Designs is offline
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Knee over pedal spindle is one of those measurements come up with to teach people who shouldn't be fitting how to fit. If you're looking to get your center of gravity over the pedal, and you have long femurs and a short torso, you should expect to have your knee past the pedal spindle. If that really bothers you, raise the front wheel a few inches and try again - then you can tell people your fit is optimized for climbing...

Seriously, if you can isolate the glutes and crank the biggest gear on the bike for 15 minutes, you probably already know more than the bike fitters who use KOPS just from personal experience.
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If the pedals are turning it's all good.
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  #8  
Old 01-13-2017, 07:32 PM
stephenmarklay stephenmarklay is offline
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Thanks you guys. In the morning I will put it back to whence it came.

I should have just been happy to feel good and be done but I had to go reading reminding myself of that plumb line stuff. That might work for some folks but it does not take sense to my for my fit.

I know the position that I am in to drop max weight and that is how I am setting my saddle.

I wonder if all those “he’s on the rivet comments” just means that guy should move his saddle forward
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  #9  
Old 01-14-2017, 11:52 AM
ultraman6970 ultraman6970 is offline
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Steven you have to account styles of riding too, some guys seat back of the saddle all the time, other ones seat in the tip of the saddle... etc etc. But if the nose of the saddle in your bike is like stupidly low and you sit in the tip, well that's like a problem.
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  #10  
Old 01-14-2017, 01:06 PM
macaroon macaroon is offline
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Some of the other more knowledgeable posters on this thread may be able to expand (or correct this!) But, I think the most powerful pedalling position is the one where you're sitting most comfortably and relaxed.

It has nothing to do with the position of your knees (or any other part of your leg) in relation to the pedal axle.

People like to use KOPS because in their heads, it makes sense: Knee directly over the pedal axle at the 3 o clock position must surely be the most powerful because it looks like it should be in terms of mechanics and diagrams.

But if that puts your upper body into a position where you can't get comfortable; where you're shuffling about and having to strain your core to remain balanced, then it's not a good position.

Quote:
Originally Posted by stephenmarklay View Post

I wonder if all those “he’s on the rivet comments” just means that guy should move his saddle forward
I think riding on the rivet is down to a number of things. I do it if I ride with my forearms on the tops for example. I think it's because:
I have to roll my pelvis further forward and my hamstrings aren't flexible enough, thus I shuffle forward on the saddle to lessen the reach my legs have to make to the pedals
Or, it's because of the "balance" thing I mentioned above, and my body has decided that's the best place it should be for that particular riding position. I can ride sat normally in my seat in that position, but not for long, I always end up back on the rivet.

Alberto Contador is a man that rides on the rivet; watch him when he's climbing. That's another thing to consider; riding uphill affects your balance/position on the bike (it effectively slackens the seat angle to start with). So shifting onto the rivet might help him to get over the top of the pedal stroke. I also think he probably sets his bike up a bit longer/lower than it should be, because he likes climbing out of the saddle. And IME, climbing out of the saddle is easier with a longer/lower bike.
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  #11  
Old 01-14-2017, 01:10 PM
macaroon macaroon is offline
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Something else to consider; perfecting your fit and pedalling technique on the trainer might not = a great fit and pedalling technique when you go outside on the road.

On a trainer you're locked in position and the feedback from the trainer is not the same as riding on the road IMO.
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  #12  
Old 01-14-2017, 07:02 PM
nate2351 nate2351 is offline
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It's important to set your bike up for what you're going to use it for. Your posture and the amount of body weight you carry on the saddle dramatically changes from 100 to 250 to 300 watts.

Having someone stop pedaling and dropping a plum line messes all of this up.
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  #13  
Old 01-15-2017, 05:47 PM
giordana93 giordana93 is offline
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pain free and feeling that power is good? write down your seat height and set back and put it in a safe deposit box. there are so many factors about seat set up that influence your variance away from a not so easily repeatable measurement of kops that you should absolutely disregard KOPS.
here is link to old bontrager article on the myth of kops

http://www.sheldonbrown.com/kops.html
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  #14  
Old 01-16-2017, 08:42 AM
benb benb is offline
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I've had a lot of trouble with this personally, I have a similar body size/shape..

In general if you let me just adjust the bike till I feel good my knee is going to be behind the pedal spindle. Just about any fitter I've worked with (quite a few, as I'm always having chronic bike fit issues it seems) will always try to push me forward to get my knee over the pedal spindle, regardless of how fancy their equipment is. Interestingly almost all of the places I've been fit almost all ignore the issues with whether the saddle position helps you unweight the handlebars or causes knee pain, it's all KOPS all the time. I think the knee thing is semi-forgivable though as in general fit sessions don't seem long enough to cause knee pain if the position is bad, you just don't seem to ride hard enough and long enough on their trainer/fit bike for stuff to begin hurting.

If I'm too far forward my knees will hurt. Exact same issue if I squat in one of those squat cages that has a bar that travels on a track, or if I'm not really careful with foot placement on a leg press machine. If your knees don't hurt then the position is probably fine for you. For me, I know I can't slide the saddle forward of KOPS, it will make my knees hurt unless there was perhaps something else going on like a very high saddle position or you shorten the cranks.

The saddle thing is very important too and all of this stuff interacts. If either the saddle or the position is not right my leg will push my sit bones around, particularly on my right leg, and I get saddle sores on the right side. For some reason this became a big big issue in the last year or so for me. The two most recent fits I had have seemingly made me way way more susceptible to that saddle sore, or saddles have changed or something has changed with my skin. (Saddles these days in general seem to have less padding and/or they've changed the way the edges of the saddle roll off.) My most recent fit when I put the bike on the trainer gave me a saddle sore in 15 minutes... horrible. All that moving of the sit bones and stuff is probably not helping my back, etc.. either.

BTW sliding the saddle too far back can impact your back too. Any change you make that is too extreme is going to have some negative impact somewhere else.

Last edited by benb; 01-16-2017 at 08:48 AM.
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  #15  
Old 01-16-2017, 07:42 PM
nate2351 nate2351 is offline
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Quote:
Originally Posted by benb View Post
The saddle thing is very important too and all of this stuff interacts. If either the saddle or the position is not right my leg will push my sit bones around, particularly on my right leg, and I get saddle sores on the right side. For some reason this became a big big issue in the last year or so for me. The two most recent fits I had have seemingly made me way way more susceptible to that saddle sore, or saddles have changed or something has changed with my skin. (Saddles these days in general seem to have less padding and/or they've changed the way the edges of the saddle roll off.) My most recent fit when I put the bike on the trainer gave me a saddle sore in 15 minutes... horrible. All that moving of the sit bones and stuff is probably not helping my back, etc.. either..
If your hips are moving around and causing friction on the sit bones then I'd drop the saddle. Honestly, to me this sounds like a saddle ~5mm too high. This is where things like Pubic Bone measurement or just looking a knee angle can be close bit yield a saddle height a bit off.
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