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Do you guys believe in the KOPS fit?

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Do you guys believe in the KOPS fit?

Old 10-14-05, 02:02 AM
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Sincitycycler
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KOPS: Knee-over -pedal-spindle.
-Greg Lemond was a big fan of this method of fore-aft method of measuring saddle position.
-Keith Bontrager is highly skeptical. http://www.sheldonbrown.com/kops.html
???
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Old 10-14-05, 02:24 AM
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Yes.
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Old 10-14-05, 03:05 AM
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It is a useful starting point if you are cluless.
It is only useful if you start out with the right size cranks.
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Old 10-14-05, 03:29 AM
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Yeah, it's a good starting point. My track-bike has its seat set about 1.5cm further forward than that and I like to slide back about 2.0cm on the road-bike when going up hills. So that's roughly a 5cm range that I will use.
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Old 10-14-05, 03:39 AM
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Yes.

For fun, over a couple of days we took six different cyclists and put them on the Cyclocomputer and did KOPS and looked at pedal stroke...then did several adjustments to look at whether power went up or down and how much of the stroke was actually used in comparison to KOPS.
KOPS won hands down.

Scientific? No, but it did help confirm what we believed.

There is a tendency for folks to buy aerobars and attach them to their road bikes and then make seat adjustments (instead of bar adjustments because they don't know any better) to "fit" for their more forward position...we definitely see that when they slide forward for the aero bars, they lose power and some of their pedal stroke. After adjusting, they get their power and stroke back.

What can we say? It's on the computer screen...

I am sure Bontrager thinks he is correct. We feel the evidence supports KOPS.

Last edited by roadwarrior; 10-14-05 at 04:44 AM.
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Old 10-14-05, 05:11 AM
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Originally Posted by roadwarrior
Yes.

There is a tendency for folks to buy aerobars and attach them to their road bikes and then make seat adjustments (instead of bar adjustments because they don't know any better) to "fit" for their more forward position...we definitely see that when they slide forward for the aero bars, they lose power and some of their pedal stroke. After adjusting, they get their power and stroke back.
Roadwarrior...are you saying that most run a too forward KOPS position when using clip on bars...by running their seat more forward? How should this be remedied?...a shorter stem?...sliding the aerobars/pads rearward and maintain saddle position? Are you saying that a 2-3cm KOPS forward position is not preferred for TT's?
George
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Old 10-14-05, 05:24 AM
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My personal experience is that KOPS has worked for me after I got my crank length right. When I was using cranks that were too long KOPS just added an error on top of another error.

My understanding is that Triathletes deliberately move there riding position forward not because it's efficient but because by doing so they are cycling with different muscles than they will use when running. If your exclusively cycling and doing a TT then a good Triatholon position isn't realy a good TT position.

With cycling you obviously want to efficiently use ALL your muscles.

Regards, Anthony
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Old 10-14-05, 05:49 AM
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Originally Posted by biker7
Roadwarrior...are you saying that most run a too forward KOPS position when using clip on bars...by running their seat more forward? How should this be remedied?...a shorter stem?...sliding the aerobars/pads rearward and maintain saddle position? Are you saying that a 2-3cm KOPS forward position is not preferred for TT's?
George
What happens is that the rider ends up moving the seat forward to get closer to the aero bars, but obviously their feet stay in the same place. If they switch back to the drop bars, some of them change position (now they are too close). If that makes sense. What we are trying to do is get the bars set up so that they can ride in either position with the KOPS setup...
I saw a guy, yesterday, who had aero bars and he looked ike he was laying on his stomach his feet were so far behind him. We can set up the bike on the computer, look at the pedal stroke in both positions (aero and drop), then adjust, and do it again. And show the rider how they have increased power AND speed.
The bars adjust (unless they are real cheapies, but those folks are not dropping over a hundred dollars for a 2-3 hour fitting, either). If it's on a road bike (which is more prevalent than a TT bike which has a different geometry), ultimately trying to get the rider where they are able to ride on either bar from the same sitting position is the goal..
I think I answered your question...
Most folk's bikes we see are not set up that way...not even close.

Some riders are unique and some have personal tastes due to lengthy extensive racing experience. But the average (I'm thinking about doing tri's and TT's) rider we try to set up pretty neutral...having that pedal setup with the computer sensor really shows us the optimal pedaling efficiency for each rider.

Last, I don't want to leave with "one size fits all" as it does not. That's the beauty of looking at the power and stroke efficiency.
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Old 10-14-05, 06:04 AM
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Originally Posted by roadwarrior
What happens is that the rider ends up moving the seat forward to get closer to the aero bars, but obviously their feet stay in the same place. If they switch back to the drop bars, some of them change position (now they are too close). If that makes sense. What we are trying to do is get the bars set up so that they can ride in either position with the KOPS setup...
I saw a guy, yesterday, who had aero bars and he looked ike he was laying on his stomach his feet were so far behind him. We can set up the bike on the computer, look at the pedal stroke in both positions (aero and drop), then adjust, and do it again. And show the rider how they have increased power AND speed.
The bars adjust (unless they are real cheapies, but those folks are not dropping over a hundred dollars for a 2-3 hour fitting, either). If it's on a road bike (which is more prevalent than a TT bike which has a different geometry), ultimately trying to get the rider where they are able to ride on either bar from the same sitting position is the goal..
I think I answered your question...
Most folk's bikes we see are not set up that way...not even close.

Some riders are unique and some have personal tastes due to lengthy extensive racing experience. But the average (I'm thinking about doing tri's and TT's) rider we try to set up pretty neutral...having that pedal setup with the computer sensor really shows us the optimal pedaling efficiency for each rider.

Last, I don't want to leave with "one size fits all" as it does not. That's the beauty of looking at the power and stroke efficiency.
Great insight thank you....seems like it would be difficult to serve both masters...achieving KOPS in drops and in aerobar position and I guess a TT bike is irrelevant as they have integrated aerobars. A last question please...for a fitness cyclist...not a racer...do you believe a good set of clip on bars is a benefit?...not necessarily in speed though that maybe added benefit...but reduction in long term upper body fatigue by offering another riding position that may offer better upper body support for longer training rides?
Thanks again,
George
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Old 10-14-05, 06:31 AM
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Originally Posted by biker7
Great insight thank you....seems like it would be difficult to serve both masters...achieving KOPS in drops and in aerobar position and I guess a TT bike is irrelevant as they have integrated aerobars. A last question please...for a fitness cyclist...not a racer...do you believe a good set of clip on bars is a benefit?...not necessarily in speed though that maybe added benefit...but reduction in long term upper body fatigue by offering another riding position that may offer better upper body support for longer training rides?
Thanks again,
George
Sure...lot's of riders who are in it for fitness have clip on bars...it allows them to rest more of their upper body weight on a bigger contact point which many find comfortable. You hold yourself up a bit less with the abdominal muscles, resting your torso on your forearms.
The deal is that most get their bars, put them on themselves and do not even know that they are adjustable. So they adjust the seat. Adjust the bars for the riding position, do not adjust the riding position for the bars....ultimately, that's my point.
TT bikes have a different geometry. They are designed for aero tuck riding.

Here's some more info...

We are attempting to get the same torso/femur angles by adjusting the bars properly (you can't ride a bike very well by hitting your thighs into your chest). You will not be in as optimal a position aerodynamically (that's why they make TT bikes), but you can be comfortable and able to breathe.

Last edited by roadwarrior; 10-14-05 at 06:44 AM.
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Old 10-14-05, 09:14 AM
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I think the best thing that Bonty's article does is show that KOPS isn't the gospel truth that many believe it to be. It's not a one size fits all solution to positioning your saddle fore/aft. But, it's a great place to start and adjust from. From my experience, though, any rule of thumb in bike fit has the potential to, when applied, work against the rider. That's why they're rules of thumb, though.

I wish Bontrager's article still had the equations to determing CG, etc. I'd like to see how different my position would be in relation to KOPS, if at all. Either way, his article does bring up some very good points about weight balance on the bike if nothing else.
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Old 10-14-05, 09:39 AM
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The whole problem with the world of bike fitting is that what works well for one person may not work as well for another. I think taking bike fitting input from a fitter is fine but fitting has to be a personal thing. Fitters don't have to ride the bike after it is fit. You do. It needs to be comfortable or efficient or both for you, not for the average person and not for the fitter. So I think you can take fitting advice as input but don't fall into the trap of considering it gospel. Use things like KOPS or what bike fitters do as a starting point. These things will normally get you pretty close to being fit. The rest is up to you.
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Old 10-14-05, 09:44 AM
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^^ I agree 100%

I am one of the lucky ones because KOPS always works for me.
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Old 10-14-05, 10:08 AM
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I find it as a good baseline. I've found over time, I like more setback.
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Old 10-14-05, 10:09 AM
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I think we need more people to say the exact same thing using different words.
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Old 10-14-05, 10:17 AM
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Consider - I started having some knee problems lately and noted that my various saddle changes had put me pretty far behind KOPS. I moved the saddle forward and the knee problems faded away in a couple of days.
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Old 10-14-05, 10:23 AM
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Originally Posted by roadwarrior
Sure...lot's of riders who are in it for fitness have clip on bars...it allows them to rest more of their upper body weight on a bigger contact point which many find comfortable. You hold yourself up a bit less with the abdominal muscles, resting your torso on your forearms.
The deal is that most get their bars, put them on themselves and do not even know that they are adjustable. So they adjust the seat. Adjust the bars for the riding position, do not adjust the riding position for the bars....ultimately, that's my point.
TT bikes have a different geometry. They are designed for aero tuck riding.

Here's some more info...

We are attempting to get the same torso/femur angles by adjusting the bars properly (you can't ride a bike very well by hitting your thighs into your chest). You will not be in as optimal a position aerodynamically (that's why they make TT bikes), but you can be comfortable and able to breathe.
Thank you brother...I appreciate your advice,
George
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Old 10-14-05, 10:58 AM
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Originally Posted by roadwarrior
Yes.

For fun, over a couple of days we took six different cyclists and put them on the Cyclocomputer and did KOPS and looked at pedal stroke...then did several adjustments to look at whether power went up or down and how much of the stroke was actually used in comparison to KOPS.
KOPS won hands down.

Scientific? No, but it did help confirm what we believed.
I'd be curious as to how the "powerful" (i.e. KOP) position in your study felt. IMO, for an individual some positions feel stronger than others, but are they?

For reasons I won't go into, I've been chasing the right setup on one of my bikes for over a month. My criteria is it has to be comfortable, I have to be able to get power on climbs and flats, spinning or mashing. My feet and the pedals have to feel like they "agree" throughout the stroke. Weight has to be positioned such that the bike handles well. And it has to feel good for several rides, to ensure it doesn't feel good just because it's using fresher muscles, etc. I'm pretty close to it now... we're definitely talking about very tiny adjustments. (I'll check KOP, just out of curiosity. I think it's close, maybe a little behind the axle.) What I'm really curious about is that now that I have my setup dialed in, how power output varies, and if what feels comfortable and strong, really is the sweet spot in terms of performance.

Thoughts, anyone?
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Old 10-14-05, 12:46 PM
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Originally Posted by roadwarrior
...There is a tendency for folks to buy aerobars and attach them to their road bikes and then make seat adjustments (instead of bar adjustments because they don't know any better) to "fit" for their more forward position...we definitely see that when they slide forward for the aero bars, they lose power and some of their pedal stroke. After adjusting, they get their power and stroke back.

What can we say? It's on the computer screen...

I am sure Bontrager thinks he is correct. We feel the evidence supports KOPS.
Do you have the force-profile vs. crank-position per revolution on that for the various positions? Or just total power-output? The top triathletes seem to be very, very similar to cyclists with a more rearward position. I suspect the more forward position ends up giving higher peak-forces during the downstroke and is easier for people who aren't spinners. It makes them feel like they're able to "push" harder through a narrow portion of the crank-revolution, but they end up sacrificing a larger portion. So it decreases total power-output per revolution because the average force is lower overall.

So yes, I agree with you, keep the most efficient position and adjust the bars or build a bike to fit your body's most efficient configuration. Although I suspect a lot of people also don't have the upper body-strength to support an semi-Superman position with arms extended forward as well, a lot of them like to have their upper-arms vertical to support their upper bodies without any shoulder muscles needed. I wonder if anyone has any wind-tunnel data compared to this (looks like knee is ever so slightly behind pedal spindle):


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Old 10-14-05, 12:55 PM
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Originally Posted by roadbuzz
I'd be curious as to how the "powerful" (i.e. KOP) position in your study felt. IMO, for an individual some positions feel stronger than others, but are they?

For reasons I won't go into, I've been chasing the right setup on one of my bikes for over a month. My criteria is it has to be comfortable, I have to be able to get power on climbs and flats, spinning or mashing. My feet and the pedals have to feel like they "agree" throughout the stroke. Weight has to be positioned such that the bike handles well. And it has to feel good for several rides, to ensure it doesn't feel good just because it's using fresher muscles, etc. I'm pretty close to it now... we're definitely talking about very tiny adjustments. (I'll check KOP, just out of curiosity. I think it's close, maybe a little behind the axle.) What I'm really curious about is that now that I have my setup dialed in, how power output varies, and if what feels comfortable and strong, really is the sweet spot in terms of performance.

Thoughts, anyone?
I actually think that perceived output can be misleading. If someone makes a change to their position on the bike and is asked after the first ride post-change "what'd you think?" they might very well say that they felt that it wasn't as powerful for them. The method of measuring actual output is less subjective. I'd love to hook up a power meter on my bike and compare one ride's data to another's while keeping all but the bike position as close to constant as I can.
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Old 10-14-05, 02:11 PM
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I thought the TT position necessarily brought the knee forward because the whole position is rotated around the BB.

If you just dropped the bars and maintained the KOPS position, wouldn't you severely constrain the hip angle?
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Old 10-14-05, 02:11 PM
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Also remember that Lemond ran a slacker seattube due to his longer femur. KOPS, as has been said is just a starting point, just as the bar over the hub sightline. As time goes on, you tend to have more setback and more extension on the stem.
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Old 10-14-05, 04:30 PM
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Originally Posted by ImprezaDrvr
I think we need more people to say the exact same thing using different words.
That which is required is an increased number of the population expressing their cohesive views by way of varied verbalism.
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Old 10-14-05, 07:03 PM
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Originally Posted by The Carpenter
That which is required is an increased number of the population expressing their cohesive views by way of varied verbalism.
+1
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Old 10-15-05, 11:25 AM
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Originally Posted by ImprezaDrvr
I think we need more people to say the exact same thing using different words.
It's easy to all chime in when we have varying opinions. But if we all believe "It's just a guideline", how else can we all chime in? So here's my take:

I don't know what to think of KOPS. I'm too new at this. Maybe it works, maybe it doesn't. I hope that clears things up a bit. =)
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