Question About KOPS
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Question About KOPS
I'm 6' tall and measured my true inseam using the, "jam the book up against the crouch and measure to floor" at a length of 32". I bought a 56 cm Cannondale Caad8 Tiagra. I measured KOPS tonight and my knee was about 8 cm back from the middle of the pedal. I know KOPS isnt the be-all and end-all, but that seems pretty far back, when my seat is right in the middle of the rails.
Do I just have really short femurs or something? I know the reach to the handlebars is difficult, even with a 110mm stem.
Should I consider a zero setback seatpost?
Any help is appreciated
. Thanks in advance.
Do I just have really short femurs or something? I know the reach to the handlebars is difficult, even with a 110mm stem.
Should I consider a zero setback seatpost?
Any help is appreciated

Last edited by workingthrewit; 02-06-16 at 10:46 AM.
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Danger, Will Robinson, Danger!
It is always dangerous to give advice over the Internet on a topic like this which could result in long-term joint damage ... but it won't be my joints, so here goes.
Sounds like you have a long torso and short limbs. KOPS is a general and not a specific thing, but if "the reach to the handlrbars is difficult" well that is pretty specific isn't it? You could try a shorter or higher-angle stem, and I would definitely suggest trying the saddle more forward ... don't buy a new seatpost until you test that (would be my suggestion.)
A lot of people would suggest that you get a pro fitting ($50-$100) and there is a good calculator on the Competitive Cyclist site (Bike Fit Calculator | Find Your Bike Size | Competitive Cyclist) but pretty much if it feels wrong it is wrong.
I'd push the saddle as far forward as you need just to see how it feels. The you can decide whether to invest in a new seatpost, a shorter stem, neither or both. If the bike fits you should be able to ride comfortably for quit e along while. If you have to stretch and reach and bend painfully to ride the thing, it doesn't fit.
A lot of folks (like myself) have other-than-standard builds--I am your opposite, as I have limbs forever and my torso is about the size of a can of coke. People would suggest large or XL frames for me, but I can't reach the bars because my leg length pushes the seat back while my short torso negates the length of my arms. I have used the fit site I linked above, measured all my bikes, and even broke out the ruler and protractor and made a bunch of sketches to figure out what fits and what doesn't.
At most shops, I guess, they just look at your overall height and hand you whatever is in stock and reasonably close, and hustle you out the door (well, I guess you bought used ... buyer beware.)
The good news is, you ought to be able to make that bike fit you really well with the sort of stuff you have already been considering.
It is always dangerous to give advice over the Internet on a topic like this which could result in long-term joint damage ... but it won't be my joints, so here goes.
Sounds like you have a long torso and short limbs. KOPS is a general and not a specific thing, but if "the reach to the handlrbars is difficult" well that is pretty specific isn't it? You could try a shorter or higher-angle stem, and I would definitely suggest trying the saddle more forward ... don't buy a new seatpost until you test that (would be my suggestion.)
A lot of people would suggest that you get a pro fitting ($50-$100) and there is a good calculator on the Competitive Cyclist site (Bike Fit Calculator | Find Your Bike Size | Competitive Cyclist) but pretty much if it feels wrong it is wrong.
I'd push the saddle as far forward as you need just to see how it feels. The you can decide whether to invest in a new seatpost, a shorter stem, neither or both. If the bike fits you should be able to ride comfortably for quit e along while. If you have to stretch and reach and bend painfully to ride the thing, it doesn't fit.
A lot of folks (like myself) have other-than-standard builds--I am your opposite, as I have limbs forever and my torso is about the size of a can of coke. People would suggest large or XL frames for me, but I can't reach the bars because my leg length pushes the seat back while my short torso negates the length of my arms. I have used the fit site I linked above, measured all my bikes, and even broke out the ruler and protractor and made a bunch of sketches to figure out what fits and what doesn't.
At most shops, I guess, they just look at your overall height and hand you whatever is in stock and reasonably close, and hustle you out the door (well, I guess you bought used ... buyer beware.)
The good news is, you ought to be able to make that bike fit you really well with the sort of stuff you have already been considering.
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It would be hepful to see a picture of you on the bike.
KOPS is only a starting-point, but if your patella is 8cm behind the pedal and you are struggling with the reach, it's difficult to avoid the conclusion that bars and saddle are too far apart and that the main problem is the saddle position. So yes, I'd look at a zero setback seatpost and getting the saddle forward 50 or 60 mm and seeing how that feels. Remember that as you move the saddle forward you will also need to raise it, otherwise the distance from saddle to pedals will decrease.
KOPS is only a starting-point, but if your patella is 8cm behind the pedal and you are struggling with the reach, it's difficult to avoid the conclusion that bars and saddle are too far apart and that the main problem is the saddle position. So yes, I'd look at a zero setback seatpost and getting the saddle forward 50 or 60 mm and seeing how that feels. Remember that as you move the saddle forward you will also need to raise it, otherwise the distance from saddle to pedals will decrease.
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Saddle layback is governed by the proportion of upper to lower leg. I have no idea what is normal, but I seem to have long shanks and short femur, so I use an inline seatpost. In the olden days before seatpost varieties, I would have needed a custom seat-tube angle.
Crank length also impacts on layback.
Crank length also impacts on layback.
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A setback seatpost is what you'd want if you needed to get even further back. Moving the seat forward and getting a higher/shorter stem may be required for finding your optimal upper body position.
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Can an admin delete this post, as there is a duplicate?
I found the other one. For some reason, when I use the search function, search for my username, and use the default option of my recent posts, it doesn't show up. I found it another way, though.
I found the other one. For some reason, when I use the search function, search for my username, and use the default option of my recent posts, it doesn't show up. I found it another way, though.
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Have you tried a 54cm? I'm 5'-11" and ride a 54cm Cannondale Supersix EVO. I had a 54cm CAAD10 prior to the EVO.
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The Lord is merciful and gracious, slow to anger and abounding in steadfast love. - Psalm 103:8
I am a cyclist. I am not the fastest or the fittest. But I will get to where I'm going with a smile on my face.
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Thanks for the replies.
My greater focus is on endurance or higher mileage rides, as opposed to racing. Therefore, I was trying to avoid too great a drop from the saddle to the handlebars.
I figured since I have shorter legs, I would need a lower seatpost.
When reading the maxes on the saddle rails, is the max adjustment in relation to the top plate, or bottom plate that holds the saddle? If it's the bottom, this saddle only has about a couple mm or so on each side when the saddle is in the middle for adjustment.
I have tried a 54 cm frame, but the seatpost was pretty high, I must say.
My greater focus is on endurance or higher mileage rides, as opposed to racing. Therefore, I was trying to avoid too great a drop from the saddle to the handlebars.
I figured since I have shorter legs, I would need a lower seatpost.
When reading the maxes on the saddle rails, is the max adjustment in relation to the top plate, or bottom plate that holds the saddle? If it's the bottom, this saddle only has about a couple mm or so on each side when the saddle is in the middle for adjustment.
I have tried a 54 cm frame, but the seatpost was pretty high, I must say.
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Look for an endurance-style frame with a longer head tube, next time, like Giant Defy. For this bike, set up the saddle so that you are close to KOPS, and don't worry about the markings on the rails---it is just to get a few miles in and see if it works for you ... or just buy a 0-setback seatpost because you almost certainly need one.
If the CAAD8 frame has too short a head tube, you can get a higher-angle stem and a shorter one .... I use 80 mm on my Raleigh and it handles fine, looks good enough (not that I care about what others think since it is a bike to ride, not art to look at) and fits me really well. If you shop around you can find a stem and seatpost ---decent ones which don't weigh a ton---for $15-$25---Ebay/Amazon---also, if the steerer tube is long enough you can add spacers under the stem to raise it some.
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There is a Fitting your bike subforum. Have you asked there?
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32" is a pretty short bike inseam for a 6' individual. Something around 35-36" would be more typical. Measure in bare feet with book shoved up hard against the crotch and held against a wall to ensure the top is level.
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I have read of saddle rails getting bent because of adjusting it too far one way. Is that not true?
I did measure that way, Loo. I have a very long torso for my height. I stood up next to someone 4 inches shorter than me, and our legs started at just about the same spot. I have measured several times to be sure.
I know the Caad8 has a more heads up geometry than the Caad10. I thought it would be enough, but maybe not with my strange figure.
I will look at the bike fit calculator, as well.
I did measure that way, Loo. I have a very long torso for my height. I stood up next to someone 4 inches shorter than me, and our legs started at just about the same spot. I have measured several times to be sure.
I know the Caad8 has a more heads up geometry than the Caad10. I thought it would be enough, but maybe not with my strange figure.
I will look at the bike fit calculator, as well.
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If nothing else, sell the CAAD8 for what you paid and shop for something which fits better once you have better idea of what does fit better.
Say ... that CAAD8 ought to about fit me ...

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Thanks for the replies.
I have posted my measurements below. It is recommending a 58cm frame. I find that odd, as I was previously riding a 58cm frame, with the seat all the way forward, and the stock 120mm stem, and still was very stretched out.
If I'm stretched out on a 56cm frame, why would a 58cm frame be recommended?
Actual Inseam 32.25 In
Trunk 28.25 In
Forearm 14 In
Arm 28 In
Thigh 24.45 In
Lower Leg 22.50 In
Sternal Notch 59.50 In
Total Height 71.25 In
Top Tube Length 57.8 - 58.2 Cm
Seat Tube Range CC 54.2 - 54.7 Cm
Seat Tube Range CT 55.9 - 56.4 Cm
Stem Length 11.1 - 11.7 Cm
BB Saddle Position 72.8 - 74.8 Cm
Saddle Handlebar 57.9 - 58.5 Cm
Saddle Setback 5.5 - 5.9 Cm
Seatpost Type Setback
I have posted my measurements below. It is recommending a 58cm frame. I find that odd, as I was previously riding a 58cm frame, with the seat all the way forward, and the stock 120mm stem, and still was very stretched out.
If I'm stretched out on a 56cm frame, why would a 58cm frame be recommended?
Actual Inseam 32.25 In
Trunk 28.25 In
Forearm 14 In
Arm 28 In
Thigh 24.45 In
Lower Leg 22.50 In
Sternal Notch 59.50 In
Total Height 71.25 In
Top Tube Length 57.8 - 58.2 Cm
Seat Tube Range CC 54.2 - 54.7 Cm
Seat Tube Range CT 55.9 - 56.4 Cm
Stem Length 11.1 - 11.7 Cm
BB Saddle Position 72.8 - 74.8 Cm
Saddle Handlebar 57.9 - 58.5 Cm
Saddle Setback 5.5 - 5.9 Cm
Seatpost Type Setback