Results 1 to 24 of 24
  1. #1
    mtbr member
    Reputation: Ottoreni's Avatar
    Join Date
    Jan 2004
    Posts
    1,013

    Saddle Fore Aft Position for long rides ....

    I have been doing lot longer rides lately and in the process playing with my saddle fore aft position as it relates to my bottom bracket .....

    I originally had the tip of my saddle about 62mm behind the mounting bolt of my bottom bracket. Recently, I moved it up to about 52mm and swapped out the stem for one that is 10mm longer. Big difference! A whole different set of muscles feel fatigued.

    I can achieve KOPS in both positions. In one KOPS set-up, saddle farther back, my extended leg is in more of a diagonal line in relation to the bottom bracket versus with the saddle forward, my leg is more vertical in relation to the bottom bracket and the saddle is slightly higher.

    My question is how far back is your saddle tip in relation to your bottom bracket center?

    AND

    Is one set-up better than the other?

    How I measured:
    I measured my bike by placing the rear wheel perpendicular against the wall. Then I measured the distance form the wall to the bottom bracket center. Next, I measured the distance from the wall to the saddle tip. The last step was to subtract the two measurements.
    You cannot go against nature, because when you do, its part of nature too.

  2. #2
    mtbr member
    Reputation: mudge's Avatar
    Join Date
    May 2010
    Posts
    1,127
    Not sure how you're measuring KOPS, but if your pedal is in the 3:00 position (where it's supposed to be), there's only one saddle position that will achieve KOPS (assuming you're sitting on the saddle in the same spot each time and you aren't monkeying around with your cleats).

    edit: after reading Tom's response, it occurred to me I forgot the additional caveat that your saddle height is proper, too. You could, conceivably, put your knee directly over the spindle at the 3 o'clock position and slide your saddle back and forth quite a bit, if you change the saddle height as well.

    As has been mentioned, it's almost impossible to measure your position by yourself. The plumb line just won't cooperate and it's more likely than not you won't have it fixed to the correct spot on your knee in the first place.
    Last edited by mudge; 04-08-2013 at 06:45 PM.

  3. #3
    Team Velveeta™
    Reputation: TomP's Avatar
    Join Date
    Jan 2004
    Posts
    2,226
    Quote Originally Posted by mudge View Post
    Not sure how you're measuring KOPS, but if your pedal is in the 3:00 position (where it's supposed to be), there's only one saddle position that will achieve KOPS (assuming you're sitting on the saddle in the same spot each time and you aren't monkeying around with your cleats).
    My first reaction to this was exactly the same as yours. I think there may be one caveat, KOPS changes in a subtle way with variations in saddle height. HOWEVER, there is an optimum saddle height. If you slide the saddle back or forward, ultimately the distance from crank center to where you should be sitting on the saddle changes. Forward effectively lowers the saddle, back effectively raises it. So when you're trying to achieve KOPS as you also get optimum saddle height established, there's a tweak tweak tweak process that happens. Set saddle height, measure KOPS, adjust saddle position fore/aft if necessary, adjust saddle height to compensate for change in fore/aft position--lather, rinse, repeat. At a point you will get to optimum combination of saddle height and fore/aft position.

    Then as mudge points out--if you decide to tweak cleat position, the process starts all over.

    FURTHERMORE, some people pedal toes-down. If you watch someone pedal from the side, sometimes the foot is roughly horizontal, but often it's pointing down and forward. This is especially true of riders who aren't very flexible (me!). That effects optimum saddle height, and by association it effects KOPS. Some of us then become either more or less flexible as we get fit. So everything should be tweaked again to maintain optimum.

    And further to that point, you can't reliably measure KOPS yourself. You need an assistant. And it should all be done in a situation where you can for example sit on a trainer and pedal for a while until your circle becomes regular and foot position finds it's norm. Then you should stop pedaling and not adjust your foot angle. Take a measurement.

    There are strong and quite possibly valid arguments that this much focus is anal-retentive overkill. But I would suggest that anybody who cares about optimum power and maximizing comfort on the bike should get a professional fit. I have worked at a shop that has an excellent fit staff. Constant retraining with the Specialized BG fit program. One of the fitters is one of the only BG Fit instructors in the country who works at a shop. I've been lucky to be able to get free fits 3 or 4 times. I have after each one, performed minor (2-3mm) tweaks on my saddle fore-aft. Fits always seem to have my saddle just a hair further back than I want. After all this time riding bikes where leg extension and KOPS have been meticulously set, I can feel where it needs to be. Princess and the Pea sensitivity. That's worth getting, at least once.

    To the OP, I applaud your efforts to figure this stuff out. I believe that it's totally beneficial. But if it's important to you, I'd recommend getting some help, establishing a baseline pro fit, writing down the results and then using that as a starting point whenever you look at the way a bike is fitting you. Not that you should have to duplicate the fit to the millimeter, but that you know what the baseline looks like.

    My $.02
    Tom Purvis - Salida, CO - http://teamvelveeta.tom-purvis.com

    "I like my wimmen like I like my beer--cold and bitter!"

  4. #4
    mtbr member
    Reputation:
    Join Date
    Aug 2007
    Posts
    451
    I agree with what Tom said.

    Get a professional bike fit from a highly regarded fitter, and while you are doing it ask questions. Once you have the fit completed, measure and record all the key elements of the fit. Put that measurement somewhere safe, so you can come back to it as a baseline. You will need that baseline in the future as more often than not an athlete will play around with the setup, until it is nothing like the baseline. It's best if you can always go back to 'a last known good', once things get out of control.

    Finally, no matter what changes you are making, allow a week or two for them to settle in to your riding style and assess at that point, make changes as necessary, wait a couple of weeks, assess, repeat.

    It's worth spending the time to get a dialled in fit, especially if you are doing long endurance races. Good luck with it.

  5. #5
    mtbr member
    Reputation: Ottoreni's Avatar
    Join Date
    Jan 2004
    Posts
    1,013
    First off, thanks for the responses.

    As for a fitting, I wish I could do this, but I have the misfortune of living in S. Florida and loving dirt riding. We have pretty nice trails here, but the majority of the LBS are nothing to write home. I can list a multitude of mishaps I have had with local shops. My one local shop that I enjoy going to has the local "fit guru", but I am totally unimpressed by him. He is the guy who trued my wheel perfectly, but it was dished to the drive-side completely. The same guy who will willingly use a metric or standard allen wrench without regard to what really needs to be used. For this reason, I am not too confident in his abilities. I am anal about my bike. I am a constant tinkerer .... much to my demise.

    I don't know of any other local fitters that I would trust ..... and I don't want to spend north of $200 for a fit that I think will be sub-par.

    As for the KOPS deal, I will do my best to set this up again. I will try again....my wife rolls her eyes when I approach her with the plumb line

    Thanks for the responses ... and I will continue tinkering....
    You cannot go against nature, because when you do, its part of nature too.

  6. #6
    Team Velveeta™
    Reputation: TomP's Avatar
    Join Date
    Jan 2004
    Posts
    2,226
    Quote Originally Posted by Ottoreni View Post
    First off, thanks for the responses.

    As for a fitting, I wish I could do this, but I have the misfortune of living in S. Florida and loving dirt riding. We have pretty nice trails here, but the majority of the LBS are nothing to write home. I can list a multitude of mishaps I have had with local shops. My one local shop that I enjoy going to has the local "fit guru", but I am totally unimpressed by him. He is the guy who trued my wheel perfectly, but it was dished to the drive-side completely. The same guy who will willingly use a metric or standard allen wrench without regard to what really needs to be used. For this reason, I am not too confident in his abilities. I am anal about my bike. I am a constant tinkerer .... much to my demise.

    I don't know of any other local fitters that I would trust ..... and I don't want to spend north of $200 for a fit that I think will be sub-par.

    As for the KOPS deal, I will do my best to set this up again. I will try again....my wife rolls her eyes when I approach her with the plumb line

    Thanks for the responses ... and I will continue tinkering....
    Wow, South Florida. My condolences Seriously, my sister and her husband live down there. I couldn't last two weeks living there.

    I wouldn't recommend laying down the coin for something you weren't confident in. Wouldn't do it either.

    One tip, if you can get your hands on a carpenter's laser level they are way nicer to work with than a plumb bob. Wives and their rolling eyes, you have my sympathy on that too
    Tom Purvis - Salida, CO - http://teamvelveeta.tom-purvis.com

    "I like my wimmen like I like my beer--cold and bitter!"

  7. #7
    mtbr member
    Reputation:
    Join Date
    Oct 2004
    Posts
    4,353
    Well, I'll throw out a simple answer: For endurance racing and really long rides in general, I prefer my saddle about 5-7 mm forward of the classic KOPS position.

    FWIW, my legs are kind of short in relation to my torso and total height.
    The drive towards achievement and success is the motive power of civilization.

  8. #8
    mtbr member
    Reputation: mudge's Avatar
    Join Date
    May 2010
    Posts
    1,127
    Quote Originally Posted by kosmo View Post
    Well, I'll throw out a simple answer: For endurance racing and really long rides in general, I prefer my saddle about 5-7 mm forward of the classic KOPS position.

    FWIW, my legs are kind of short in relation to my torso and total height.
    That's interesting. I wonder, is it because of how your legs feel or does being slightly forward help with your lower back?

  9. #9
    mtbr member
    Reputation:
    Join Date
    Oct 2004
    Posts
    4,353
    Quote Originally Posted by mudge View Post
    That's interesting. I wonder, is it because of how your legs feel or does being slightly forward help with your lower back?
    Not exactly sure, but in general, the slight forward position gives me a feeling of smooth power, while the classic position has a tiny hint of the need to "shove" forward with my legs.

    And by the luck of the draw, I'm generally blessed with a happy back, although I try to fit in a sort of rigorous core/back workout twice a week, which might help in that regard.
    The drive towards achievement and success is the motive power of civilization.

  10. #10
    Team Velveeta™
    Reputation: TomP's Avatar
    Join Date
    Jan 2004
    Posts
    2,226
    Quote Originally Posted by kosmo View Post
    Well, I'll throw out a simple answer: For endurance racing and really long rides in general, I prefer my saddle about 5-7 mm forward of the classic KOPS position.

    FWIW, my legs are kind of short in relation to my torso and total height.
    After writing War & Peace on the subject of the benefit of pro fitting and optimum saddle height/setback, I'll say that I have a similar bias. I have had KOPS dialed exactly on three or four different bikes and then almost immediately moved my saddle forward a bit. My guess would be in the 5mm range or less, but KOPS feels like a bit of a strain for some reason.

    I actually have long femurs relative to my leg length, but I also have little or no ACL. Worse on the right which is my stronger leg. Turned that foot around backwards at Mary Jane over twenty years ago. Pop!

    It also occurs to me that I have noticed the intolerance for precise KOPS just as the climb started. When the whole bike cants back, KOPS kind of changes, don't you think?
    Tom Purvis - Salida, CO - http://teamvelveeta.tom-purvis.com

    "I like my wimmen like I like my beer--cold and bitter!"

  11. #11
    mtbr member
    Reputation:
    Join Date
    Jan 2008
    Posts
    571
    I'd always understood that KOPS is a rough tool meant to get people close to a reasonable fit. Most peeps I know (who are actually aware of their measurements) sit a bit forward of the spindle.

    These people also tend to ride shorter events and I don't know enough about bio-mechanics to know if the quad is more engaged (alternatively if the hammy is less engaged) the more forward you are. I suspect that's the case as most of my tri-dork friends sit pretty far forward to "save their legs" for the run.

  12. #12
    mtbr member
    Reputation:
    Join Date
    Oct 2004
    Posts
    4,353
    Quote Originally Posted by TomP View Post
    It also occurs to me that I have noticed the intolerance for precise KOPS just as the climb started. When the whole bike cants back, KOPS kind of changes, don't you think?
    I think you're on to something there. It is definitely the steeper climbs where perfect KOPS feels strained to me.

    And in the races I participate in (Butte 100, Creampuff, Capitol Forest), there is little are little or no flat work involved. You're either going up or down.
    The drive towards achievement and success is the motive power of civilization.

  13. #13
    mtbr member
    Reputation: santabooze's Avatar
    Join Date
    Oct 2010
    Posts
    156
    Quote Originally Posted by staylor View Post
    I agree with what Tom said.

    Get a professional bike fit from a highly regarded fitter, and while you are doing it ask questions. Once you have the fit completed, measure and record all the key elements of the fit. Put that measurement somewhere safe, so you can come back to it as a baseline. You will need that baseline in the future as more often than not an athlete will play around with the setup, until it is nothing like the baseline. It's best if you can always go back to 'a last known good', once things get out of control.

    Finally, no matter what changes you are making, allow a week or two for them to settle in to your riding style and assess at that point, make changes as necessary, wait a couple of weeks, assess, repeat.

    It's worth spending the time to get a dialled in fit, especially if you are doing long endurance races. Good luck with it.
    And I agree with what Staylor say's
    I had a pro fit last year, and so far the only setting that has remained is my saddle fore/aft position. All other setting have changed. ( by small increments of course)

    Recently, I had my bars removed from my stem without my knowledge. When I was resetting this it was nice to go back to my saved settings in my documents,and find my original position for bar/grip/shifter angle. I was then able to dial in my personal fit very quickly.

  14. #14
    mtbr member
    Reputation:
    Join Date
    Aug 2010
    Posts
    1,380
    Quote Originally Posted by Walt Disney's Frozen Head View Post
    I'd always understood that KOPS is a rough tool meant to get people close to a reasonable fit. Most peeps I know (who are actually aware of their measurements) sit a bit forward of the spindle.

    These people also tend to ride shorter events and I don't know enough about bio-mechanics to know if the quad is more engaged (alternatively if the hammy is less engaged) the more forward you are. I suspect that's the case as most of my tri-dork friends sit pretty far forward to "save their legs" for the run.
    The triathletes are in a very forward and low aero position, so they need to be further forward over the cranks to keep the hip angle reasonable. Likewise, on a mtb if you have a more upright position it would make sense to have a more rearward seat position compared to someone who has a more horizontal torso position.

    I'm a little surprised that so many folks here like their saddle a bit forward of the KOPS position. The more forward position uses the quads more, which can feel like it's stronger, but moving the saddle aft uses more of the posterior muscles (hamstrings, glutes, lower back), which are actually more powerful.

    I'm still sorting out my position. As an ex-triathlete I felt like the KOPS position or slightly forward was good, but lately I've been moving my saddle back behind this position and I feel like it might provide more power plus provide better balance going over obstacles and through rock gardens.

  15. #15
    mtbr member
    Reputation:
    Join Date
    Jul 2006
    Posts
    733
    I prefer my saddle just a bit back of KOPS, I feel more engaged in my glutes and hamstrings. Personal preference, I guess. I do move towards the nose of my saddle on steeper climbs, though, to kinda keep my position relative to the pedals. When I had a more KOPS position, I found I got hip flexor and quad cramps.

  16. #16
    Nouveau Retrogrouch SuperModerator
    Reputation: shiggy's Avatar
    Join Date
    Dec 1998
    Posts
    48,052

    Saddle Fore Aft Position for long rides ....

    Quote Originally Posted by kosmo View Post
    I think you're on to something there. It is definitely the steeper climbs where perfect KOPS feels strained to me.

    And in the races I participate in (Butte 100, Creampuff, Capitol Forest), there is little are little or no flat work involved. You're either going up or down.
    Note that TomP is wearing his CCP finisher cap in his avatar.
    mtbtires.com
    The trouble with common sense is it is no longer common

  17. #17
    Team Velveeta™
    Reputation: TomP's Avatar
    Join Date
    Jan 2004
    Posts
    2,226
    Quote Originally Posted by shiggy View Post
    Note that TomP is wearing his CCP finisher cap in his avatar.
    That hat is one of my prized possessions. I only wear it on special occasions.

    CCP was a great experience. But next time I'm in Oak Ridge/Westfir I'm just going to ride and explore. I wasn't around for NEARLY long enough in '08 when I did the race. The only singletrack I saw was on the racecourse. One pre-ride (with Mtbr member jms) and then race day. I was working at a bike shop that summer and it was hard to get enough time to really do it during the high season at the beginning of summer. Four days of driving from central CO, three days in Westfir. Not enough time!
    Tom Purvis - Salida, CO - http://teamvelveeta.tom-purvis.com

    "I like my wimmen like I like my beer--cold and bitter!"

  18. #18
    jms
    jms is offline
    mtbr member
    Reputation: jms's Avatar
    Join Date
    Feb 2006
    Posts
    2,583
    Quote Originally Posted by TomP View Post
    The only singletrack I saw was on the racecourse. One pre-ride (with Mtbr member jms) and then race day.
    No one I'd rather get lost on a pre ride with than you Tom : )
    My Favorite Peeps:

  19. #19
    Fat-tired Roadie
    Reputation: AndrwSwitch's Avatar
    Join Date
    Nov 2007
    Posts
    13,751
    I really like the discussion of saddle fore/aft position in Peter White's article on fit. I really like the whole article, but the thread's about fore/aft position.

    There are two tendencies stronger cyclists have. One is to develop more power, and another is to ride with a lower torso, to help keep things in balance. The adjustments related to these changes, if we come up with some other-things-equal baseline cyclist who's now getting stronger, contradict each other. Move the saddle forward because of more power and back because of a lower back. Uh-oh!

    In real life for me, the only times I develop a different enough amount of power to need to change my saddle position are on the track and racing 'cross. For both, I move my saddle forward some. My track bike is set up a little reachier too, I think.

    On my mountain bike, I feel like my riding position has more to do with handling the bike, and I've been happy enough to do endurance races without messing with it.
    "Don't buy upgrades; ride up grades." -Eddy Merckx

  20. #20
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    200
    Quote Originally Posted by TomP View Post
    ....One tip, if you can get your hands on a carpenter's laser level they are way nicer to work with than a plumb bob. Wives and their rolling eyes, you have my sympathy on that too
    A drywall square is another DIY bike fit tool that does the same thing as the plumb bob. I've found it useful to mark with a felt tip pen on my knee the correct location(s) then either set up my bike on an indoor trainer (preferably) or position myself in a doorway which allows for balance/stability. Have your lovely assistant place the short side of the square on the floor, which obviously must be level, then get on with measuring and recording your applicable position points.

    Staylor offers up some solid advice no matter what route you choose to dial in your fit, record and safely store all applicable data for future use. That info also comes in handy when you want to buy a new bike, test riding, traveling, etc.

  21. #21
    Nouveau Retrogrouch SuperModerator
    Reputation: shiggy's Avatar
    Join Date
    Dec 1998
    Posts
    48,052

    Saddle Fore Aft Position for long rides ....

    Quote Originally Posted by TomP View Post
    That hat is one of my prized possessions. I only wear it on special occasions.

    CCP was a great experience. But next time I'm in Oak Ridge/Westfir I'm just going to ride and explore. I wasn't around for NEARLY long enough in '08 when I did the race. The only singletrack I saw was on the racecourse. One pre-ride (with Mtbr member jms) and then race day. I was working at a bike shop that summer and it was hard to get enough time to really do it during the high season at the beginning of summer. Four days of driving from central CO, three days in Westfir. Not enough time!
    Late Sept/Oct is a great time to ride around Oakridge. Every trail will be open and the bugs are gone from the high country.
    mtbtires.com
    The trouble with common sense is it is no longer common

  22. #22
    Team Velveeta™
    Reputation: TomP's Avatar
    Join Date
    Jan 2004
    Posts
    2,226
    Quote Originally Posted by jms View Post
    No one I'd rather get lost on a pre ride with than you Tom : )
    Great place to get lost too. That Tire Mountain Trail is awesome.

    Can't believe that's been 5 years! My how the years march by.
    Tom Purvis - Salida, CO - http://teamvelveeta.tom-purvis.com

    "I like my wimmen like I like my beer--cold and bitter!"

  23. #23
    Feral Roadie
    Reputation: bbense's Avatar
    Join Date
    May 2010
    Posts
    729
    There's no magic about KOPS. It's just an easy to figure out starting point. Human beings ( especially young ones ) are incredibly adaptable, every bike position is a compromise in aero, power and comfort.

    The Myth of K.O.P.S.

    I am generally way way behind KOPS. But my bike position is optimized to keep my 52 year old knees happy riding 8hrs at a time, not necessarily for power.

  24. #24
    mtbr member
    Reputation: mudge's Avatar
    Join Date
    May 2010
    Posts
    1,127
    Quote Originally Posted by bbense View Post
    There's no magic about KOPS. It's just an easy to figure out starting point. Human beings ( especially young ones ) are incredibly adaptable, every bike position is a compromise in aero, power and comfort.

    The Myth of K.O.P.S.

    I am generally way way behind KOPS. But my bike position is optimized to keep my 52 year old knees happy riding 8hrs at a time, not necessarily for power.
    Not saying that KOPS is the be all/end all of positioning arguments, but things have changed significantly since 1998 in terms of how fit is looked at. FWIW, I just underwent a Retul fit on both my mtb and road bike, and while they didn't put me at KOPS, I'm a lot closer than I was.

Similar Threads

  1. Adjusting saddle fore-aft
    By Eyetattoo in forum General Discussion
    Replies: 19
    Last Post: 10-29-2012, 10:57 AM
  2. Saddle Position compared to your road bike
    By Slow Eddie in forum 29er Components
    Replies: 10
    Last Post: 05-31-2012, 09:14 PM
  3. Rear derailleur Fore/Aft position
    By amgine in forum Beginner's Corner
    Replies: 5
    Last Post: 05-07-2012, 09:37 AM
  4. Saddle fit/position quesion
    By matthawk7 in forum Beginner's Corner
    Replies: 6
    Last Post: 04-22-2012, 06:15 PM
  5. Seatpost clamp fore-aft position on saddle rails.
    By What&son in forum Bike and Frame discussion
    Replies: 3
    Last Post: 06-27-2011, 01:21 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •