User Tag List

Likes Likes:  0
Results 1 to 12 of 12

Thread: Seat Tube Angle vs. saddle set back vs weight distribution

  1. #1
    Join Date
    Jan 2012
    Posts
    4
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Seat Tube Angle vs. saddle set back vs weight distribution

    This is a follow up to my previous "fitting dilemma" post (thanks for the great feedback by the way). I have been thinking more and more about frame geometry and what might be ideal for me, or at least as close to ideal as possible...

    I'll try my best to ask in a clear way: I am currently on an older size 56 EMX 5 which has pretty laid back geometry - specifically the seat tube angle is 72.5 degrees. As I pointed out in my fitting dilemma post, I found that using the provided set back seat post had me really, really far behind KOPS and feeling like I might be loosing power just clawing at the pedals with my hamstrings and not really using all aspects of my pedal stroke. After working with a fitter, I am now on a straight post with my saddle pretty far forward (still behind KOPS), but now struggle with feeling to heavy on my hands... It also just strikes me as wrong to be "fighting" the frame design by going with such a radical departure from the intended set up.

    If I look at some other frames, for example a BMC Team Machine (just to illustrate my question), the seat tube angle is a steeper 73.5.

    It seems to me that with a steeper seat tube angle, I would have my saddle further back to achieve the same position (nose of saddle relative to bottom bracket) and be more within the frames intended set up. My question (long winded as it is) - is would this positively effect my weight distribution? In other words, get at least a little closer to KOPS (which i fully appreciate most folks dismiss anyway) but have a better weight distribution between my hands and my ass?

    I hope this question makes sense - if so please share any thoughts. I am working on setting up an appointment with a fitter in the coming weeks, but still would be curious to get some thoughts on this question. Cheers!
     

  2. #2
    Join Date
    Nov 2009
    Location
    Dayton, Ohio
    Posts
    131
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Seat Tube Angle vs. saddle set back vs weight distribution

    well no matter where you put your hands, feed and ass your bicycle could be a squiggle. so the frame isn't necessarily the issue in anything yet.
    figure out your fit first. 100%.
    where is the front axle in all of this?
    did you move your hands when you moved your ass around?
     

  3. #3
    Join Date
    Oct 2010
    Location
    Shakopee, Minnesota, United States
    Posts
    2,143
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Seat Tube Angle vs. saddle set back vs weight distribution

    Just gonna say if the effer is stiff it won't squiggle.... Go on have fun with that....

  4. #4
    Join Date
    Aug 2010
    Location
    bend
    Posts
    1,493
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Seat Tube Angle vs. saddle set back vs weight distribution

    sta is only a relevant variable for providing a means to secure a seat to a bike using standard available equipment (25mm setback post or topper ideally) and provide an appropriate range of fit. if you've got dialed position and a seat under your butt, slack or no is not gonna matter. you never sit directly atop the st, your weight is always cantilevered over the the bike and the force is vectored fore/aft accordingly
     

  5. #5
    Join Date
    Mar 2009
    Location
    Meriden CT
    Posts
    1,294
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Seat Tube Angle vs. saddle set back vs weight distribution

    As you shift your position forward, I believe you'll have to raise your bars to take the weight off your hands, which if I recall correctly, you complained about in your original thread. Of course, raising the handlebars isn't so easy to do with threadless steerers, especially after they've been cut.

    You could try an experiment and buy an el cheapo stem that can flip-flop to change it's rise such as an 84 degree Ritchey (not that Ritchey's are el cheapo; just that they provide the +/- 6 degree flippy-floppy). Try the higher rise position to see if that points you in the direction you want to go.

    The more I read about how you're unable to achieve KOPS regardless of the seatpost and with your existing STA, I'm thinking even if you were to buy a frame with a steeper seat tube angle so you can achieve KOPS, you would have to raise your bars to get the pressure off your hands. In other words, you might not have that cool looking slammed stem that's the fashion now. I'd ignore fashion.

    A 56cm frame with a 72.5 STA is kinda slack but increasing the STA 1 degree will only get you about 14mm of "closeness" to KOPS. Will that be enough?

    Another option is to try a SHORTER stem. That'll change your body angle and bring some weight off your arms. Again; buy a cheap stem until you finalize your position, then buy a blingy one.
     

  6. #6
    Join Date
    Oct 2010
    Location
    Northern VA
    Posts
    935
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Seat Tube Angle vs. saddle set back vs weight distribution

    My internet diagnosis tells me you might need a longer, shorter, higher, or lower stem. All kidding aside ....

    You mentioned working with a fitter. The fitter should have provided you with measured-out contact points, ie, where your ass, hands and feet need to be in relation to one another, such as, saddle height, saddle setback from BB, saddle-to-bar drop, saddle-to-center of bars, etc. Ignore frame angles and any other voodoo you hear about 'ideal' post setback or 'ideal' stem length. Your fitted-measurements/ established contact points should be your starting point.

    FWIW, I too ride a Merckx. I use a 5mm setback post with a 13cm stem. All of my other bikes use 20mm setback posts with shorter stems. Among my 5 or so bikes, ALL of the fitted-measurements, such as saddle setback, saddle-to-bar drop, and saddle-to-center of bars, are within 1-2mm of one another.
     

  7. #7
    Join Date
    Jul 2008
    Location
    Seattle, WA
    Posts
    874
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Seat Tube Angle vs. saddle set back vs weight distribution

    Quote Originally Posted by Cfish View Post
    .........and feeling like I might be losing power just clawing at the pedals with my hamstrings and not really using all aspects of my pedal stroke. .......
    Seems to me that you need some objective evidence that having more setback was/is detrimental to your power generation. Nothing wrong with riding like Eddie intended you to--get your butt back, use your glutes, hamstrings, and quads. Proper pedaling is more than just saddle position.
     

  8. #8
    Join Date
    Mar 2009
    Location
    worlds biggest island
    Posts
    1,699
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Seat Tube Angle vs. saddle set back vs weight distribution

    Do yourself a huge favor and get a copy of Steve Hogg's DVD "Sitting Pretty", I'm sure it will enlighten you greatly.
    Bill
     

  9. #9
    Join Date
    Jun 2008
    Location
    Cannon County TN
    Posts
    5,733
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Seat Tube Angle vs. saddle set back vs weight distribution

    Mr. Hogg, our own David Kirk, and Mr. Peter White have published variations upon the same theme of finding your proper setback. Please look one (or all) of those up. Dave's is on here in some compilation thread.

    For most folks sliding the saddle on the post is plenty...but for those like me, a very offset post or new STA is required to get to the setback necessary to provide proper balance which will give the rider most excellent handling and proper muscle recruitment through his/her pedalstroke.

    There is no measuring-it is done dynamically by feel.* There is no point (in measuring) until you find your setback. THEN measure it and stay close to that for any machine hereafter except for TT and other weird things.

    *Wise old builders and fitters may be able to dial this in by measurements and interview, but the dynamic testing makes it easy for those learning about fit to find the right setback.

    Fitting starts at the cleat, then hips, then let the compromises begin with bar/stem setups. Don't compromise the lower half of the body. Never use setback to adjust reach.






  10. #10
    Join Date
    Mar 2009
    Location
    worlds biggest island
    Posts
    1,699
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Seat Tube Angle vs. saddle set back vs weight distribution

    Quote Originally Posted by WadePatton View Post
    Mr. Hogg, our own David Kirk, and Mr. Peter White have published variations upon the same theme of finding your proper setback. Please look one (or all) of those up. Dave's is on here in some compilation thread.

    For most folks sliding the saddle on the post is plenty...but for those like me, a very offset post or new STA is required to get to the setback necessary to provide proper balance which will give the rider most excellent handling and proper muscle recruitment through his/her pedalstroke.

    There is no measuring-it is done dynamically by feel.* There is no point (in measuring) until you find your setback. THEN measure it and stay close to that for any machine hereafter except for TT and other weird things.

    *Wise old builders and fitters may be able to dial this in by measurements and interview, but the dynamic testing makes it easy for those learning about fit to find the right setback.

    Fitting starts at the cleat, then hips, then let the compromises begin with bar/stem setups. Don't compromise the lower half of the body. Never use setback to adjust reach.
    That's what I'm talkin about.
     

  11. #11
    Join Date
    Oct 2009
    Location
    CT
    Posts
    52
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Seat Tube Angle vs. saddle set back vs weight distribution

    I have 3 road bikes, all with the same peddles and saddles. They are setup within mm of each other. However after spending considerable time on one, (weeks) then riding another, the feel is different enough to give me leg muscle twinges etc. after a 1/2 hour or so on it. After getting comfortable on it (a week or so) then swiching back, the same feelings occur. Seems just a mm or so diffrence with something one way or the other makes me feel this.

    Does this happen with any of you with muliple bikes?
     

  12. #12
    Join Date
    Oct 2010
    Location
    Shakopee, Minnesota, United States
    Posts
    2,143
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: Seat Tube Angle vs. saddle set back vs weight distribution

    Quote Originally Posted by bikeman View Post
    I have 3 road bikes, all with the same peddles and saddles. They are setup within mm of each other. However after spending considerable time on one, (weeks) then riding another, the feel is different enough to give me leg muscle twinges etc. after a 1/2 hour or so on it. After getting comfortable on it (a week or so) then swiching back, the same feelings occur. Seems just a mm or so diffrence with something one way or the other makes me feel this.

    Does this happen with any of you with muliple bikes?
    Yes. And you have to take flex into account as well. They aren't all the same.

Similar Threads

  1. Seat tube slotting setup procedure
    By zank in forum The Knowledge
    Replies: 28
    Last Post: 12-14-2015, 03:08 PM
  2. Back to Back Days -- Block(head) training?
    By Watoni in forum General Discussion
    Replies: 3
    Last Post: 08-11-2011, 06:12 PM
  3. Replies: 18
    Last Post: 05-10-2011, 07:41 PM
  4. head tube angle on MTB bikes
    By luaxwe in forum General Discussion
    Replies: 0
    Last Post: 11-01-2010, 10:58 PM
  5. multi channel retail distribution (from cc)
    By DCT in forum General Discussion
    Replies: 28
    Last Post: 08-11-2010, 01:10 PM

Bookmarks

Bookmarks

Posting Permissions

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