Advertise on Bikeforums.net



User Tag List

Results 1 to 11 of 11
  1. #1
    Member
    Join Date
    May 2014
    Posts
    30
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Stem length for a more aero position

    Hey all,


    I'm 5 feet 7.5 inches, and ride a 52 cm road bike. Right now I'm using a 90mm stem and the bike feels perfectly balance.

    What I'm interested in is to be able to sit in a more aero position. Thus I will be moving my saddle foreward, and also the stem. So I was wondering, at what length does the stem becomes too long that bike handling and steering becomes compromised ?


    Thanks.

  2. #2
    coprolite fietsbob's Avatar
    Join Date
    Jun 2010
    Location
    NW,Oregon Coast
    My Bikes
    7
    Posts
    888
    Mentioned
    31 Post(s)
    Tagged
    0 Thread(s)
    so down in the drops is not aero enough ?

  3. #3
    Member
    Join Date
    May 2014
    Posts
    30
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    That will close down my hip angle, making it harder to sustain that position for a long period of time.

    Moving saddle forward, allow a more aero position while maintaining a wide enough hip angle to stay in that position for a longer period of time.

  4. #4
    Senior Member Fiery's Avatar
    Join Date
    Oct 2010
    Location
    Brussels, Belgium
    Posts
    554
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by ricefarmerr View Post
    So I was wondering, at what length does the stem becomes too long that bike handling and steering becomes compromised ?
    No set answer, as it depends greatly on your body size and proportions and your bicycle size and geometry.

    There are some general tendencies that you might expect to notice. At first, lengthening the stem will probably immediately feel worse when going slowly, as the steering will feel heavier and slower. But once you get up to speed, it is very likely that the front end will feel much more stable and better planted. However, if you reach a point where the stem is too long, you will know it because the rear wheel will now have too little weight on it and it will be unstable and skittish in turns. Again, at what point this might happen for you on your bicycle you will have to find out for yourself.

  5. #5
    johnliu@earthlink.net jyl's Avatar
    Join Date
    Aug 2006
    Location
    Portland OR
    My Bikes
    61 Bianchi Specialissima 71 Peugeot G50 7? P'geot PX10 74 Raleigh GranSport 75 P'geot UO8 78? Raleigh Team Pro 82 P'geot PSV 86 P'geot PX 91 Bridgestone MB0 92 B'stone XO1 97 Rans VRex 92 Cannondale R1000 94 B'stone MB5 97 Vitus 997
    Posts
    3,836
    Mentioned
    44 Post(s)
    Tagged
    0 Thread(s)
    I'm not clear. To get more aero, are you getting down in the drops or not?

    If you are not in the drops, you are not doing much to improve your aero drag. Longer stem + saddle forward won't help much if you are still up on the hoods.

    Basically, look at yourself from the side (have someone take a pictures, or ride by a reflective window). The closer to horizontal and flattened out your back is, the more aero.
    Your signature contains too many lines and must be shortened. You may only have up to 2 line(s). Long text may have been implicitly wrapped, causing it to be

  6. #6
    just another gosling Carbonfiberboy's Avatar
    Join Date
    Feb 2007
    Location
    Everett, WA
    My Bikes
    CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004
    Posts
    8,132
    Mentioned
    4 Post(s)
    Tagged
    1 Thread(s)
    You just have to try it. Reversed setback seatpost (set forward?), longer stem, etc. No one answer.

  7. #7
    Senior Member
    Join Date
    Apr 2013
    Location
    Glendale, CA
    My Bikes
    2013 Giant TCR Advanced SL4, 1989 Centurion Ironman Master Dave Scott
    Posts
    2,355
    Mentioned
    6 Post(s)
    Tagged
    0 Thread(s)
    I've heard 90-120mm is the sweet spot. I have used 80, 90, 100, 110 and 120 on various bikes. My current road is 120 and feels great.
    http://www.pedalroom.com/members/rms13

  8. #8
    Senior Member
    Join Date
    Sep 2013
    Posts
    428
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Moving everything forward doesn't make you more aero, it just puts you further forward. And the negative effect of closing the hip is a loss of power but you have to get pretty low for that to happen and working on hamstring flexibility will help though after a certain point some of the muscles in the hip actually stop being able to contract.

    Getting your shoulders and head low and your back as flat as possible are the way to get more aero. Core strength is important to maintaining the position and so is spending a lot of time riding that way.

  9. #9
    just another gosling Carbonfiberboy's Avatar
    Join Date
    Feb 2007
    Location
    Everett, WA
    My Bikes
    CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004
    Posts
    8,132
    Mentioned
    4 Post(s)
    Tagged
    1 Thread(s)
    There is also a UCI limit for saddle position:
    For endurance or all mass start events; road, track and cyclo-cross, the nose of the
    saddle must be a minimum of 5 cm behind a vertical line drawn up through the center of
    the crank axle. For speed events (track); sprint, 500m, 750m, kilometer and team
    sprint, the nose of the saddle may move forward inside this 5 cm dimension, but never
    beyond the center of the crank.
    https://s3.amazonaws.com/USACWeb/for...egulations.pdf

    As you can see in the photo of Cancellara in this article:
    UCI eases rules on time trial positions | Cyclingnews.com
    even with his saddle at the limit position, he still is perching his perineum on the nose to open his hip angle further.

  10. #10
    Member
    Join Date
    May 2014
    Posts
    30
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Carbonfiberboy View Post
    There is also a UCI limit for saddle position:
    https://s3.amazonaws.com/USACWeb/for...egulations.pdf

    As you can see in the photo of Cancellara in this article:
    UCI eases rules on time trial positions | Cyclingnews.com
    even with his saddle at the limit position, he still is perching his perineum on the nose to open his hip angle further.

    Thank you very much for the link.

  11. #11
    Senior Member
    Join Date
    Sep 2008
    Posts
    279
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Stem length has little effect on steering. The fact is you lean to turn. Bikes are different from cars that way. It's possible to get too low. At some point you lose power with increased drop. It's also possible to to have too much reach. At some point your saddle will be too far forward and the reach is so long that you're just too far forward. Your goal is to be as low as possible without being so low that you lose power. Your goal is to be forward enough with maximum reach without going too far. As the saddle goes forward you put increasing weight on your hands and toes. At some point you've gone too far. If your reach is so long that you can't maintain your saddle position and your sit bones slide forward of the sweet spot it's too long.
    Last edited by Clem von Jones; 06-04-14 at 09:15 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
  •