seat fore and aft positioning

Frank pole
Frank pole Posts: 112
edited March 2013 in Road general
Seen a few vids on getting correct seat fore and aft

With my seat slid all the way back on it's rails I still can't get back far enough - is this a common problem?

Comments

  • mikelskas
    mikelskas Posts: 57
    Should not be a problem if your bike is correctly sized for you.

    You could try a seatpost with a 20mm setback if you dont already have one?
    2011 Jamis Ventura Race
    2016 BMC TeamMachine SLR02
  • Calpol
    Calpol Posts: 1,039
    Not if you have the right size frame. Sounds like you have long arms and torso on too short a top tube. Either that or your stem is too short.
  • thefd
    thefd Posts: 1,021
    Frank pole wrote:
    Seen a few vids on getting correct seat fore and aft

    With my seat slid all the way back on it's rails I still can't get back far enough - is this a common problem?
    What do you mean by "can't get back far enough"? Do you mean when on the handle bars? If so try a longer stem, or the frame is too small!
    2017 - Caadx
    2016 - Cervelo R3
    2013 - R872
    2010 - Spesh Tarmac
  • Frank pole
    Frank pole Posts: 112
    I'm 6.1 tall and run a 58 cm frame, my seat pillar has a slight offset (not as much as 20mm)but using a plumb Bob from just under knee cap it still drops in front of pedal
  • Frank pole
    Frank pole Posts: 112
    Thefd - sorry I should have explained better, my knees seem to be to far forward
  • smidsy
    smidsy Posts: 5,273
    Frank pole wrote:
    Thefd - sorry I should have explained better, my knees seem to be to far forward

    In relation to what?
    Yellow is the new Black.
  • pinarellokid
    pinarellokid Posts: 1,208
    the knee should be in line with the pedal axle. iv read... but wasnt sure if its the front of the knee or the middle
    Specialized S Works SL2 . Campagnolo Record 11spd. rolling on Campag Zonda wheels

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  • MattyDeez
    MattyDeez Posts: 54
    Frank pole wrote:
    I'm 6.1 tall and run a 58 cm frame, my seat pillar has a slight offset (not as much as 20mm)but using a plumb Bob from just under knee cap it still drops in front of pedal

    I'm 6' 2", my frame is a 54. But you might have longer limbs though!

    First thing to do is try the old trick of arm on your seat and see if your middle finger touches your stem clamp to the steerer tube.

    Its all proportional. To get seat height, rest your armpit on your saddle and your middle finger should be in the middle of the bottom bracket. (Give or take anyways, it's not that accurate).
  • sungod
    sungod Posts: 17,357
    it's probably worth starting from scratch, saddle position depends not only on limb size and proportions, but also on flexibility, it's the basis of all the subsequent adjustments so worth taking time to get it right (plus cleat position of course!)

    the 'knee over pedal spindle - kops' positioning is widely used, but afaik there's no proof it results in 'correct' positioning, even on average, let alone for any particular individual

    this is interesting on the topic...

    http://www.stevehoggbikefitting.com/blo ... can-it-be/
    https://www.stevehoggbikefitting.com/bl ... oad-bikes/

    if you can't even get to kops position, a post with more setback is probably a good investment, then with the extra range you can look for the best position for you
    my bike - faster than god's and twice as shiny
  • team47b
    team47b Posts: 6,425
    If you take a pair of your trousers and hold the waistband around your neck it should fit the circumference of your neck exactly as your waist should be twice that of your neck.

    If not your saddle is too high :D
    my isetta is a 300cc bike
  • Frank pole
    Frank pole Posts: 112
    Cheers for the links sungod - site looks interesting!

    Definitely going to get a 25mm setback seat post as my knee over hangs pedal axle by a couple of inches
  • Pross
    Pross Posts: 43,463
    Not seen the advice to use arm length to determine seat height before - different!
  • thefd
    thefd Posts: 1,021
    Pross wrote:
    Not seen the advice to use arm length to determine seat height before - different!
    I've not either - but surely this doesn't take into account for crank length.
    MattyDeez wrote:
    Its all proportional. To get seat height, rest your armpit on your saddle and your middle finger should be in the middle of the bottom bracket. (Give or take anyways, it's not that accurate).
    Matty does say it's not that accurate which makes me wonder why would anyone use it?
    2017 - Caadx
    2016 - Cervelo R3
    2013 - R872
    2010 - Spesh Tarmac
  • MichaelW
    MichaelW Posts: 2,164
    Saddle fore-aft is independent of the handlebar position or reach adjustment.
    It is dependant on the ratio of your upper leg/lower leg NOT your total leg length or your height.
    It is also affected by the length of your cranks. If your saddle is not far enough back, the problem may be that your pedal is not far enough forward, are your cranks long enough? Switching from 170 to 175mm will gain you an extra 5mm at the 3:00 position.
    If you have extra long femurs then you would need more saddle layback. In the olden days, framebuilders used to slacken the angle of the frame in this situation but you can now buy seatposts with extra layback. It makes no difference how you achieve the correct layback.
  • John.T
    John.T Posts: 3,698
    Switching from 170 to 175mm will gain you an extra 5mm at the 3:00 position.
    No it does not. It only gives you 2.5mm more. And this is not a reason to use a particular crank length. Longer cranks are suited to longer thighs though.
    The KOPS method of setting saddle set-back, while disputed, is still a good starting point for fine tuning as it gets you close while taking into account thigh and crank length. This and saddle height should be the first things you set on a bike and bars fitted to suit this.
    My Fleet.
  • keef66
    keef66 Posts: 13,123
    John.T wrote:
    Switching from 170 to 175mm will gain you an extra 5mm at the 3:00 position.
    No it does not. It only gives you 2.5mm more. And this is not a reason to use a particular crank length. Longer cranks are suited to longer thighs though.
    The KOPS method of setting saddle set-back, while disputed, is still a good starting point for fine tuning as it gets you close while taking into account thigh and crank length. This and saddle height should be the first things you set on a bike and bars fitted to suit this.

    If the crank is 5mm longer, surely the pedal is 5mm further forward when the crank is at 3 o'clock? Or am I missing something?
  • winlikefin
    winlikefin Posts: 32
    Hi - I would suggest getting a 'proper' bike fit.
    For years I had been riding in the same position - saddle slammed right back on the rails.
    Last week I had a retul fit done at VeloCafeMagasin in Belfast. My saddle has come forward and up. Sean was able to identify an asymmetry in my pedalling using the retul sensors. I will be going back in a few weeks for a follow up session to see how I have adapted to the 'new' position.
    Just because you feel that you are sitting too far forward does not necessarily mean that you are! The KOPS system (as stated above) has it's opponents.
    In relation to my new fit - I feel that I'm sitting more 'on' the bike now. Previously the bike had been 'under' me - not a great description but it's difficult to quantify. I think I like it - a few more miles will help me decide!
  • styxd
    styxd Posts: 3,234
    MattyDeez wrote:
    Its all proportional. To get seat height, rest your armpit on your saddle and your middle finger should be in the middle of the bottom bracket. (Give or take anyways, it's not that accurate).

    You're 22 days early with that one
  • John.T
    John.T Posts: 3,698
    keef66 wrote:
    John.T wrote:
    Switching from 170 to 175mm will gain you an extra 5mm at the 3:00 position.
    No it does not. It only gives you 2.5mm more. And this is not a reason to use a particular crank length. Longer cranks are suited to longer thighs though.
    The KOPS method of setting saddle set-back, while disputed, is still a good starting point for fine tuning as it gets you close while taking into account thigh and crank length. This and saddle height should be the first things you set on a bike and bars fitted to suit this.

    If the crank is 5mm longer, surely the pedal is 5mm further forward when the crank is at 3 o'clock? Or am I missing something?
    OOOPS. No I am.
    My Fleet.

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