seat fore aft position

andy610
andy610 Posts: 602
edited April 2009 in Road beginners
ive just moved my seat forward, so my small bone behind the kneecap is in the middle of the pedal spindal when i use a plumbob, but now there is more pressure on the top of my knees, ive had my bike for 2 yrs now and still not feel right on it.
how will i know when the seat is right

Comments

  • justresting
    justresting Posts: 292
    think I've read somewhere in forums that you move the saddle one way for pain at front of knee, and the other for pain behind. Sorry can't b more helpful but on way out to work ! But maybe type knee pain into search.
    ' From the sharks in the penthouse,
    to the rats in the basement,
    its not that far '
  • ride_whenever
    ride_whenever Posts: 13,279
    i would recommend a professional bike fitting.
    Neeermad
    Carbon 456
    456 lefty
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  • kingrollo
    kingrollo Posts: 3,198
    ride_whenever wrote:
    i would recommend a professional bike fitting.

    +1 for bike fitting

    I almost gave up cycling due to injuries , a proffersional bike fitting was last chance saloon - what a difference - that was 10 years ago
  • shakey88
    shakey88 Posts: 289
    Anyone know of a bike fitting service in the hants area?
  • keef66
    keef66 Posts: 13,123
    You say " small bone behind the kneecap". Do you mean the bump just below the kneecap? This is where you should be measuring from.

    Basic fitting does it in this order:

    Seat height (leg nearly straight with heel on pedal) A proper fitting will involve measuring the knee angle when clipped in properly
    Seat fore / aft (knee over pedal spindle) Saddle dead horizontal
    Reach and drop to the bars

    There are those who think the knee over pedal spindle thing isn't neccessarily the best position for all riders / bikes. have a google for KOPS
  • redddraggon
    redddraggon Posts: 10,862
    KOPS is not a rule, it's just a suggestion. I've found out my saddle height and setback through trial and error.
    I like bikes...

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  • John.T
    John.T Posts: 3,698
    edited April 2009
    +1 Red. KOPS is just a good starting point for fine tuneing. I have ended up 1cm in front.
    Andy. You say you have moved the saddle forward. If so you will also have effectively lowered it a little. A saddle that is too low loads the quads more and you will feel pressure there. The heel on pedal with slight knee bend method is fairly good for finding a starting position. From there I raise the saddle a small amount at a time until the pelvis just starts to rock when pedaling normally. Then lower it a little until it does not move. It is helpful to have someone ride behind you for this.
    You say " small bone behind the kneecap". Do you mean the bump just below the kneecap? This is where you should be measuring from.
    Quite right keef
    My Fleet.
  • Kneesaway
    Kneesaway Posts: 56
    Hi

    I suggest you have a look at BikeDynamics.co.uk and follow a link to YouTube

    http://www.youtube.com/watch?v=qT6UMCy6 ... r_embedded

    There is some interesting stuff here on saddle position.[/url]
  • andy610
    andy610 Posts: 602
    i went to my local evans bike shop and they said my seat needed to be a lot further back so i moved it back and then i was nearly 30mm before pedal axle, which cant of been right, so ive moved it forward again
  • redddraggon
    redddraggon Posts: 10,862
    andy610 wrote:
    i went to my local evans bike shop and they said my seat needed to be a lot further back so i moved it back and then i was nearly 30mm before pedal axle, which cant of been right, so ive moved it forward again

    There's your problem there...Evans giving out decent advice is not a common occurrence.....
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  • dennisn
    dennisn Posts: 10,601
    redddraggon wrote:
    KOPS is not a rule, it's just a suggestion. I've found out my saddle height and setback through trial and error.

    I'm with you on KOPS. For lack of any other real testing and science on the subject
    I've got to go with it as a starting point. Even if no one can come up with a reason for it.

    Dennis Noward
  • andy610
    andy610 Posts: 602
    so can i turn my 20mm setback fsa sl250 seatpost to get seat nearer the bars
  • redddraggon
    redddraggon Posts: 10,862
    I recommend getting a non setback post like a Thomson. Turning the post might put you far too forward over the BB.
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  • andy610
    andy610 Posts: 602
    if the seat goes too far forward over bb what will happen, knee pain i guess.
  • John.T
    John.T Posts: 3,698
    No. Sore arms. You probably won't be able to get much power out unless you rotate your whole body as in a TT position. Not very comfortable for general riding. Can you post a picture of you on the bike with the crank level and foreward.
    Don't try reversing the seatpost. It would move the clamp foreward by 4cm which is a massive amount. I would say that anything more than 2cm either way from KOPS is fairly unusual. (Awaits posts from folk who have it more than this but the ones who don't will not bother.) You would probably find the clamp does not work wrong way round anyway.
    Get your saddle height right and go back to KOPS. Then start adjusting one thing at a time by small amounts. Never more than 5mm and take notes so you know which way things are going.
    My Fleet.
  • ohlala!
    ohlala! Posts: 121
    I found my comfortable position through trial and error, basically what you're looking for is how you can get as natural as possible on the bike - but not slouching.
  • NaB
    NaB Posts: 105
    look at how most pros have their bikes set up on cycling news or such like...there's no harm in being a bit behind the bb..means you can get more power out when seated. I've had front of knee pain which i solved by raising the saddle and moving it back to get a more stretched out position. This might not be the answer for you but I think its worth trying!
  • dag_on_a_bike
    dag_on_a_bike Posts: 581
    shakey88 wrote:
    Anyone know of a bike fitting service in the hants area?

    I'm in Hampshire too, but it's a big county.

    I'm in north Hampshire so Hants/Berks/Surrey borders area for bike fitting?
    There's no such thing as too old.
  • BikeDynamics
    BikeDynamics Posts: 52
    A few comments on this thread

    We are a Bike Fitting service based in Warwickshire. One of my customers drove from Portsmouth to get here so I guess there may not be any similar offerings in Hants/Berks.
    See http://bikedynamics.co.uk/index.html if you fancy a trip up the M40.

    KOPS has no theoretical justification but is a good starting point as it places your Centre of Gravity close to the line of action of pedalling forces. People make the mistake of moving their saddle around and looking for differences in power. You should be looking for differences in upper body movement, the calmer the better.

    Most people I fit end up a few mm in front of the KOPS ideal. The static KOPS position is often in front of the dynamic (whilst pedalling) position so it should only be regarded as a starting point.

    Going too far backwards is a bad idea unless you are very flexible. Hip angle and maximum knee angle are interelated via the length of your hamstrings. Going back will tighten the hip and make you want to drop your saddle, reducing the efficiency of your knee extensors. Unlike the Pro's most of us have sedentary jobs and don't do enough stretching so you could just end up with lower back pain.

    BikeDynamics.co.uk

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