1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Please interpret my bike fit so I can set my bike up

Discussion in 'Bicycle Mechanics and Repairs' started by doyler78, 20 Jun 2008.

  1. doyler78

    doyler78 Well-Known Member

    Location:
    Co Down, Ireland
    Just got my new Planet X Ti Sportive bike. Looks fantastic and seems so light compared to my current flat bar. Anyway I want to get this set up right so I got a bike fitting in LBS who were going to set it up for me however that fell through as they were having supply problems so had to go direct.

    Anyway I am left with a bike fit image which you can see here:

    [​IMG]

    http://www.flickr.com/photos/14838736@N04/2595163871/sizes/l/

    which I meant I was able to get to the correct size cranks and bars and frame ie medium frame with 170mm cranks and 400mm handlebar.

    My problem is I now have my bike but not sure what height it is telling me my saddle should be set to and where I measure from/to in order to set it once I do know how. Same problem with handlebar height though I'm not sure that these can just be raised. Looks to be that I need some sort of bung to raise if it is necessary. Then how far should my saddle be set back and again where am I measuring from and to.

    Can anyone advise please?

    Bought a damn white spesh toupe saddle for it however I was getting a white carbon frame at that time and now the white saddle will just not cut it with all the black on the rest of the bike so will have to get a new black saddle and ebay the old one.
     
  2. OP
    OP
    doyler78

    doyler78 Well-Known Member

    Location:
    Co Down, Ireland
    Ok I think I have figured it out.

    The seat should be 682mm from the centre of the bottom bracket to centre of the seatpost.

    The saddle should be 483mm+194mm= 677mm from the middle of the stem at the bar side to the centre of the seatpost.

    The handlebars should be 480mm+100mm=580mm measuring in a straight vertical plane from the centre of the bottom bracket to the centre of the bar at the stem.

    Am I right?
     
  3. Danny

    Danny Legendary Member

    Location:
    York
    I got one of these drawings recently and it took me ages to figure out what the heck it all meant - despite them running through it about three times in the shop :evil:

    I think you are correct in your translation of the drawing apart from one thing.

    My understanding is I think the seat should be 682 mm from the centre of the bb to the top of the saddle as opposed to the seatpost.

    At least that's how I interpreted that measurement - but would be grateful to know if anyone thinks I've got that wrong.
     
  4. OP
    OP
    doyler78

    doyler78 Well-Known Member

    Location:
    Co Down, Ireland
    Ahh yes. Having looked at that drawing again I would definitely agree with that and that of course makes perfect sense as where my ass is sat is more important than where the top of the seat tube is.

    Thanks. Have to nip into the shop today and get a black seat for it however it is chucking it down where I am so don't know if I will get out on it today or not and tomorrow doesn't look much better. Then I am away on 2 weeks holidays from tomorrow evening. Hoping I get just a clear hour to give a bit of wellie to make sure everything seems ok and to get a quick chance to check how it all feels fit wise and performance wise. Was dry most of the week. Just my luck the weather changes when I have finally got this :smile:

    As a matter of interest how did you find your setup was for you by using this? Did it feel more natural and did you see any difference in niggles you might have had before?
     
  5. RedBike

    RedBike New Member

    Location:
    Beside the road
    If your new frames different to the one in the diagram then wont all the measurements be wrong?
     
  6. OP
    OP
    doyler78

    doyler78 Well-Known Member

    Location:
    Co Down, Ireland
    Haven't a clue. I would say the handlebar height there can be no question about as it is measured in a vertical plane therefore it will be the same on any bike. Likewise the fore/aft position of the saddle is measured in a straight line across the bike therefore that distance would be same no matter what bike you are on (of course if the bike is big/small enough to make the adjustments necessary). The seat height I am not so sure on as it is measured at the angle of the seat tube therefore if the angle is greater or smaller than the diagram then would that affect the seat height? Don't know the answer to that one myself. I would have to dig out my old maths books for that one. Anybody else?
     
  7. OP
    OP
    doyler78

    doyler78 Well-Known Member

    Location:
    Co Down, Ireland
    Ok think I have figured out another way of measuring the seat height that will not therefore be dependent on any angles.

    That is to take 480mm+100mm+74mm=654mm if the you measure from the centre of the bottom bracket to the top of the seat in a vertical plane (ie no angle - straight up).
     
  8. 02GF74

    02GF74 Über Member

    1. set the crank so it is parallel to the seat tube.
    2. place heel of foot onto pedal and adjust the seat height until your leg is stright.

    when you foot is in normal pedalling position, the knee is ever so slightly bent with the pedal at its lowest position.

    handlebars and stem are to peersonal preference.