• This topic has 17 replies, 14 voices, and was last updated 11 years ago by DezB.
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  • Bar width and stem length. Is there a formula?
  • uphillcursing
    Free Member

    Please bear with me here. May be some rambling to follow.
    I have in the garage an old Cannondale Jeckyl from the turn of the Century. I recently had the idea of resurrecting it. However, a post fettling ride proved that it is not going to fill the gap for longer ride comfort.
    Narrow bars at 630mm and long stem giving very much a head down arse up position that my old bones will not wear for all day jaunts. I know that wider bars will exaggerate this even more unless I get a shorter stem. This is not going to be a cheap enterprise due to the Lefty stem (25.4 to further complicate things) so I want to get it right.
    Is there a formula that might help me get the wider bars/shorter stem plus decreasing the overall reach without trail and error?

    Any help appreciated. Also please feel free to point any flaws in my thinking.

    mikewsmith
    Free Member

    No

    try a broom handle/borrow bars/stem/tape measure

    I used to have 3/4 spare stems and some bars around that would make this easy

    DezB
    Free Member

    I don’t think there’s a magic formula.
    Most people just buy what they’re told to by the mags 😉

    50mm X 740mm is the MBR standard if you want more than a 7/10, I believe.

    sas78
    Full Member

    I tried using some trig to work it out, but it’s overkill. I then measured the distance to the end of the bars in the original setup then worked out backwards what stem length I needed to get the same reach with a specific bar width…

    complex I know!

    uphillcursing
    Free Member

    If it is any help bar width will be a highly unfashionable 680ish max. No need for Gnar credentials. Just a point where old shoulders feel comfortable for longer rides.

    If it were a normal stem i could just do the trail and error approach. Sadly the Lefty rules this out without exercising the “flexible friend”.

    cookeaa
    Full Member

    There isn’t a formula that I’m aware of, but I can see the case for someone trying to work one out based on the rider and desired position.

    As a basic starting point I think it would need to be based on a factoring/scaling from riders shoulder width and/or Arm length?

    It seems odd, that given the level of measurment and analysis that is carried out on Road, TT, Track and even XC bikes layout that there’s not so much applied to AM/DH/FR type MTBs…

    Wider bars/shorter stem is better? it must all come down to the rider and the application at the end of the day….

    BigJohn
    Full Member

    As they are both essentially fashion items the formula is simple. Widest bars you can find and shortest stem.

    mikewsmith
    Free Member

    As they are both essentially fashion items the formula is simple. Widest bars you can find and shortest stem.

    and a saucer of milk for yours John

    Teetosugars
    Free Member

    50mm X 740mm is the MBR standard if you want more than a 7/10, I believe.

    😆

    smiff
    Free Member

    i think there is a formula, but i don’t know it is! all i know the right stem length seems to follow closely from head angle. slack ha, shorter stem, steeper HA, longer stem. when i change fork, or travel, or even headset lower cup – anything that changes HA, i always end up changing stem to make it feel right. this has happened on several bikes and forks now. you have a small amount of adjustment from bar tilt also, since changing grip position is effectively same thing. iow, for particular fork, there’s a particular stem that makes steering “right”. this unfortunately means little adjustment of frame fit possible.
    bar width is mostly about comfort and fitting through trees though. again YMMV.

    mjsmke
    Full Member

    For practicality buy some wide bars and move the grips in. The cut the bars down when you find the optimum width. As for stems, just try some if can borrow them off mates to get a feel of the handling/position pros and cons before buying an expensive one.

    For fashion. Take a 5ft broom handle and bolt it directly onto of the steerer tube. No need for a stem.

    glupton1976
    Free Member

    E=mc^2

    That’s the formula.

    NormalMan
    Full Member

    Not sure if this is what you are looking for but will this formula do:
    http://richardcunningham.pinkbike.com/blog/Tech-Tuesday-Handlebars-How-Wide-Affects-Your-Ride.html

    😉

    muckytee
    Free Member

    So we are trying to find the length from the handle bar to the riders chest. The longer the length the more upright the rider will be.

    Therefore I would get a broom handle or similar, mark off 630mm, then any other lengths you are considering say 710mm.

    I would then hold the broom handle straight in front of me with my back against the wall and get a friend to measure the distance from the broom handle to my chest, I would then add the length of the stem to get my final measurement.

    So for me with 630mm bars, the distance from my chest to the bar is 600mm.

    with 710mm bars, the distance from my chest to the bar is 510mm.

    If therefore I ran my 630mm bars with a 0mm stem I would require a 90mm stem to achieve a similar effect with the 710mm bars.

    This is all a bit abstract and needs refinement but hey 😛

    smallpaws
    Free Member

    780mm bar X 60mm stem = AWESOME ride!!!

    uphillcursing
    Free Member

    LOL. Only on STW.

    I guess I shall see if I can find a Lefty stem in the region of 90cm in place of the 120 one I have currently. Then see what bars suit.

    What a place this is at times!

    chiefgrooveguru
    Full Member

    Yes. Too wide = catching on trees and crashing. Too short = smacking knees on bars/shifters.

    DezB
    Free Member

    0mm stem

    SSSHHH! Everyone will be after those!

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