Height, size, reach..

chatlow
chatlow Posts: 845
edited April 2014 in Road general
Looking at a new bike and don't want to make the mistake of it being too big or small. I am 5'9" with a 32" inseam. So a fairly short torso. On paper I should be cycling a medium 54cm. Unfortunately one of the 54cm bikes I tried felt a little stretched out, so I've got the option of a shorter stem for the 54 or a longer stem on a 51cm. Does it matter which one I choose?

Comments

  • arran77
    arran77 Posts: 9,260
    If you're dead set on a particular make and model and don't want to change from that then within reason I'd err on the side of caution and go smaller as it's much easier to make a small bike bigger than vice versa.
    "Arran, you are like the Tony Benn of smut. You have never diluted your depravity and always stand by your beliefs. You have my respect sir and your wife my pity" :lol:

    seanoconn
  • Dezza
    Dezza Posts: 155
    Get a cycle fit. I wish I had before buying my first bikes, would have saved me a lot of cash and injury.
  • mfin
    mfin Posts: 6,729
    54cm frames can vary a lot. You actually need to at least understand Effective Toptube Length, Seattube Angle, Headtube Length and Bottom Bracket Drop, plus how they interact and affect the fit. (The 54cm part has nothing to do with any of these)
  • drlodge
    drlodge Posts: 4,826
    Sounds to me you are about a "54cm" frame size. The issue with going to a smaller frame is that you will also get a smaller head tube, which means the drop from saddle to bars will be even greater. I would seek some expert bike fit advice otherwise you risk making a big mistake.

    Do you feel simply too stretched out, or too much weight on your hands?
    WyndyMilla Massive Attack | Rourke 953 | Condor Italia 531 Pro | Boardman CX Pro | DT Swiss RR440 Tubeless Wheels
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  • chatlow
    chatlow Posts: 845
    drlodge wrote:
    Sounds to me you are about a "54cm" frame size. The issue with going to a smaller frame is that you will also get a smaller head tube, which means the drop from saddle to bars will be even greater. I would seek some expert bike fit advice otherwise you risk making a big mistake.

    Do you feel simply too stretched out, or too much weight on your hands?

    Both stretched out and too much weight on my hands. This bike is a 54cm and it's referring to top tube length, not seat tube, but I will look at the other aspects of bike fitting before I buy.
  • Moonbiker
    Moonbiker Posts: 1,706
    What bike was it?
  • cornerblock
    cornerblock Posts: 3,228
    Dezza wrote:
    Get a cycle fit. I wish I had before buying my first bikes, would have saved me a lot of cash and injury.

    ^^^^^^^^^^^

    This is the best advice.
  • jonny_trousers
    jonny_trousers Posts: 3,588
    drlodge wrote:
    Sounds to me you are about a "54cm" frame size. The issue with going to a smaller frame is that you will also get a smaller head tube, which means the drop from saddle to bars will be even greater. I would seek some expert bike fit advice otherwise you risk making a big mistake.

    Do you feel simply too stretched out, or too much weight on your hands?

    ^Yeah, these are the points you need to consider. I've owned bikes that have been both too long and too short for me and they each present different issues.

    I'm not sure I'd recommend a bike fit particularly, but I would suggest you try both size frames prior to buying. The difference between a 54cm and a 51cm frame will mean all kinds of different angles.

    If I had to give an opinion I'd say go 54 with a shorter stem.
  • darkhairedlord
    darkhairedlord Posts: 7,180
    I take it you already have a road bike?
    Does it fit?
    If it does then just look up or measure the geometry and compare with the new one.
    54, 56,58 etc is largely irrelevant.
    The only numbers that mean anything are the stack and reach. Get these close and the rest will dial out with stem length and seat set back.
  • I'm a similar size to yourself and personally I fit around a 54-55cm effective top tube length with 110\120mm stem (so usually 53\54cm seat tube), but with an inline seatpost. I've tried shorter stems but was never really comfortable with stock layback posts, even with saddle to bar distance the same or less than I have now, as my centre of gravity or balance always seemed out.

    This has even allowed me to drop the bar height as my weight isn't going forward as much as it's better supported by the saddle and my legs on the pedals (plus improved core strength), so might be worth a try if it's an option when testing the bike(s) out.
  • duckson
    duckson Posts: 961
    5ft 8.5in, 30.5in inside leg and i have a small (listed as 52cm) Scott CR1 SL.

    ETT is 530mm, 520mm seat tube, seat tube angle is 74.5deg, headtube is 136mm, 110mm stem and 25mm setback post and its perfect for me.
    I had a Boardman Team Carbon in medium which had a 555mm ETT and found it slightly too big a bike for me, 100mm stem on that but seat further forward (73.5 deg seat tube angle).
    Cheers, Stu