How does head tube length alter bike fit ,choosing a bike

cyberknight Posts: 1,238
edited May 2011 in Road buying advice
I am currently in the process of narrowing down my choices for bikes i am considering getting on C2W and i have a question on how head tube length affects bike fit.

My current bike a virtuoso
has a head tube of 15 cm, effective top tube of 54 cm and a virtual seat post of 54cm (50 real )

The bike i am considering a boardman
has a head tube of 13.5 cm, effective top tube of 54cm and a seat tube of 51.5 cm ( no virtual listed )

How much will the 1.5 cm difference make? maybe it does not as the seat tube is longer?, and if it is a big issue could it be overcome by stem flipping if the saddle-> handlebar drop is to much?

The alternative would be to go for a trek 1.2
with head tube of 15cm, effective top tube of 54 cm and a seat tube of 50.6 ( no virtual listed )

It needs to be a bike in can get on C2W through Halfords and £700 was what the ballpark i wanted to spend.
FCN 3/5/9


  • Headtube length makes a significant difference to a bike - the longer the headtube (relative to top/seat tube) the more upright the riding position.

    Can you not take a few of your choices for a spin and see what works for you?
    Never mistake motion for action
    Trainerroad - GMan69
  • cyberknight
    cyberknight Posts: 1,238

    Can you not take a few of your choices for a spin and see what works for you?

    Living in the sticks getting a test ride is very hard to do , the LBS around here do not stock them, what they do have i cannot get through C2W .as we have to use Halfords, who do not even stock the small Boardman unless you order one in.
    FCN 3/5/9
  • graham_g
    graham_g Posts: 652
    You don't let a bike dictate your position - that is all down to your own physical dimensions and other factors such as flexibility etc. All a shorter head tube is likely to mean is that you'll need more or fewer headtube spacers to attain your ideal position. If, like me, your dimensions dictate a high bar position then a small headtube is going to leave you with a large stack of spacers, which isn't a problem unless you're using all carbon forks which allegedly shouldn't be used with more than 40mm of spacers due to the extra stresses on the steerer. Alloy/steel - fill yer boots, but it might end up looking like a thorn and your headset takes a little extra strain.
  • Bobbinogs
    Bobbinogs Posts: 4,841
    Yepp, you could also flip your stem to get some extra height if needed even if just to see whether it is the right overall height or not. It just looks wrong though, IMO. :)
  • I think (FWIW) if you have much more than 30mm of spacers on a steerer, you would have to question whether the bike fits you.
    Never mistake motion for action
    Trainerroad - GMan69
  • night_porter
    night_porter Posts: 888
    To ascertain whether the Boardman would be suitable just remove 2 spacers from below your current bar and ride it for a week or two.

    Obviously if you have a 5mm spacer then take the 15mm out and put it above the bar.

    Having a lower bar shouldn't really make that much difference to someone who is reasonably fit with no back problems.

    However, it will take a couple of weeks riding to know whether it is for you or not.

    If it is a problem you could flip the stem or use an adjustable stem to raise the bar.

    You could even lower your current bar then flip it to see what it would be like too!