Hybrid bikes - effective top tube length

RobinB2
RobinB2 Posts: 111
edited November 2016 in Road buying advice
I'm looking at buying a hybrid bike for my teenage son who is about the same height and build as myself (ok - he's a lot thinner) but am slightly confused by typical hybrid bike dimensions

I have generally found that the most useful guide to finding a road bike that fits me is to look for an effective top tube length of approx 54.5 cm and a head tube of at least 140mm, which usually equates to a Medium frame size

However, typical hybrid bike geometries I have looked at have Medium frames with effective top tube lengths in the region of 58 - 59 cm

Am I missing something or are hybrid bikes just sized differently?

Comments

  • bondurant
    bondurant Posts: 858
    Because they don't have drops?
  • apreading
    apreading Posts: 4,535
    Bondurant wrote:
    Because they don't have drops?

    ^ this

    Your road bike is set up for ideal body position when in either the hoods or the drops. If you actully hold the flat part of the bar near the stem, your hands are therefore too close to the saddle. To counter this without a stupidly long stem, flat bar bikes have a longer top tube.

    Thats why converting a drop bar bike to flats or vice versa isnt really as simple as it might seem at first...
  • RobinB2
    RobinB2 Posts: 111
    Thanks - makes sense - I couldn't work out why some hybrid geometries (top tube and headset length) would represent a fairly radical racing bike geometry

    I rarely use the drops but can work out what the effect of taking the additional distance to the hoods into account would be

    Thanks again

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