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Sizing for Newbie

del420tdel420t Posts: 8
edited February 2009 in Road beginners
Hi Guys

I am looking to buy a bike for around 500gbp. This is my first road bike but it seems like an absolute mine field. I am 6ft 3 with a 37 inside leg. I put all my measurements in an online sizing chart and the results are as follows.

Seat tube range c-c: 62.1 - 62.6
Seat tube range c-t: 64.0 - 64.5
Top tube length: 60.4 - 60.8
Stem Length: 11.7 - 12.3
BB-Saddle Position: 88.8 - 90.8
Saddle-Handlebar: 61.6 - 62.2
Saddle Setback: 7.6 - 8.0


http://www.competitivecyclist.com/za/CCY?PAGE=FIT_CALCULATOR_INTRO

I am now finding it very hard to find an appropriate frame size. I have been reading that the top bar is most important dimension? is this true? Can anyone advise me if there is a site that I can search by frame size or do I just have to troll through manufacturers websites and then look at bikes.

Any advice?

Thanks Del

Posts

  • SupergooseSupergoose Posts: 1,089
    Frame sizing is a minefield!

    Its very much an individual thing as we are all different. The fit systems are handy in that they give you a ballpark figure.

    I think, personally with the popularity of compact frames, the top tube length is the most important measurement.

    If you are new to cycling and particularly because of the physiological measurements you have given, I would advise you to seek out a local bike shop and ask for their advice.

    Good luck! :)
    Rock 'n' Roule
  • colintcolint Posts: 1,707
    Top tube is definitely the most important measurement, make sure you look for effective top tube on sloping frames, not actual. I'm 6'3" and ride a 59cm top tube, but as has been said you really must go to a shop, we all have different leg, torso, arm lengths etc so what suits one wont suit another. Even if your local shop doesnt have the brand you want, go and sit on a few anyway to get an idea
    Planet X N2A
    Trek Cobia 29er
  • Regarding riding position - how do you get a feel for it when you are sitting in a shop - As this is the first bike I don't know if it will be comfortable after an hour in the saddle. Is there a rule of thumb? any advise you can give. I read that your leg should be a right angles when your foot is at the 3pm position.. Is there anything else to consider?

    I will defo go to the shop and try different bikes - it is a shame Boardman are not stocked in my local Dublin Halfords store as they have good reviews and I would like to try it out.
  • colintcolint Posts: 1,707
    Forget about leg position, saddle height for now, thats easy to sort once you've got the right frame size through adjusting the seat post.

    It's going to be difficult to get a good idea of comfort if this is your first road bike as they'll probably all feel a bit weird. You'll probably feel a bit stretched, the key to comfort on a road bike is making sure you're not too stretched, and not too cramped, which is why top tube length is crucial.

    Some shops will offer you a test ride, which is nthe best way too tell. Everyone goes through a learning curve when starting, and it's only after a few hours on the bike, or even months, that you start to realise that an inch higher here or lower there will make you feel better.

    If you get torn between 2 sizes, go for the smaller one as you can always add longer stem etc if you need to
    Planet X N2A
    Trek Cobia 29er
  • I thought the concensus was that if you are between frame sizes you should go for the larger size. The logic being that the head tube will be higher so you should be in a more upright position and more comfortable.
  • del420t wrote:
    Regarding riding position - how do you get a feel for it when you are sitting in a shop - As this is the first bike I don't know if it will be comfortable after an hour in the saddle. Is there a rule of thumb? any advise you can give. I read that your leg should be a right angles when your foot is at the 3pm position.. Is there anything else to consider?

    I will defo go to the shop and try different bikes - it is a shame Boardman are not stocked in my local Dublin Halfords store as they have good reviews and I would like to try it out.

    I'm currently waiting for a Giant Defy 1 and I ordered purely because the shop fitted me to the bike, whereas all the other dealers went "Oh, you're about 5'11" so you'll want a XX cm frame".

    The Giant dealer put a M/L on a turbo, sat me on and adjusted the seat height until my foot was level at the furthest point from the saddle (crank in line with the seat tube). He then adjusted the front-to-back position of the seat until, with the crank at 3 o'clock, a plumb line from the back of my knee-cap fell onto the ball of my foot. He then looked at my position on the bike and said "No, we would need to put too short a stem on it to get you to fit on this one" so he went and got a M, transferred the seat position and got me to slightly pull my hands back from the hoods before fitting a 10mm shorter stem. The result felt very comfy and when, a week or so later, I test rode the bike, I rode an 18 mile route and finished feeling pretty much as comfortable as when I had started - despite not having ridden a drop bar bike for about 20 years.

    The point is, for a noob like me, the fit depends on so many factors - arm length, leg length, back length, flexibility, ... - that it is difficult to assess the correct size without some professional help. I am also convinced that, if you are in between two sizes, one will likely be fine but the other may well not be - and you can't guess which is which without significant experience.

    HTH,

    _
  • Mister WMister W Posts: 791
    wyattlad wrote:
    I thought the concensus was that if you are between frame sizes you should go for the larger size. The logic being that the head tube will be higher so you should be in a more upright position and more comfortable.

    No, you should go for the smaller size and use a longer stem. If you want the bars higher just cut (or get the shop to cut) the steerer a bit longer. You then have the option of lowering the bars if you find a lower position suits you as you get used to the bike.
  • giant_mangiant_man Posts: 6,878
    I don't personally trust online calculations for fitting. And you're right - it can be a minefield. The best thing is to get yourself measured properly by a good dealer. You can then come away with the measurements and you have a permanent record of your sizing for future bikes.

    Then, as colint has said, a test ride of the chosen bike would be good. Too many dealers imo have the 'oh your so high so a L should fit' attitude.

    The worst thing is to get a bike which doesn't fit you. In this respect this is THE most important thing.
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