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Bike sizing

NameTakenNameTaken Posts: 45
edited June 2016 in Road beginners
I think my bike is too big for me, so I've been doing some reading around bike sizing and fit and I wonder if I'm missing something.

I'm 6'3" and a bit and the bike is a 61cm Felt F95. I am approaching 50, 107kg, large build (I don't look fat even at that weight).
I've put a shorter stem on and moved the seat forwards but still feel that I'm stretching too far. To bring the handlebars back to a comfortable position I think even the shortest possible stem would be borderline.

I'm thinking about buying another frame and wondering about sizing. One size down would be a 58cm, but a couple of cm variation in the length of the bike is nothing and doesn't compensate for the shorter stem.

What do I need to be aware of - what are the issues with too small a frame?

Frame sizes for a given bike are typically 2 or 3 cm apart and I see people having long discussions about what size to get, but I'm struggling to see that the difference between one size and the next is that much of an issue. With the amount of adjustment on a bike, especially once you include stem swaps it looks as if the adjustment on an individual frame is way more than the difference between 2 or 3 frame sizes.

As I see it you have the three important points, crank, seat and handlebar.
The crank is the starting point and other than changing lengths of the arms that is fixed.
You can adjust the seat up and down by quite substantial amount, move it back and forward in a range of a couple of inches - the bike size doesn't seem have much impact on this.
The handlebars can be moved in a reasonable range by swapping the stem and varying spacers - I can see that the fork steerer length would be a limiting factor, but stem selection gives a massive variation in handlebar position.


  • kajjalkajjal Posts: 3,380
    The saddle position is to get your legs in the right position, as tempting as it is don't move it to adjust reach !

    Reach is adjusted by bars and stem sizing. A quick test is if you had the choice where on your existing bars do your hands naturally fall. If you lean forwards slightly you should be on the hoods and lean back upright a little you should be on the bar.

    My old bikes bars had a long reach and long drop to the drops. My new bike has bars that are shallow drop and over an inch less reach. Apart from that the bikes are very similar. I am now much more comfortable and can ride in the drops for long periods which never happened before.

    If you have a long drop from the saddle to the bars flipping the stem into the upright position raises the bars and also reduces reach.
  • NameTakenNameTaken Posts: 45
    Yep, take that all on board, thanks.

    I suppose my point is that it seems to me that bike sizing for recommended heights is a load of bollocks :)
    Probably some of that is down to the frame shapes of modern bikes and the lengths of seatpost meaning that the traditional sizing mechanism of crank to top of seattube is an irrelevant measure. I think that the most important measurement is the effective top tube length.

    I suppose this is old news to people on here but as a noob it is a revelation.

    At 6'3" I'm more comfortable on my teenage daughters bike (a size small planetX rt-58) than I am on one that is supposed to fit my height(albeit with the seat at its maximum height) and the factor that influences the comfort is the reach.

    I need to go frame shopping.
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