HELP - Bike fit - Top tube / stem length

chris217
chris217 Posts: 218
edited October 2012 in Road buying advice
quick bit of advice needed about bike fit and yes i am going to have a 'proper ' bike fit shortly.

i am 6'2" and a bit...longer torso than legs and usually run a 580 top tube and 120mm stem so 70cm total and all the bike fit calculations i have carried out suggest a 700 to 703 top tube / stem length combined. i also run a 18cm headtube with about 30mm spacers ( integrated headset )

( aware angles make a difference so for the sake of arguement 73 / 73 fork and seat angles )

my issue is i am looking at new frames especially ti and they seem to be either 57cm or 59 top tubes , also some 57.5cm lengths available.

i am thinking about a frame which has options of 57.5 or 59cm top tubes , the headtube measurements are fine for both but probably prefer the 59cm frame which has a 1cm larger headtube

the question is i am aware while i currently run a 120mm stem but assuming with a 57cm top tube i would simply increase the stem length to compensate to 130mm ... and conversly if i was to go for a 59cm top tube then i would reduce the elngth to 110mm right ?

i am aware there may be a small affect to handling i.e. speed up and slow down steering

would be intereseted to hear from anyone who has ' played around with geometry' and adjusted stem length to ensure a proper fit or is the consensus this should be an exact science ?

comments appreciated cheers

Comments

  • That should work okay.

    If it was an exact science then stems would need to come in closer sizes than 1cm.

    The way I get my 3 road bikes to the same(ish) fit is to measure from the front tip of the saddle to the centre of where the bars fit into the stem. Minor adjustments are made by flipping the stem or removing spacers.
  • greentea
    greentea Posts: 180
    Ive played around with stem and seat position. From my experience ive found sizing down the frame (if its not my exact size) to be better than going up a frame size, as ive found it easier to gain extra length rather than shorten it, but thats just me. My upper torso is longer than my legs even though im 6ft 2.

    Stem options seemed to be easier to extend rather than shorten and seat postion i found i could get extra length backwards with offset seatposts as well as moving the seat on the rails.

    I bought a frame one up from what i normally have (normally a 58) and i just found it harder to shorten everything to squeeze it up a bit than i did on a shorter frame where i could extend thing out. I was always aware with the longer top tube that it was longer and that even with a shorter stem and the seat moved forward that i was arching over it, if that makes sense.

    But as i say, its always each to their own!
  • Mccaria
    Mccaria Posts: 869
    I am also 6'2 and tend to prefer a 58cm TT with a 12cm stem where possible.

    When I was getting a Canyon I tried a 62cm frame which has a 59cm TT and a 60cm frame with a 57.5cm TT, I tried the 62cm frame with an 11 cm stem and the 60cm frame with a 12cm stem. Much preferred the 57.5cm TT, no discernible difference to the 58cm TT, whilst the 59cm TT felt too long for me and didn't look/feel right with the shorter 11cm stem. I have another bike which has a 57.5cm TT which I also ride with a 12cm stem, did try it with a 13cm stem but the 12cm stem felt better. So as above would tend to favour going for the slightly shorter TT and compensating with a longer stem if required.