Is 54.5 top tube too long for 170cm rider?

nthanach
nthanach Posts: 3
edited May 2019 in Road buying advice
Hi Everyone

I am curious about my torso length, i am 170cm with 80 cm inseam. I have a torso length of 60 cm (this is obtain by subtracting inseam from sternal nothch(140cm). Two of the builders said that I have long torso. I should like the bike with 50-51 cm seat tube and 53.5 to 54.5 top tube.

I am wondering whether the top tube length is too long for my body. I never ride the bike that come with that length of top tube before.

Thank you for your advice

Comments

  • keef66
    keef66 Posts: 13,123
    No substitute for actually sitting on the bikes to see which feels best. A lot depends on the geometry of the bikes.

    FWIW I'm 168cm and similar inseam to you and I have a 51cm winter trainer which has a 54cm top tube and a 54cm summer bike with a 54cm top tube.
  • First.Aspect
    First.Aspect Posts: 17,379
    I'm 8 cm taller than you with a similar inseam, and that's my size, so the answer is "probably" and "see comments above".
  • N0bodyOfTheGoat
    N0bodyOfTheGoat Posts: 6,065
    I'm 178cm with ~83cm cycling inseam, my 58cm framed Cube has a 57.5cm top tube, my 18" framed Voodoo has a 59.5cm effective top tube. Both have 110mm stems.

    But my Cube, like several brands, has a relatively odd frame design. I needed a bigger frame than normal to get "stack" and "reach" figures similar to older bikes, the 58cm has 610/388mm respectively.
    ================
    2020 Voodoo Marasa
    2017 Cube Attain GTC Pro Disc 2016
    2016 Voodoo Wazoo
  • secretsam
    secretsam Posts: 5,120
    Horses for courses. I am 173cm with 75cm inseam, long body, 545mm TT fits me fine (11cm stem). As others say, try one.
    It's just a hill. Get over it.
  • nthanach
    nthanach Posts: 3
    Thank you every one for the comments, the thing is it's a custom bike so I don't have a chance to try it on. I think I will go for it as the builder recommended
  • skyeflyguy
    skyeflyguy Posts: 110
    nthanach wrote:
    Thank you every one for the comments, the thing is it's a custom bike so I don't have a chance to try it on. I think I will go for it as the builder recommended
    Hi I was in the same situation 18 months ago. I am 171 and also slightly longer in the top half according to one bike fitter.
    I had a bike fit by Retul to try and establish or more confirm the geometry for a custom frame that I should go for.
    I based the frame around a Cannondale supersix size 52 geometry which was a 53.5 top tube, and according to Cannondales height chart would put me in the upper end of this size. I was riding with a 100mm stem and with 80mm of bar drop with a inline seat post as advised by the bike fitter. To cut a long story short I was going fairly well on the new bike and decided to get another fit from an independent fitter to get my position spot on.
    His assessment was on the opposite ends of the scale to Retul in a lot of aspects but he suggested that I should be riding on a 520 top tube. Now I am not totally convinced he is right and I have gone to a shorter stem as a trial.
    I think? what I am trying to say is that a 54.5 may be too long for you. Also a good fitter would be an obvious move but unfortunately that didn't work out for me either. Having a custom frame built you just want to get it spot on but that's not as easy as it sounds. Take plenty of time and try some bikes that you think may be the size that you want.
  • badgermat
    badgermat Posts: 10
    Maybe, maybe not.

    I'm 173cm and on a 550mm top tube (378mm reach) frame. It's just a touch of a stretch, but basically okay with a 90mm stem.

    bm
  • part time waster
    part time waster Posts: 244
    I am 177cm tall and a 31cm inside leg. I choose to ride between 53 and 54 top tubes , with between 10 and 13cm stems to get the right feel on race or winter set ups.
    I see lots of bikes with 90 mm stems as supplied off the shelf. These always seem crazy short. Obviously each to their own.
    20 years ago bikes seemed to come with more like 110mm stems off the peg.
    That's how I remember it. Has there been a shift in styling or shape I have missed. Or is my memory burnt out ?
    I never look at reach, stack. I know a 53.5 top tube will always fit me , then just build it up and fit a 11 or 12 cm stem .
    Just bought a Ciocc as above size , soon be on the road.
    Yes I have mixed mm and cm along the way. I was always focused on the smallest frame and longest stem combo for the pro fit and style. Pity I'm a club banger !
  • Hendrix2430
    Hendrix2430 Posts: 119
    Personally I’d have to say 54.5tt is likely to be a bit long for you, if you plan on using a 100+ stem, and have std layback on your saddle.

    You might be incredibly flexible or have super long arms though so it depends.

    To give you an example, I am 171cm, 31 inch inseam, and run a caad12 in 52 (534 tt) with a 100mm stem and tcr in small (535 tt) with a 110mm stem. Arm/leg length balanced, 31” inseam.
  • alanyu
    alanyu Posts: 73
    Don't consider TT, that's actually not that important.

    If you have read something about bike fitting, consider reach, stack and STA, or read some info online.

    One bike with TT 545 can be smaller than another bike with TT 535.

    I have a similar body proportion with you, 170 height, 80 inseam, 141 nothch, 177 winspan. My frame is R 383 and S 531.
  • First.Aspect
    First.Aspect Posts: 17,379
    alanyu wrote:
    Don't consider TT, that's actually not that important.

    If you have read something about bike fitting, consider reach, stack and STA, or read some info online.

    One bike with TT 545 can be smaller than another bike with TT 535.

    I have a similar body proportion with you, 170 height, 80 inseam, 141 nothch, 177 winspan. My frame is R 383 and S 531.
    B0llocks
  • rnath
    rnath Posts: 176
    I’d guess that’s slightly too long. FWIW I’m 170cm with stumpy legs and 52-53cm top tube is right for me. I’ve owned a 54tt bike in the past... worked fine with 90mm stem and not much seatpost, by smaller bikes give me much more flexibility when fitting.
  • alanyu
    alanyu Posts: 73
    First Aspect wrote:
    alanyu wrote:
    Don't consider TT, that's actually not that important.

    If you have read something about bike fitting, consider reach, stack and STA, or read some info online.

    One bike with TT 545 can be smaller than another bike with TT 535.

    I have a similar body proportion with you, 170 height, 80 inseam, 141 nothch, 177 winspan. My frame is R 383 and S 531.
    B0llocks

    Bollocks?
    Nowadays frames have diveristy geometries. It's not the old steel frame age something like that bikes with TT 535 and ST 515 are almost designed with around 100 headtube and around 74 STA. Or you genius know the actual size of the frame which posted by the starter? My dynamic fitter has never suggested any information on TT. Also when I built up my bike, I never consider about TT.
  • keef66
    keef66 Posts: 13,123
    nthanach wrote:
    Thank you every one for the comments, the thing is it's a custom bike so I don't have a chance to try it on. I think I will go for it as the builder recommended

    You're getting a custom frame made without sitting on a sizing jig or sample frames? Basing it all on measuring body parts / what the frame builder thinks / random comments from forum pundits? Braver than me!

    Do you at least already have a bike you're comfortable riding which you can take measurements from?

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