stuck between frame sizes -- advice needed

Discussion in 'Cycling Equipment' started by tiogapass, Aug 30, 2004.

  1. tiogapass

    tiogapass New Member

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    i'm shopping for a new bike and am stuck between 54cm and 56cm. well, i'm not stuck but the bike shop is trying to convince me i'm not a 56cm rider. i'm about 5'8", 31" inseam. my 12 year old bianchi is a 56cm. i've done 2 cross-country tours and have about 7500 miles on it. fits great, though by most calculations i should probably be riding a 54, correct? what i really love about the bianchi is the leverage i have on hills when out of the saddle and am pulling on the hoods. i'll be doing a lot of riding in the mountains so maintaining the same leverage is of utmost importance to me. i might do some touring on the new bike, but want to enter a few races, too. the local bike shop is adamant about me being a perfect 54 but i test rode a trek 5200 54cm and it just didn't seem to climb with the same efficiency as my old bianchi, though it felt okay -- a little small -- when in the saddle. i attribute the difference in climbing efficiency to the size; the bianchi has a reach about an inch longer than the trek; on the trek, i felt i had to move back to get the same leverage when out of the saddle, which felt unnatural and required more effort. so, go with the bike shop's rec. or defy the experts and go with the size i'm used to and feels right? i realize frame fits are going to vary according to geometry, etc. i also rode a 55cm klein aura x and it felt good when out of the saddle but they tried to tell me i need a 52 in the klein.:confused:
     
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  2. sorebutt

    sorebutt New Member

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    Go with the smaller frame.. when a bike is a bit too small, you can play with the seat position (up/down, fore/aft, angle), and the stem/handlebar position (higher lower, closer further) etc.
    If the frame is too big, you will need a hacksaw.. :)
    I am making this recommendation from experience. I was between 2 sizes, and went with the bigger bike. I hated the bike for the 4 years I rode it. there was nothing I could do to get comfortable on it..
     
  3. TechJD

    TechJD New Member

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    my suggestion is have the bike shop raise the seat about 2 cm on the trek 5200 54cm and then move it backward about a 1/2 inch and see how that feels
    if you still dont like it go with the 56cm
     
  4. nutbag

    nutbag New Member

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    In my opinion, the critical measurements are the top-tube and the head-tube.

    The seat post provides plenty of scope to move up and down several centimetres, but you've only got a few cm to play with regarding head-stem length, and if the head-tube is too short, there's only so high you can go with spacers to get the bars up high enough.

    I'm speaking from (a bad) experience. I bought a steel 58cm frame recently, and did'nt even bother to measure the head tube -- I just thought it would be the same as my aluminium 58cm frames, but NO. I forgot about the larger tubes resulting in the alu frame having a 185mm head-tube, but the thinner steel tubes, and the fact that it was lugless, mean that the head-tube can be much smaller -- it was 162mm!!

    So, I didn't figure it out until I was hammering down Beach Road (Melbourne)with my back in agony because I was bending over so far. Then I get home and figure I can just raise the bars, but NO, it's already at the maximum height. :(

    So, I'd be measuring the top-tubes and head-tubes of your Bianchi and the new bike, and asking people what the implications are.
     
  5. davidbod

    davidbod New Member

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    If you already have a bike that you like the fit of then measure it and compare how these measurements would fit on the 54 and 56 frames. The measurements you want to make are the seat height and seat fore aft position relative to the BB, the distance from seat to bar (this is really your overall reach) and the bar height compared to the seat height. After you dial in the seat and bar on the 54 there are a few things you should watch out for. First to get the seat fore aft positioning where you want it, do you have to push the seat so far back that you run out of seat rail room. Second to get the bar height where you want it how much steerer tube has to stick out of the top of the headset. Third to get the reach to the bar correct to you have to go with an absurd stem length. On the 56 you would need to look at these 3 as well. When dialed in I would go with the one which put the seat nearest the center of the seat rails, which comes closest to a 10 cm stem length and allowing no more than 1.5 inches of steerer tube sticking out of the top of the headset. If the 54 can do this then a smaller frame will be better for a more race like position. If the 56 can do this just as well, it would be better for a more overall comfortable touring ride.
     
  6. boudreaux

    boudreaux New Member

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    Yeah, especialy when comparing Treks and Bianchis,as they measure so differently with respect to'nominal size'.
     
  7. TechJD

    TechJD New Member

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    ok so maybe I didnt say it quite right but basicly have it roughly fited and see
    how it feels
    I'm just thinking that hes not goin to know for sure unless they make
    some changes on then to see how they feel right
     
  8. tiogapass

    tiogapass New Member

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    thanks for all the responses and advice. i finally decided on a 56cm klein and i've only had a chance to ride it once other than the short test rides, but i can tell a major difference in feel and efficiency from the 54 -- at least in my head :). and physiologically, too. instead of pedaling with my knees i could feel some burn in the upper part of my thigh -- hallelujah. i actually had already purchased the 54 but the shop worked with me -- kudos to the shop owner and staff! the 54 was excruciatingly uncomfortable and restrictive out of the saddle. i rode the 54 one last time on a 40-miler with some hill repeats and it put tremendous pressure on my abomen because i was bent over so far out of the saddle (has anyone ever heard of a hemorrhoid from bicycling?). it was like trying to run a sprint bent over at the waist. not efficient or comfortable. i don't really understand why i feel better on the 56 because i measured well on the 54 and i'm only 5'8". maybe it was all psychological but i climbed the same hill on the larger klein out of the saddle without any discomfort and at a speed of around 3mph faster than on the 54. a good feeling, to say the least. the one thing i learned from this whole 2-3 week experience was to ride enough bikes and sizes to make a good decision about what feels comfortable and efficient. not very scientific but i'm happy with the ultimate outcome. thanks again.
     
  9. nutbag

    nutbag New Member

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    There's gazillion different measurements that could've made the smaller bike uncomfortable, but it's good you got it sorted out.
     
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