Understanding Frame Geometry-Help

Avit5
Avit5 Posts: 114
edited April 2013 in Road buying advice
Can someone with more knowledge and understanding please try and help me understand the 2 different frame measurements from these 2 bikes:

........................... Bike A........... Bike B
Frame size.............. 60............. 61
Seat tube length.... 595.......... 610
Top tube length..... 583......... 580
Head tube length.... 190........ 190
Chainstay length.... 410........ 409
Wheel base.......... 1014........ 989
Stack.................... 598........ 599
Reach..... ............ 405........ 401

I am aimimg for a more relaxed riding position rather than racing position. So based on the above measurements would the seat tube length of 610 on Bike B mean that there is less of a drop from saddle to handle bars because I would not need the seat raised so high thus meaning a more upright position ?
I know the standard answer will be to try both bikes but this is not possible as they are internet order only.
If you think I am totally barking up the wrong tree with these frame measurements for my desired riding position then please say. I know there are plenty of bikes with longer head tube lengths but just looking for peoples opinions on these 2 for know.

Comments

  • bernithebiker
    bernithebiker Posts: 4,148
    I would say Bike A is the more relaxed 'Sportive' type and Bike B the more sporty, racier type, but hard to say without having a closer look.
  • Avit5
    Avit5 Posts: 114
    bernithebiker wrote:
    I would say Bike A is the more relaxed 'Sportive' type and Bike B the more sporty, racier type, but hard to say without having a closer look.
    Does the seat tube length then being longer on bike b not make much difference? I thought this would mean less seat post showing and less of a drop to the bars . On bikes that I have tried in the shops because of my long legs (91cm inseam) compared to my height of only 184 cm the seat needed to be raised so much that it felt like all my weight was going through my arms because of the steep angle of drop from seat to bars.
  • lc1981
    lc1981 Posts: 820
    edited April 2013
    Avit5 wrote:
    So based on the above measurements would the seat tube length of 610 on Bike B mean that there is less of a drop from saddle to handle bars because I would not need the seat raised so high thus meaning a more upright position ?

    The seat might be raised more relative to the top of the seat tube, but surely not in absolute terms? By the looks of it, the top tube on bike A is more sloping, but that's not going to have an impact on the height of the saddle - it just means that more seatpost will be showing to achieve a given height.
  • schweiz
    schweiz Posts: 1,644
    Avit5 wrote:
    So based on the above measurements would the seat tube length of 610 on Bike B mean that there is less of a drop from saddle to handle bars because I would not need the seat raised so high thus meaning a more upright position ?

    No, assuming crank length and BB drop are the same, you'd just have less seat post out of the frame to set your saddle height. Once on the bike it's the distance between the saddle and the pedals relative to you leg length that you're adjusting. The head tube length is the same so again assuming the same stack height of the stem and the bearings, the drop will be identical from your saddle.
    VN BMC Cube SS
    http://app.strava.com/athletes/30000
  • flasher
    flasher Posts: 1,734
    Head tube and seat tube angles are an important part of the equation.
  • schweiz
    schweiz Posts: 1,644
    Flasher wrote:
    Head tube and seat tube angles are an important part of the equation.

    I meant to write that too!
    VN BMC Cube SS
    http://app.strava.com/athletes/30000
  • Avit5
    Avit5 Posts: 114
    I only have the bike a measurements for head tube angle - 73.25 and seat tube angle - 73.5.
  • Avit5
    Avit5 Posts: 114
    So from the information so far then I need to either find a bike with a longer HT or just MTFU and get used to a lower position. (My current bike has a HT of 20cm but when I tried one with a HT of 19cm it seemed such a difference and much lower. Wouldn't have thought that 1cm would make that much difference but it did.)
  • schweiz
    schweiz Posts: 1,644
    Longer head tube and/or a stack of spacers under the stem and/or flip the stem.
    VN BMC Cube SS
    http://app.strava.com/athletes/30000
  • Cheshire Cat
    Cheshire Cat Posts: 309
    Something else to consider, just by looking at the figures you give, is that the wheelbase on bike 'B' is much shorter, giving you a sharper handling bike, but that will also be dependent on the fork rake, which isn't given - meaning if you want a relaxing ride 'A' would be the better option.
    “Faster, Faster, until the thrill of speed overcomes the fear of death.” Hunter S Thompson

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