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  1. #1
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    True advantage of lower seatstays ?

    So what is the deal about it ( BMC,2018 Tarmac ) ? Do they make the bike stiffer or just more comfortable ? I still donít get it...

  2. #2
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    It makes the bike look different.

    If all bikes were made of the exact same tubing we could talk about what lowering the stays might do to the ride. But with carbon bikes you can make up for just about any shape by altering the layup.
    Get a better saddle: www.kontactbike.com

  3. #3
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    It's about aerodynamics. Could also play a part in some comfort, but it came about due to aerodynamics. Most every TT bike has that design now and they were the first category to really push into it.

    I don't think stiffness has anything at all to do with it. And comfort is very minor if anything. Makes fitting fenders like the Crud MK3 a real pain.
    use a torque wrench

  4. #4
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    Quote Originally Posted by MMsRepBike View Post
    It's about aerodynamics. Could also play a part in some comfort, but it came about due to aerodynamics. Most every TT bike has that design now and they were the first category to really push into it.

    I don't think stiffness has anything at all to do with it. And comfort is very minor if anything. Makes fitting fenders like the Crud MK3 a real pain.
    This bike was neither comfortable nor aero:

    Get a better saddle: www.kontactbike.com

  5. #5
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    Quote Originally Posted by Kontact View Post
    This bike was neither comfortable nor aero:
    The question is what's the true advantage of lower seat stays.

    The answer is aerodynamics.

    You may think they're only there to look different, it seems that's what you're saying. But my answer is correct.
    use a torque wrench

  6. #6
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    Quote Originally Posted by MMsRepBike View Post
    The question is what's the true advantage of lower seat stays.

    The answer is aerodynamics.

    You may think they're only there to look different, it seems that's what you're saying. But my answer is correct.
    I'm saying that there are any number of reasons that a bike might be designed with lower seat stays, and only some of them are for aerodynamics - if the frame actually ends up being any more aero at all. The rest are largely aesthetic.
    Get a better saddle: www.kontactbike.com

  7. #7
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    I donít see much or any ďtrueĒ advantage. But like everything else if not done right it can look really ugly...

    https://youtu.be/ttDAm52pUCc


    Sent from my iPhone using Tapatalk

  8. #8
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    Quote Originally Posted by Devastazione View Post
    So what is the deal about it ( BMC,2018 Tarmac ) ? Do they make the bike stiffer or just more comfortable ? I still donít get it...
    It's a clear, visible indication that the bike was built with PFM (pure effing magic) technology. Otherwise, how would you know?

  9. #9
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    1. Aero
    2. Smaller triangles are technically stiffer
    3. To be different (biggest reason imo)


    Quote Originally Posted by Drone 5200 View Post
    I donít see much or any ďtrueĒ advantage. But like everything else if not done right it can look really ugly...
    https://youtu.be/ttDAm52pUCc
    That's a CX bike and they have done it because that shape is more comfortable when carrying the bike over one's shoulder. It's not ugly, it's just function over form.

  10. #10
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    I always assumed it was for weightweenieism. you said "low" but some would say "short" and naturally less length means less weight.

    What's the advantage of higher ones? Do you 'get' that? I'm not really asking, just trying to make the point it doesn't matter to who cares.

  11. #11
    JSR
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    The Specialized Roubaix seat stays are short and offset from the junction with the top tube. They claim to have a stiff rear triangle with a compliant seat tube/post setup. Itís pretty nifty, IMO.

  12. #12
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    Another question : some guy on another forum said they supposedly make the bike bad at climbing.....say what ????

  13. #13
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    Quote Originally Posted by Kontact View Post
    I'm saying that there are any number of reasons that a bike might be designed with lower seat stays, and only some of them are for aerodynamics - if the frame actually ends up being any more aero at all. The rest are largely aesthetic.
    Exactly so, as for Aero's, the Head Tube/Forks "cleave" the high pressure buildup, along with the handlebars and your body, once the leading edge "penetrates", the rest follows along in lower pressure "dirty air"..

    so theoretically lower stays present less surface area due to a lower angle of attack, and the fact that shorter stays present less "wetted area".

    of course the draggiest thing on your bike is your own clothing and body, and helmets can be particularly draggy as well.

    How much this all matters depends of course on your speed, drag rising "exponentially" as speed increases..

    So in the grand scheme of things, seat stays are rather inconsequential, but the aesthetics and product "branding", now that's what really sells bicycles..

    I'm still rather "enamored" of the "hourglass stays" on my old Cannondale R700, Heh?

    and the best of all, looking down at that "Made in USA" sticker right behind the head tube??

  14. #14
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    Cool

    Quote Originally Posted by K4m1k4z3 View Post
    1. Aero
    2. Smaller triangles are technically stiffer
    3. To be different (biggest reason imo)



    That's a CX bike and they have done it because that shape is more comfortable when carrying the bike over one's shoulder. It's not ugly, it's just function over form.
    While we likely will all agree with 1 and 3,,,, technically larger triangles, lugs, tubes and drop-outs being the same are more stiff, and resist the bending moment of vertical forces acting on the rear tire with more authority...

    and that top tube, seat tube juncture, while allowing the seat tube more "compliance", is also lacking in the "style" department, but that of course in not measurable and is subjective...

  15. #15
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    Quote Originally Posted by JSR View Post
    The Specialized Roubaix seat stays are short and offset from the junction with the top tube. They claim to have a stiff rear triangle with a compliant seat tube/post setup. Itís pretty nifty, IMO.
    The relatively lower, up seat stay attach point on the seat tube, should technically allow the rear tire greater vertical and lateral compliance, in addition to allowing greater compliance in the upper seat tube. I do like the appearance of Specialized frame, and I should say that I found BMCs lower attach point of seat stays to be very attractive, or maybe just "different"?

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