Cervelo Dual 54cm Triathlon / Road Bike Frameset w/ Seat Post & Headset
세르벨로 듀얼 54cm 트라이애슬론 / 로드 바이크 프레임셋(시트 포스트 및 헤드셋 포함)
| 상품번호 | 137287194642 |
| 상태 | New other (see details) |
| 거래유형 | 즉시구매 |
| 출고국 | 미국 (US) |
이베이 판매가
$550.95
약 812,100원
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상품 설명
Cervelo Dual 54cm Triathlon / Road Bike Frameset w/ Seat Post & Headset
To optimize aerodynamics, the tubes need to have a very specific shape, a profile determined by the National Advisory Committee on Aeronautics (NACA). This shape can only be obtained by extruding the tubes, as forming round tubes imposes too many shape limitations. As an example, a round tube has about 5 times the drag of a NACA-profile, while a crushed tube is about 3 times as bad. A very important part of the shape is its thickness-to-chord ratio. If this ratio is high (meaning the tube is relatively wide compared to its depth), the air flow will detach, creating turbulence and high drag.
It is also important to note that the correct NACA profile is not round at the front but elliptical. Aero tubes with a round front and sharp trailing edge are becoming more and more popular (because it they are easy to make out of a round tube, and because they will easily take a round seat post if used as a seat tube). But unfortunately, they offer hardly any aero benefit, as the bluntness of the round front already deflects the airflow before it reaches the trailing edge.
Which wheel size is faster depends on how big you are and the position you ride in. It all comes down to putting the rider in a comfortable and aerodynamic position and designing the bike around that.
Rider Position: If the rider rides in an aero position, the handlebars and aerobars will usually be in a relatively low position, lower than on a road bike. In a small frame size, this low position of the bars can conflict with the size of a 700c front wheel, as the big wheel and the low bars wouldn't leave enough room for a headtube. Hence for small sizes we recommend 650c wheels. For larger sizes, a good position can be obtained over either a 650c or 700c front wheel, provided that in both cases the headtube is kept short enough (shorter than on a road bike of the same size).
Bike Aerodynamics: Since both wheel sizes will work on bigger frames, the optimal frame will be the one with the lowest drag. While a 650c wheel has slightly less drag and uses a slightly more aero fork (shorter fork legs), a 650c frame will have a 2" longer headtube, assuming an identical aerobar position. Our wind tunnel testing shows that due to that shorter headtube, a 700c bike will actually be slightly more aero than a 650c bike. Therefore, for the larger sizes we recommend 700c wheels, but for mid sizes the customers' current equipment and other factors will also enter into the equation.
New Old Stock - Brand New & has never been built up. See Pictures.
I will ship this in the original frame box from Cervelo.
Cervélo Dual Aluminum aero frame with Aluminum Seat post & Carbon Fork.
- Cervélo Smartwall 2 tubing with Full TrueAero frame and aero seat post
- ICS (Internal Cable Stops), the best internal cable system available
- 650c/700c wheel size optimized per frame size
- Adjustable geometry with 74–79-degree seat tube angle range
- UCI legal
- Aero seat tube
- Aero seat post
- Ultegra components
- Adjustable geometry
- Integrated headset
To optimize aerodynamics, the tubes need to have a very specific shape, a profile determined by the National Advisory Committee on Aeronautics (NACA). This shape can only be obtained by extruding the tubes, as forming round tubes imposes too many shape limitations. As an example, a round tube has about 5 times the drag of a NACA-profile, while a crushed tube is about 3 times as bad. A very important part of the shape is its thickness-to-chord ratio. If this ratio is high (meaning the tube is relatively wide compared to its depth), the air flow will detach, creating turbulence and high drag.
It is also important to note that the correct NACA profile is not round at the front but elliptical. Aero tubes with a round front and sharp trailing edge are becoming more and more popular (because it they are easy to make out of a round tube, and because they will easily take a round seat post if used as a seat tube). But unfortunately, they offer hardly any aero benefit, as the bluntness of the round front already deflects the airflow before it reaches the trailing edge.
Which wheel size is faster depends on how big you are and the position you ride in. It all comes down to putting the rider in a comfortable and aerodynamic position and designing the bike around that.
Rider Position: If the rider rides in an aero position, the handlebars and aerobars will usually be in a relatively low position, lower than on a road bike. In a small frame size, this low position of the bars can conflict with the size of a 700c front wheel, as the big wheel and the low bars wouldn't leave enough room for a headtube. Hence for small sizes we recommend 650c wheels. For larger sizes, a good position can be obtained over either a 650c or 700c front wheel, provided that in both cases the headtube is kept short enough (shorter than on a road bike of the same size).
Bike Aerodynamics: Since both wheel sizes will work on bigger frames, the optimal frame will be the one with the lowest drag. While a 650c wheel has slightly less drag and uses a slightly more aero fork (shorter fork legs), a 650c frame will have a 2" longer headtube, assuming an identical aerobar position. Our wind tunnel testing shows that due to that shorter headtube, a 700c bike will actually be slightly more aero than a 650c bike. Therefore, for the larger sizes we recommend 700c wheels, but for mid sizes the customers' current equipment and other factors will also enter into the equation.