Jenesuispasungenie a écrit :Quel est ton poids ?
La question peut paraître surprenante, en fait j'ai eu l'occasion de voir des triathlètes sur ce genre d'engin et ceux-ci n'étaient pas forcément des plus sveltes...
Je ne te permet pas !!! Et en plus je suis revenu à mon poids de forme.
Je suis à 75kgs pour 1,88. Donc pas un gabarit de grimpeur, mais pas non plus la grosse Bertha.
Jenesuispasungenie a écrit :...Le tube "horizontal" support de selle a tendance à osciller au rythme de la fréquence de pédalage et l'oscillation est d'autant plus conséquente que le cycliste est lourd. J'imagine alors la perte de rendement à chaque tour de pédalier !
C'est le genre de matériel qui est certainement très bien pour un cycliste au pédalage fluide et qui tourne "rond".
...
Certes ça bouge toujours un peu. De là à quantifier une perte de rendement en secondes...
Le problème est le même que pour un TS en VTT. Il est vrai que les premiers tours de pédales sont déroutants, cette sensation disparait d'autant plus vite que ton pédalage est souple.
Jenesuispasungenie a écrit :...Par contre, en terme de rigidité sur un axe vertical ce n'est peut-être pas le plus efficace, si ça l'était d'autres fabriquants de cycle l'auraient adopté. Mécaniquement un triangle tubulaire a fait ses preuves et pas seulement en cyclisme.
Et ? Que tu t'intéroges sur les pertes de rendement par un manque de rigidité du triangle arrière, certes, mais là...
Qu'un principe soit interdit par l'UCI, et en plus pas rentable économiquement ne présume en rien de sa valeur.
FanchM a écrit :C'est lourd, c'est moche, ca ressemble a une balancoire. Y-a-t-il reellement autre chose a ajouter?
Ce n'est pas le plus léger du marché, on va dire que bien équipé, ça pèse environ un bidon de plus...ou une moitié de bouée abdominale qu'un vélo "à la mode".
Pour le reste...
Personnelement, j'en ai toujours voulu un, j'en ai un, et je ne veut plus rien d'autre. Pourquoi ? Demande plutôt à mon psy qu'à mon biomécanicien.
Maintenant du côté des avantages, regardes en dessous. Je vois déjà Francois dire "labo pas indépendant, observations sous conditions précises, valeurs des gains cumulées ..." c'est certainement vrai. Il n'en reste pas moins que j'ai effectivement quantifié des gains chrono réels. Il sont à mon avis imputables à : la motivation de rouler sur le vélo de mes rêves, plus de confort, une position IDEALE, et certainement un petit peu des arguments exposés.
VERSATILITY & ADJUSTABILITY:
Over a decade ago, Softride was one of the first manufacturers to embrace the steep angled forward aero position and help push speed to a new level for many athletes. In 2002, we are proud to be one of the first manufacturers to build TT specific frames that directly embrace the fact that Time Trial and multisport athletes have many different body styles and will not all be riding in the same position.
For 2002, Softride offers two new Time Trial/Multisport frames, the Classic TT7 and the Rocket TT7. Both models are built around having the versatility to work well at a variety of common multisport seat angles, including the more relaxed ëslamí position many athletes and fitters are gravitating towards. Top tube lengths are listed for 72°, 74° and 76° seat angles. These models compliment the existing steep angle based 650c Classic TT and Rocket TT models and use the common and readily available 700c wheel size. In addition to these two new models, the new Qualifier built bike works great regardless of what position you will be using (road, aero or other) and brings Softride technology to both the road and TT/Multisport athlete at an exceptional price.
VEHICLE AERODYNAMICS
The rider accounts for over 2/3rds of the drag the entire vehicle must overcome. This makes the rider's positioning crucial to overall aerodynamics and this is where Softride really separates itself from other aerodynamic frame options. Softride technology isolates the rider from road shock, even over rough roads or large surface variations like railroad tracks. This allows the rider to stay tucked into an efficient aero position longer and in greater comfort.
Softride is the most aerodynamic bike on the market for a few very simple reasons. Our bike lacks two major airflow disturbers that virtually all other designs have at least one of ‚ a seat tube and/or stays that extend all the way to the seat juncture. Not having material in high airflow areas drastically lowers the likelihood of turbulence and lowers the drag coefficient. By eliminating the need for long stays or a seat tube, Softride reduces the surface area, from both the front and the sides. This maximizes the frame's aerodynamics without compromising other key variables in the process.
To prove, once again, that Softride is the most aerodynamic bike on the market we headed to the University of Washington Kirsten wind tunnel testing facilities. Comparative drag tests conducted by the University of Washington Aeronautical Laboratory (UWAL) tested what are considered to be the fastest aero bikes in the industry. The tested bikes included a Cervelo P3, Litespeed Blade, Trek Team Time Trial, and Softride FASTT7. All bikes were tested with the same rider, frame size, bike components, rider cadence, and a constant speed of 30 mph. Where did Softride end up? On top, of course! We came in 82 seconds faster than our nearest competitor, the Cervelo P3. Talk about maximized aerodynamics!
COMFORT & FATIGUE:
After 14 years of winning races, all our athletes have the same comments; I am more relaxed, and more powerful.
Races are won by seconds, why would you give away minutes due to fatigue caused by harsh road vibration. Vibration prevents the muscles from performing to their full potential, reducing power output. The rider should put 100% of their energy toward propelling the bicycle forward, not trying to accommodate for every bump in the road. Recent test results show lower average heart rates while at the same time producing more power output than a conventional bike. (See test 1A) This improvement in heart rate and wattage was seen on a suspended Softride bike.
CORNERING:
The proportion of sprung to unsprung weight a vehicle has directly effects cornering performance and traction. What is sprung and unsprung weight and how does it effect cornering on a bicycle?
Unsprung weight is the portion of the bicycle and rider that is not suspended (fig A1). The more unsprung weight that is forced to respond to the road, the slower that weight is able to react, resulting in less consistent tire contact with the road. On a rigid bicycle, the vast majority of the weight is unsprung. Sprung weight on the other hand, is the portion of the bicycle and rider that is suspended and does not need to adapt to the road beneath it in order to maintain traction (fig A2).
Suspension changes most of what is unsprung weight on a rigid bike into sprung weight, drastically reducing the weight that has to adapt to the road. Suspension takes the load off the wheels and tires, allowing them to react faster and more accurately to the road below them. This reduces tire deflection, keeping tires in more consistent contact with the surface below them and is why suspension enhances traction and allows the rider to corner faster and with greater confidence (fig B1).
ROLLING RESISTANCE:
Pavement is riddled with surface imperfections that slow a bicycle down. Without suspension, both the rider's and the bicycle's weight must be lifted up and over these imperfections for the vehicle to move forward. With suspension, the majority of the weight is sprung mass. Only the unsuspended portion (wheel and lower frame) and a small amount of the rider's weight need to be lifted (about 35 pounds for both). It takes far less energy to lift 35 pounds than 175.
Suspension also directly reduces tire rolling resistance. Tire rolling resistance is not as much about tire width or tire pressure as it is about consistency of tire contact patch. The more consistent the tire's contact patch is with the road, the less rolling resistance the vehicle will have.
How can Softride bikes affect these variables? Without suspension, the majority of the vehicle's weight is unsprung and the road imperfections must be absorbed by the rider and tires. Therefore, the vehicle will be slowed as the tire deflects and deforms in an attempt to absorb the shock. By redirecting the load into the suspension system, the tires are kept from having to deflect as much. The more consistent the contact patch, the lower the rolling resistance and the less energy the rider will have to use to overcome the resistance.
TORSIONAL STIFFNESS:
Road vibrations detectable by the human body usually fall between 500 - 700 Hz depending on the speed the bike is traveling. The different materials that are currently used in bicycle frames only damp vibration above 2300 Hz. Materials like carbon fiber do not actually offer any significant advantage in shock absorption when used in bicycle frames. The frame design, not the material, is what really determines how a frame rides and feels. This makes it possible to have a super stiff titanium frame or a whippy aluminum frame.
Individual materials have gained reputations for certain ride characteristics because of the designs they often lend themselves to, not because of the material itself. Frame materials on their own cannot absorb vibrations below 2300 Hz. without sacrificing torsional stiffness. This is where suspension comes in. Beam suspension allows a Softride frame to effectively absorb road shock and vibration and not sacrifice exceptional stiffness.
c est qd meme cher) se ruiner :