The triathlon bike
One could simply say that the geometry of the bike will make running more comfortable. On a triathlon bike, the aggressive angle of the saddle tube, towards the front, will allow you to make the best use of your quadriceps. On a traditional bike, the more “relaxed” angle of the saddle tube takes into account the fact that the riders use their tendons much more: the triathlon bike will do more to relieve the tendons, saving them from running.
First of all, do we ask an important question: what separates a triathlon bike from a road bike?
The essential difference, except for the riser, lies in the angle of the tubes. Triathlon bikes tend to have a larger saddle tube angle (74° or more). In other words, you will find yourself, in Saddle, much more above the bottom bracket, more forward than a road bike. This angle will allow you to be in a comfortable, aerodynamic position. Finding yourself in this position, as in an Ironman, will not only save you time but, more importantly, you will also save a great deal of energy. And it’s much easier to rest on your elbows than on your hands.
Just remember that the least aerodynamic thing on the bike is you. It’s not a few details like wheel profiles or helmet profiles that will change anything. The more you simplify your equipment and the way you get into the air, the faster you will go.
Which riser to choose
The main interest of the extender is to allow to adopt a more aerodynamic position, by favoring the lowering of the bust, and the approximation of the hands and elbows … thus decreasing the CX (coefficient of penetration in the air) but also the frontal surface that enters into consideration in the improvement of the aerodynamics. The riser must also allow the rider to maintain a comfortable position, allowing the running to continue smoothly. There is no need to install an extender on a bike if you cannot use it, or if your position does not become more aerodynamic. The choice of the suitable extender is not always easy but, provided certain basic principles are respected; it is possible to find one of the following three main categories.
There are three main categories of extender
They are primarily intended for mounting on a road bike. If we consider that the optimal position in terms of power and comfort, on such a bike, is obtained with the hands on the cuffs and the forearm supporting the hanger, we can see that the ideal extender must have the following characteristics: :
Its length should not exceed the cuffs, and the armrests should be as close as possible to the hanger. Otherwise, the position will be too long and too straightened, losing the advantages of using the riser!
Also, these short risers allow respecting the regulations in force on the races with drafting (ITU, Grand Prix, French Elite Championships,…).
Due to their short length, their arm rests (when they exist, see Spinacci) are often placed near the wrists or almost below. It is not, therefore, to be expected to be of remarkable comfort. However, this element of comfort is not necessarily crucial because, on a road bike, the weight distribution makes that the main support is the saddle, limiting the weight supported by the arms … on the other hand, the tests with drafting limit the interest of the aero position, so the time spent in this configuration is sometimes quite limited.
Like the short risers, these fix themselves on an independent hanger, hence their name Anglo-Saxon of “Clip-on” … but they are longer than the previous ones, with generally more comfortable armrests, both because the pads are more provided than because they are placed more under the forearm than under the wrist.
Intended for more specific triathlon settings, with a more advanced position than the classic one, they are nevertheless quite versatile, and it is possible to find the right model, whatever the position.
The horizontal position of the armrests:
it is simply the distance between the saddle and the armrests … given the more advanced mass distribution than on a road bike, the weight supported by the arms and the extender will be more important. Hence the interest to place the armrests as close as possible to the elbow, thus allowing skeletal support, rather than muscular, and to reduce the overhang, important on short risers (see illustration below).
The height of the handlebar is secondary; it is the riser that pays the price … the use of various brackets, spacers, etc. will allow having a certain range of adjustment. Nevertheless, be careful when you choose, because in some cases, the combination of an upper head tube and a riser with high armrests prevents you from lowering the bust sufficiently, ensuring a good aerodynamic position.
The length of the hanger: no mystery for this setting … measure your forearms between the place where you want to position your armrest and the place where your hands will grab it … for the adjustable length risers, no worries. These risers, of course, attach themselves to all kinds of hangers, classic road.