ESSENTIAL DESCRIPTION OF THE MECHANICAL VEHICLE AND OF THE ACCESSORIES
The components of a racing bicycle are: the stem, the handlebar curve, the gear lever, the brake lever, the shift cable, the head tube, the front brake, the tire, the rim, the spokes, the hub, the fork, the down tube, the pedal, the toe-grip, the crank, the crankset, the derailleur, the chain, the rear gearshift, the free wheel, the rear vertical sheath, the rear horizontal sheath, the rear brake, the saddle, the seat tube, the horizontal tube, the brake cable and the quick release lever. The most important elements, instead, are represented by the frame, the circles, the spokes and the hubs. In fact, after the chassis, the wheels are the most important part of the bicycle. Currently these elements are manufactured using carbon, which ensures rigidity, strength and lightness at the same time.
The frame consists of: upper tube, down tube, seat tube, head tube, pendants, horizontal rear, dropouts, fork, bottom bracket and saddle knot. To take measurements of the frame to be adapted to the cyclist, it is necessary to know the length of the horse, that of the femoral tract, that of the foot, torso, arm and shoulders. Hand size, weight and overall height are also essential.
The wheels are of various types, to adapt to any type of competition. They can have a very variable number of rays, from 16 to 36 (the latter is the most classic configuration but now practically abandoned at the highest level). The profile of the circle also varies, which can be low, medium or high. In chronometers it is easy to see the use of lenticular wheels.
When buying a bicycle it is necessary to bear in mind the following parameters: low weight, sturdiness, rigidity, elasticity, quality of welds, quality of finishing and choice of materials with which it is made.
The automatic locking systems have been designed to match the need to perfectly lock the foot on the pedal to that of being able to release it instantly with simplicity in case of need. Specific shoes must be worn with a sole with recessed grip to allow walking. These soles have a recess in which a block forming part of the pedal body will be housed. With the simple pressure of the foot on the pedal the hooking occurs, while with a twist movement it is possible to free the foot.
Lenticular wheels
In the exasperated search for the reduced resistance to advancement offered by the air, the design of the lenticular wheels has been reached. They consist of a circle connected to the pinion not by spokes but by two lens-shaped parts constructed with composite materials having characteristics of high resistance and lightness.
Production and marketing of frames
Each company that produces and markets a bicycle, defines for each model some measures that are indicated either with an abbreviation, or with a numerical value, or with abbreviation and numerical value together.
The numeric value usually represents the size of the center-center or center-end vertical. In some cases this value can refer to the virtual vertical, or to the length of the horizontal tube.
However, it must be emphasized that the same frames offered by different companies never, or almost never, have the same actual size, much less the same geometry.
Cyclist technology
Today, thanks to targeted training and personalized athletic preparations, every cyclist can achieve maximum performance with considerably lower efforts than in the past. All this is also made possible by the help of modern technology, which provides us with tools that detect the main physiological parameters, such as the heart rate monitor that constantly and with maximum accuracy detects heart rate during training. Thanks to these instruments and other accessories, the cyclist can set up an extremely scientific training, based on absolutely personal physiological data.
The heart rate monitors designed specifically for cyclists, are equipped with numerous functions, among which, the most important, are represented by the speed sensor and pedaling cadence sensor.
CHASSIS AND HEALTH: SOME PREVENTIVE PRACTICAL RULES
The excessive retraction of the cleats causes a reduction in the flexibility of the ankle, with the result of weighing down the pedaling and straining the thigh extensor muscles + the paravertebral ones.
The anteroposterior position of the saddle affects the position of the pelvis and vertebral column with respect to the pedals; its correct adjustment is essential to optimize the load distribution on the axles of the wheels and to harmonize the action of all the kinetic chains engaged in expressing power on the pedals. Precisely for this reason, an adjustment error can cause excessive overloads on the column.
If the saddle is too high, every time the leg reaches its maximum distension, an excessive oscillation of the pelvis is created, with the result of negatively stressing the lumbar musculature, the nerve roots and the sacroiliac joints.
When the frame measurements force the cyclist to a shorter position than normal, a lower weight distribution on the arms is determined, therefore a greater incidence on the lower back, thus forced, to absorb a greater quantity of stresses coming from the vehicle . On the other hand, an over-extended position subjects the cervical spine to excessive load.
The excessive height difference between the saddle and the handlebar determines a greater stress of the lumbar curve; however, there are no precise rules for determining the height difference between the saddle and the handlebar a priori.
An excessively limited height difference forces the cyclist to an overly upright position, which can be harmful because it determines greater compression at the lumbar-sacral level, especially along stretches of bumpy road.
The excessive length of the cranks, forces the foot to describe a greater trajectory of movement, amplifying the angular excursion of all the joints, including those of the pelvis and the column.
MAIN MATERIALS USED FOR THE CREATION OF A BICYCLE
The weight and cost of the bicycle are two properties that vary inversely. To reduce weight, special materials are used (aeronautical-derived aluminum alloys, and titanium and carbon fiber tops), which are more expensive and difficult to machine.
Steel
The steel offers enviable qualities: low costs, ease of welding realization, ease of processing, high mechanical properties. It also features technological features of varying elasticity and resistance, thus offering the public looms with prices for all budgets.
Aluminum
A large number of bicycles are now manufactured from aluminum alloy.
The main characteristic of aluminum is represented by the interesting value for money.
Aluminum frames are generally technically easier to manufacture.
One of the advantages of aluminum is that it does not rust. However, the use of road abrasives in winter, such as salt, can potentially have a negative effect (this is especially true for unpainted frames).
An aluminum frame is generally "stiffer" than a steel frame; its superior rigidity is mainly due to the larger diameter of the frame tubes. The rigidity of an aluminum frame also determines a lower number of flexions on the frame itself, therefore less energy loss, often resulting in a better pedaling performance.
However, aluminum is a material that generally degrades more rapidly than steel. This partly explains why some manufacturers limit the warranty on their aluminum frames to 5 years.
Titanium
The only real defect attributable to this material is the high cost that brings the price of a bicycle to around several thousand euros, for the rest there are no contraindications; in fact titanium bicycles are unsurpassed with regard to the characteristics of resistance to bending, compression and corrosion. This material has the best weight / strength ratio among all the materials found on the market.
Its high capacity to absorb shocks due to the roughness of the ground, makes it a frame suitable for those looking for a high level of driving comfort, but does not want to sacrifice sporting performance to comfort.
Carbon
Carbon fiber is superior to other materials, especially due to its rigidity.
It has a significantly reduced weight compared to steel and allows to have the "custom-cut bicycle" made, with reinforcements in the desired points. These characteristics make carbon an extremely interesting material that is now widely used on the market.
It is a "model" of braiding of carbon fiber threads, integrated with an epoxy resin compound, a bit like fiberglass.
The manufacturer can choose, during the manufacture of a frame (or forks) which orientation to give to the fibers, and thus modify the properties of the final product.
For example, a tube can have "rigidity" qualities when it is stressed in one direction, and "elasticity" when another effort comes from another direction; there are many possible combinations, depending on the objective sought.
The carbon fiber manufacturing method is relatively complex, which affects costs.
On the other hand, after a serious collision, if the frame "is damaged" it can no longer be adjusted.
Edited by: Lorenzo Boscariol
