Analysis of the phenomena that come into the play of adherence between the tire and the asphalt

The function of a tire is to allow the transmission of motive power to the ground from the engine, as well as to provide some grip when braking and cornering and provide some comfort to the pilot and passenger.

The power transmission occurs due to friction between the tire and the ground-up rubber of the coupling between grain and soil.

The full force of friction on the road is the relationship between the coefficient of friction and the load acting on the wheel.

The temperature of the rubber is important because if a tire is warm, the mixes are better and it softens the texture of the soil coupled with it, giving more grip.
It's good that the body is deformed as little as possible to avoid damaging the wheel of abnormal behavior, which for example can "copy" too the roughness of terrain, which could compromise the structure of the bike.

If the road is wet, the water forms a film between asphalt and rubber, which reduces the adhesion between the two: the draining effect in this case is very important, since the grooves in the tire discharging water from the point of contact between wheel and road.
Conversely tires smooth or slick, are better with a perfect asphalt thanks to the great grip they offer.

The off-road tires instead cleats have spoken and very low operating pressures in order to penetrate into the soil, which in these cases is a low coefficient of friction, and have more grip, thanks to the carcass more deformable, which allows to "copy" the bottom and hold onto as much as possible, ensuring maximum traction possible.

The rolling resistance of a tire is the relationship between the applied load on the tire itself and a magnitude which depends on: the inflation pressure, size of the wheel structure of the carcass, load, temperature of rubber and asphalt and speed. Needless to say that a tire deflates and loads, and very deformed, it offers a lot of rolling resistance, dispersing much of the power output from the engine.

There are two types of tire: tubeless and tube.
The tubeless tires offer many benefits:

     * Lightweight (no tube)
     * Lower production of heat (no friction between tube and tire)
     * Increased disposal of heat (less layers of rubber to cross)
     * More security (in case of drilling the air comes out more slowly)


The only disadvantage is the higher cost to made it.

Definition of terms and factors that determine the road holding and stability

There are many factors that influence the road holding, some very important and others less.

''Generally'' road holding of a scooter is the equivalent of the required bends, and stability is the shift of the weight of the vehicle to the top or at the entrance of a curve, and the stability of motion in fold. A high center of gravity and wheels with small diameters reduced stability, while a low center of gravity and large diameter of the wheels increase it.

It is also very important the rigidity of the frame, which varies depending on the material with which it is built, weight and shape, and weight distribution.

Even with the suspension adds to the medium rigidity ... suspensions of large diameter stems overturned perimeter frame (that''wraps''the engine), rear shock and the central motor drive is certainly a combination that guarantees an excellent road holding (especially if you mount tires on the shoulders low and soft compound). Even the driving position affects the stability and the required lateral driving the front by moving the weight makes it the most''glued''to the road.

The scooters usually have a lower stability and road holding of the road bike, since the soft suspension and other features that improve comfort decrease the stiffness of the frame.

These are the main factors influencing the precision driving.

Information and how to use the product used for the repair of pierced tires.

What is it?: It is a product made by sticky plastic content in cans.

What you need for?: It will allow you to return home or reach a tyre repairer without having to leave the motorcycle on the street after a puncture.

How do I use? You unscrew the cap, the rubber valve to be repaired and we will apply the spray nozzle. Obviously before you must shake the same in order to give more pressure. After that you press the cap of the bottle until the tire is not inflated.

With what tires can be used?: It's suitable for all traditional tire inner tube and tubeless.

How do you manage to inflate and repair? :Thanks to the pressure inside the bottle has a compressor and thus inflate the tire. Fix the rubber hand, precisely because the plastic material that creates a sticky inner layer to the rubber tapping those holes.

Where I can buy it? It is found in the shops of motorcycle accessories, on-line supermarket and a department that have auto-moto. The cost is around 5-10 euros per bottle.

What are the defects and when not to use it? The main flaw is that the tire, after its use, should be thrown. For this reason it is advisable not to use it on new tires or recent to be able to repair. It is rather ineffective in the case of tires pierced or completely eaten.

I suggest that after its use it's recommended to moderate the speed and especially to make a shift of only few kilometers, let's say the strictly necessary.

Locate a small hole that generates slow loss of pressure and advice on repair it.

Surely a long standing problem for us bikers (we hope it never happen), is one of the likely situations that we can deal with.

In some cases - typical example, a nail in the rubber - the problem does not arise, but how to locate a small hole that generates slow loss of pressure?

First, the first thing to check is that the loss of pressure do not comefrom the valve: to determine with certainty, the wheel must be dismantled. A "rude but effective" I used to be when I was little boy with the bicycle is to sprinkled with soap and water: if it bubbles, we have already found the problem .... It can also be a loss localized at the level of pitch circle of a rubber, even though almost impossible on a new bike. Note that - usually - a hole that has not involved a canvas is not dangerous, but in any case it must be caught and corrected.

Then techniques for repairing the tire hollow.

In addition to the classic bottle "inflate and repair" - many recommend that you use it as a last resort because they say its not good for the carcass - it is readily commercially available kit for punctures, generally composed by a kind of corkscrew where there is a peak in small hole where you insert a smole suppository; inside there is air that puffed the tire: you do enter into the hole, taking care to follow the angle from the body left that has engaged the hole in the rubber. Finally, the method most used by professionals is called "curing", and it consists on affix a piece of rubber internally heating the piece by a machine called "cured" thereby closing the hole from the inside.