Principle of operation of the brakes.
Good brakes on a bicycle are essential for the safety. The faster a cyclist can stop the better.
How quickly a cyclist can inhibit not only depends on the quality of the brakes.
The maximum delay that can extract a bicyclist, is limited by two factors.
Firstly, it may begin to slip a wheel, and second, the cyclist can go over the head
If a wheel begins to slip depends on the pressure of the wheel on the road surface and the coefficient of friction between the wheel and the road surface.
The greater the pressure on the wheel, the harder it can be braked with that wheel. Because of the braking forces, the pressure change on the wheels.
The pressure on the front wheel increases while the pressure also decreases on the rear wheel.
The rear wheel will therefore slip much earlier than the front wheel.
With the front wheel can then also be braked much harder than the rear wheel. As a guide, can be taken that about 80% of the braking happens with the front wheel.
When only a rear brake is mounted, the braking delay is 40% of the maximum braking deceleration when using two wheels.
Using only a rear brake is not really safe.
The only advantage is that a bike with only a rear brake can never flip over as a result of very heavy braking.
In the rain reduces the coefficient of friction between the road surface and the tire. The wheel will therefore slip in the rain much quicker.
The maximum deceleration is therefore low in the rain. Even if brakes are perfect, can be braked not as hard in rain than in dry weather.
Figure 2 shows the point of the skid situation. Through the braking forces the cyclist has to fly over its handlebars.
How quickly this happens depends on the gravity and deceleration. If the center of gravity is higher and closer to the front wheel, the cyclist will be faster to fly over.
Cycling with a short wheelbase, steep and high seating will during sudden heavy braking quickly fly over.
At the moment that the rear wheel comes off the ground, the front brake is to be released. With a good brake it should be possible to achieve the maximum braking deceleration, both in the rain as well as with dry weather.
A good rear brake must be able to block the rear wheel. With a good front brake is (unfortunately) possible to fly over the handlebars or block the front wheel.
Blocking the wheels or flying over the handlebars should not happen unexpected or easily.
The cyclist must be able to brake in short bursts to avoid this kind of situation.