The suspensions of the motorcycles like any other technological construction developed during the years largely.

So starting many years ago from the saddle springs and elastomers into the small front forks now we have products of smart electronic handling suspension of Moto GP.

If the use of a vehicle was theoretically only in absolute straight move without any bumpy road the suspension systems would not be necessary.

In reality however, the needs are many and diverse in motion.

But how does the suspension works in a modern motorcycle?

There is a fundamental separation of two different operation parts. It is the part of the spring and the hydraulic part.

SPRING

The purpose of the spring is to absorb the pressures on a motorcycle when he meets rough terrain when cornering and when braking.

There are three types of springs: linear, two stage and progressive.

Linear springs are the springs whose distance of each coil to the next (pitch) is the same along its length.

The advantage of this type is that if it is intended for a particular use is easier to set up the suspension and has steadily behavior.

Two stages springs are the type who tries to bridge differences between linear and progressive springs. Two different steps in the coil spring length are usually a dense pitch part and a part more open.

Compared to linear it have softer feel on slight bumps keeping the cost low.

The progressive springs have progressive change in pitch coil to the spring length that helps the suspension to react correctly in most cases especially if the bike doesn’t have linkage rear suspension system.

The type of a spring is determined by K number which depends on the pitch, coil number on the diameter and thickness of the coils and the type of material being produced.

HYDRAULIC PART

The spring which offers so many good in riders comfort has a serious problem. If it receives a pressing force tends to keep it up to gradually stop. It means that it works like a ball that hits the ground and frolicking several times until it stops.

This would be disastrous for bike riding and ensure an impressive drop of the rider in the first road bump.

In all these cases the hydraulic system breaks this bad habit of the spring..

The theory of the operation based on the fluid flow deemed uncompressed (particularly oil) through holes of different diameter.

Trying to simplify the operating logic would say that in case where a quantity of lubricant is flowing in a pipe with A diameter if pressed to get a pipe section third of A would require additional transit time and therefore will reduce the flow rate.

So manufactures proceeded in complex systems of the oil passage and able to stop the oscillation of the spring and can easily regulate the rate of passage, according to the needs of the rider and the type of the terrain on which will move the bike.

The damping of the oscillation process is divided into two opposite effects.

One is the compression damping which is the hydraulic reaction when the suspension is compressed and the other is rebound damping which is the hydraulic reaction when the suspension expands upwards.

This very good system showed some weakness especially when the suspension works in very hard conditions such example is a Motocross race.

Increasing temperature of the shock (up to 150 degrees in a motocross bike) create bubbles in the oil messed with the air that was inside reduce the hydraulic damping.

The solution comes putting a separator between the oil and air which in order to not influence the pressure replaced by nitrogen which is inert to temperature fluctuations.

Also high pressure into the body of the suspension was able to achieve a stronger seal of the hydraulic system.

This development works very well and this system gradually went in the front forks using the internal cartridges.

Checking the motorcycle manufacturers model range, we can see that they don’t use expensive solutions of shocks in all cases, but place a system depending on usage and the need in order to keep the bike at low cost.

Thus for example the majority of scooters and motorcycles for single daily use are not equipped with high quality adjustable shocks.

Instead, if the bike is intended for sports or racing use with high performance engine they equipped it with expensive suspension systems for the best control in extreme conditions..