Around 2000 BC, several tribes from the steppes near the Black Sea brought horses to the Tigris-Euphrates valley and began to use them to pull wheeled carts, which by this time already had wheels.

It is unlike the earlier wheels, which were made of wood throughout.

In the 1st century B.C., Roman craftsmen modified the Celtic wheeled carriage by using a rotating front axle to form a change in the direction of rotation, a whole rim with a wheel hoop to increase strength, and a wheel hub with a metal rim to reduce friction.

The performance of the carriage was greatly improved.

The carriage is mainly composed of the following parts: yoke, reins, saddle and other chassis parts, axles, wheels and other body parts, and flat plates.

Carriage is a horse-drawn car, or carrying people, or cargo.

The history of carriage is extremely long, it is almost as long as the civilization of mankind.

Until the 19th century, carriages were still a very important means of urban transportation.

People loved the elegance and poetry of the carriage, and enjoyed riding it with ease through country avenues or old city streets to visit friends.

With the advent of trains and automobiles, the wheels turned faster and faster, and the horse-drawn carriage was gradually eliminated.

It is worth mentioning that the four-wheeled carriage was basically invented at the same time as the two-wheeled carriage.

But until the Hoosier War in the 15th century AD, the use of the four-wheeled carriage was far less popular than the two-wheeled carriage due to the imperfect steering system and the high cost of production (except, of course, for the ancient Roman Empire with its 80,000 km).

And by the 17th century, four-wheeled public stagecoaches took on almost all long-distance passenger transport tasks, and the ornate decorations and beautiful horses that went with them became cool status symbols for European royalty.

On the basis of having wheel axles four-wheeled carriage was easy to achieve, only needing to change the suspension of the front wheels to a large disc.

The part of the carriage that articulates with the body can be combined with the front wheel suspension, making the front wheel suspension follow the overall steering when the horse turns.

Due to the role of the rollers in the wheels, the front and rear wheels can automatically adjust the speed difference between each wheel (in fact, even without the rollers, it does not matter, except that it is more expensive wheels and affects the horse's power).

This type of suspension can not do small angle steering, can not do too fast sharp steering, and the front wheel suspension and the entire drive train structural strength requirements are high.

Carriages have two wheels and four wheels, the two universal different.

Their own characteristics are not the same, from the difference between two-wheeled carriages and four-wheeled carriages we can see that the advantages of four-wheeled carriages in their own stability, the advantages of two-wheeled carriages in their own speed.

The same horse, in the different vehicle traction, the force required to consume different.

Two-wheeled carriage can be part of the weight of the body on the horse's back, so the horse will need less force to move forward.

While the four-wheeled carriage weight is heavier, in the forward momentum all need the horse to move forward by the collar on the neck to pull.

This is what we see when the two-wheeled carriage appeared basically a horse, four-wheeled carriage appeared when most of the many horses traction.