Top semi trailer manufacturers in the previous article more than once mentioned the middle axis of this model, but there are always card friends in the following disdainful reply: this is the whole trailer ah, did not alter a name? Then we can get on the highway? Actually, the middle axle trailer and the full trailer look extremely similar in appearance, and numerous people think that they are the same kind of car. But in fact, the middle axle trailer and the full trailer are somewhat different. Axle positions are different. middle axle trailer, as the name suggests, is to put the axle in the middle, because the middle axle trailer because the axle is located in the middle of the trailer, so it can not maintain balance alone, independent parking must rely on additional support rods. The full trailer has two axles located on both sides of the vehicle, independent parking can maintain balance. Thus we distinguish between a mid-axle trailer and a full trailer mainly by looking at the position of the axle. Traction hook positions are different. Full trailers and mid-axle trailers are not connected to the main vehicle in the same position. The full trailer is connected to the main car through the traction hook installed on the main car frame, while the traction hook connected to the main car is located under the frame and indirectly connected to the main car frame. Because the axle of the middle axle trailer is located in the middle, the main vehicle pulling the middle axle trailer should bear part of the weight of the trailer, but this proportion is typically not too large, and the main weight is still on the middle axle. The full trailer only bears the horizontal action from the trailer, without bearing the vertical weight of the full trailer. Different astern operation The front axle of the full trailer is equipped with a bogie that can rotate along with the direction of the main car. The advantage is that the steering is flexible, which is more suitable for turning and steering of vehicles on narrow sections. But at the same time the disadvantage is very obvious. The reverse is extremely troublesome. The driving skills of the driver are very demanding, more difficult than the semi trailer. The middle axle models that are hot on the market now look extremely similar to the whole one, but in fact they are entirely different. First of all, its axle is concentrated in the middle of the carriage, second, it does not have a bogie, in addition to the traction device can not move up and down. Because of this, a portion of the weight of a mid-axle trailer must be borne by the tractor. Once away from the tractor, the trailer will lose its center of gravity and "collapse" on the road. Overall, the middle axle is more like a semitrailer, so it's easier to backup than it is to completely mount. Possibly the biggest difference between the two is that mid-axle models are legal on the road, while full-trailer vehicles are not allowed on the highway. With this, the middle axle will no doubt become an alternative to the full trailer and become a hot model in the sedan market.