However, while our autotourists are looking through their fingers and they don’t find fault with the TSU sticking out from under the bumpers. However, in the event of an accident - an unreleased coupling is not interpreted in favor of its owner. That’s why towing devices with removable balls are becoming more and more popular. In addition to safety, they also have another advantage - during intensive use, the ball wears out (the minimum permissible diameter is 49.5 mm), and replacing it is much simpler and cheaper than the entire hitch.
There are two variants of execution: an easily removable ball, bolted to the TSU frame, and automatic - the removable head is latched. The first, as a rule, is cheaper and with occasional use, perhaps, more appropriate. The second, of course, is more convenient, but more complicated, more expensive, and you can lose the keys to the lock.
Note that the size of the ball and the free space around it are regulated by GOST 28248–89, similar to European standards, but the balloons of the American standard vehicle are thicker. Their normal diameter is 2 or 178 inches, i.e. 50.8 or 47.62 mm. You can even lock the trailer lock on a two-inch one if you wish - you only need a sledgehammer. Only cases are known when such a coupling was disconnected at the most inopportune moment. The same thing happens if an American castle is put on a European ball. Therefore, when buying, for example, a used "American", you need to take care that the ball matches the trailer lock.
Tests of the TSU according to OST 37.001.299–93 and the European Directive 94/20 do not fundamentally differ, therefore the couplers of European manufacturers are certified for Russia. Permissible load is indicated on the nameplate. On ours - the maximum vertical load on the ball S (kgf) and the permissible total mass of the trailer. In Europe - the maximum horizontal force D, determined by the formula:
D = g Ma Mп (kilonewtons), Ma + Mп where g = 9.8 m / s2, Ma - gross vehicle weight, MP - trailer.
Imported products (the most common are Brink, Holland, and Bozal, Hungary) are made perfectly: without sharp edges, flashing, neat welding seams, and strong color. Ours is simpler. Nevertheless, both of them successfully passed the tests - 2 million loading cycles with the installed force with a frequency of up to 35 Hz. Only ours, however, are much cheaper and equipped with wiring. Imported - not always. A branded harness with adapters (unloading relays for a computer system) can cost up to $ 200, and a regular kit can cost about $ 30.