DaimlerChrysler showed what it said was the first trailer axle system where the axle tube and its trailing arm suspension beam are integrated in one compact axle housing. Therefore, it avoids doubling of material and stress concentrations.
This Durable Compact Axle (DCA) appears to be sculpted, having a seamless flow of steel from the axle beam into the suspension beam. It is, in fact, a tube to which pressed steel suspension arm halves are welded and then ground smooth. Spindles are friction-welded to the tube ends. The air springs are mounted on cast “tailends” bolted to the axle housing at the rear. Different versions of the tailends allow for different ride heights.
The hanger brackets also are available in three different height variants, requiring only one shock absorber and air bellow type for all ride heights. These allow ride heights from 200 mm to 520 mm (8" to 20"). The normal air bellows is 300 mm (12") in diameter. An option is a 360 mm (14") or 360 mm long-stroke bellows.
The compact wheel bearing set is pressed into the hub and is maintenance-free for the first million kilometers (620,000 miles). This wheel-end is replaceable as a complete set and is the same as on the Mercedes-Benz tractor.
The new DCA trailer axle is available for 22.5", 19.5", and 17.5" wheels. The 22.5" version with 430 mm (17") diameter Knorr air disc brakes has a weight upwards of 421 kg (928 lb). DaimlerChrysler Powersystems — Axles, Mercedesplatz 1, D-34127 Kassel, Germany.