MDA is a man-made (synthetic) recreational drug noted for its stimulant and psychedelic properties that has been used since the 1960s as a clubbing and sex-enhancing substance, with some similarities to LSD and MDMA (ecstasy). Sought after effects. 1  visual hallucinations.
A wheel alignment is done to make sure the vehicle's wheels are running parallel to each other, and that the tires meet the road at a correct angle, to fix or avoid problems such as irregular tire wear, poor handling (pulling to one side) or a crooked steering wheel.
The kingpin is the mechanism on the trailer that locks it to a road tractor. It is typically positioned between 18 to 48 from the trailer nose. A greased metal grid plate surrounds the kingpin. This grid plate allows the fifth wheel to slide underneath the trailer. When the tractor is backed into the nose of a trailer, the fifth wheel pivots and slides underneath the trailer's grid plate. The fifth wheel then locks onto the trailer's king pin. When coupled to the kingpin, the fifth wheel enables the semi trailer to rotate at the point where the fifth wheel and kingpin are joined.