a skateboard truck maintains truck geometry . the truck includes a support pin including a cylindrical end slideably engaging a cylindrical passage in a base plate , and a ball end residing in a socket in a hanger . a support pin bushing under the cylindrical end is compressible and both carries some of a rider &# 39 ; s weight and holds the ball end in the socket providing a second pivot to the truck . the second pivot eliminates horizontal play of the hanger thereby facilitating consistent compression of the kingpin bushings and improved stability of the skateboard . support pin travel allows off - center kingpin bushing compression for steering and improves shock absorption . eliminating horizontal play allows lengthened kingpin bushings and use of the entire height of the kingpin bushings . the combination of kingpin bushing preload , and weight carried by the support pin , tends to equalize the compression of the top and bottom kingpin bushings improving stability .