We’re going to start basic here to make sure everyone is on the same level.
Baseplate - The part that bolts to your board.
Kingpin - Traditionally this is the main bolt in the center of the truck. The PKP truck has 2 kingpins that are mounted in parallel to each other. They slide into the baseplate from above.
Hanger - The main moving part of the truck. On a PKP this has no solid coupling to the baseplate so may be referred to as a “floating hanger”.
Bushings - On PKP these act as the main interface between the hanger and the rest of the truck. They control every aspect of the ride feel.
Cup washers - Keep the bushings central on the kingpin and stop them slipping around during riding.
Kingpin Nuts - Apply pressure to the bushing and hanger assembly. They can be adjusted to set preload on the bushings.
Axles - Screw into the hanger and allow the wheels to be mounted.
Grub Screws - Are used to secure the Axles in place
Axle Spacer - Keeps the wheel bearings correctly spaced away from the hanger. On some electric setups this will be replaced by drive mounting hardware.
Axle Nuts - The nuts that hold hold the wheel on.
Features and Geometry
Bushing Seat - The part of the hanger that the bushing sits into.
Pivot Axis - Whilst the PKP truck is able to rotate slightly on all 3 axis, the dual sets of bushings constrain this movement to be predominately in one axis. This is called the pivot axis and it goes directly through the center of the bushing seats, front to back, parallel to the board.
Pivot angle - This is the angle between the pivot axis and the ground. As with many other channel trucks we have been using a pivot angle of around 35 degrees.
Axle Offset (sometimes called Rake) - This is the distance between the center line of the axles and the Pivot Axis. Apex Air has a positive axle offset like many other channel trucks (The axle sits below the pivot axis).
On the PKP Truck there are 4 bushings on each truck. When discussing bushings we will use these names for their positions.
Road-side Bushings - face down toward the road.
Board-side Bushings - face up towards the board.
Far-side Bushings - On the kinpin furthest from the rider.
Near-side Bushings - On the kingpin closest to he rider.
Traditionally the road-side bushing is called the “top bushing” despite being on the bottom whilst riding. Similarly the board-side bushing can be called the “bottom bushing”. We found this gets confusing so prefer using road-side and board-side as they are easier to remember.
When discussing setups a single bushing can be specified with both terms eg. “I use a green cone on the far roadside bushing”.