General

The trucks are an extremely important part of a skateboard. Aside from the obvious function of attaching the wheels to the deck, the trucks are what let the skateboard turn. A truck consists of a baseplate that is bolted to the deck, a hanger with an axle to hold the wheels, and a kingpin bolt with a pair of bushings that the hanger pivots on. Even though skateboards have been around for a long time, trucks haven't really improved much in the past 50 years.

Brands

There are a ton of truck companies on the market, but still these old brands, with a long history in Skateboarding are rocking. It is possible that over 80% of all skateboarders skate one of these brands, for a simple reason: they are the best!

Independent
Indys are the best turning, best grinding and strongest trucks that you can get. The new Stage 9 truck is the lightest ever made. With a new super strong kingpin and unbendable axles this truck is untouchable. Also available in a few colours but to be honest with you, if you get the raw ones you can use the money you saved to spray them any colour you want.

Thunder
Thunder trucks are the choice of the connoisseur. They have a slightly wider turning circle than Indys, which makes them a little more stable; this is why manual freaks like Marc Johnson ride them. The high version make a great alternative to Indys if you ride massive boards, like Ed Templeton.

Venture
The lightest, most stable and lowest of the three; Ventures are often the choice of the tech block/flatground champion. A board mounted with ventures is so easy to learn new tricks on; it’s so light and responsive.

Material

Skateboard trucks are made out of aircraft-grade heat treated aluminum alloy and include strong grade hardened steel axles and kingpins. Bushings and pivot are made out of Poly Urethane (PU).

Turning

When you lean to a side of a skateboard, it turns. The deck tilts and causes the trucks to pivot. The wheels on one side of the skateboard move closer together and the wheels on the other side move further apart. If you tilt the deck as far as it will go, and then extend a line through each axle and find where they cross, you have the minimum turning radius of your skateboard. The smaller the turning radius, the sharper turns you can make. For most types of skateboarding, a smaller turning radius is better (but too small can be dangerous). Many things determine this turning radius: truck geometry, wheel base, deck height, wheel size and shape, and so on.

Bushings

First, even with the best geometry, a truck with crappy bushings won't turn very smoothly (that's not to say that good bushings will fix a bad truck either). Bushings are made of urethane. High quality urethane has a high rebound, which makes your trucks recover quickly after a turn or after landing a trick. But high quality urethane isn't cheap, so some truck companies try to save a few bucks by using low quality urethane to make bushings. These bushings are stiff and don't have much rebound. The result is a truck that feels slow and unresponsive.

Truck Geometry

Truck geometry refers to the action angle of the truck. If you draw a line from the tip of the pivot stem through the center of the ring, the action angle is the angle between that line and the horizontal. The hanger pivots on this line. It's the most important thing that determines turning radius. The larger the action angle, the more the hanger pivots for a given amount of deck tilt and the smaller the turning radius is. Changing the kingpin angle or the pivot stem angle can change this action angle.
So if you need more clearance between your big wheels and your deck, buy some riser pads instead of HI trucks. You'll save some money and your skateboard will turn better and it'll also be more stable.

width of hanger (without axle)
5.0"
5.25"
6"