Getting used to your quad skates is more difficult if the skates aren't properly adjusted. Your skates shouldn't underperform and make it difficult for you to practice. Learning how to properly adjust your quad skates to make them go straight is essential to improving your skating.
Hold one skate upside down in your hand, then access the trucks -- the two axles that each hold a pair of wheels. These trucks are responsible for steering. They require proper adjustment for the skates to function best.
Use the wrench to loosen the kingpin of both trucks. The kingpin is the large bolt that penetrates the centre of the truck. It is the point at which the axle pivots while steering the skates. Turn the kingpin counter-clockwise to loosen it enough for the truck to wiggle when you shake the skate. This requires about three full rotations.
Place the skate on the floor with the wheels touching the ground, then rock it left to right to squeeze the bushings. The bushings are polyurethane disks which sandwich the truck along the kingpin, providing a cushion on which the truck can lean from left to right. Press the skate to the left and right to adjust the bushings evenly.
Tighten the trucks with two full rotations, or until the truck no longer wiggles when you shake the skate. Repeat the process with the other skate. Put the skates on your feet and try skating around. They should glide perfectly straight. Some people prefer looser trucks than others, so skate around for a few minutes before readjusting them to fit your preference. Once the adjusted bushings are broken in, feel free to tighten the trucks a bit more. However, over-tightening them can cause the skate to veer off a straight path, so always leave the trucks loose enough for the skates to lean in both directions without the wheels lifting off the ground.
If any of the four wheels leave the ground while turning, you have overtightened the trucks. Overtightened trucks will make it difficult to skate a straight line.