I like the tri fold ramps more than other types for most applications, since they stick together and you can chain them to the truck effectively. Bi fold ramps may not fit under your ATV, which is a perfect place to put ramps. I made my own separate ramps and used them successfully with hooks to hold them to holes drilled into my tailgate. This worked really well, but you may not be inclined to alter your pickup. The weight of the ATV makes the truck springs move a little, and might even move the truck a little (set the P brake for safety). Movement can allow the ramps to loose their hold on the tailgate and dump your ATV sideways. So make sure they are secured. Although my ramp idea with hooks to hold it to the truck worked, a chain is more secure.When buying ramps, check for these things:

1. Traction on the ramp rungs. They should use step tread or something that grips better than merely a round or square tube. Every ATV I load into a taller full size 4x4 has been a little scary to load up a ramp without some kind of grip system on it. When wet or muddy, the loss of traction can be dangerous. Use traction tape or sand mixed into paint on wood ramps.

2. Steep. Don't get a short ramp for a tall truck. My ramps are 6". That was as steep as I dare to load a 4x4 ATV onto a tall 4x4 truck. Never use separate wood ramps on a tall truck. Longer ramps are less steep, but they might not fit where you want them.

3. Safety chains. If the ramps are relatively steep, make sure they are attached to the truck somehow, or they may move and tip your ATV on top of you.

4. Fit. Is it wide enough for your ATV? When you are done with it does it fit under the ATV with the gate shut. Is it too long to shut the tailgage? Make sure you like the way the ramp fits when not in use.

You should get a ramp wide enough for the tires. You can possibly afford to load a quad that is up to two inches wider than the ramps if you are careful and the tires are wide. I would suggest making sure the ramp is at least as wide as the front ATV tires, if not wider. Wide rear tires may be able to work OK ir hanging over a little.

Trailers may not be nearly as tall as a truck. I often load ATVs into a trailer using separate ramps, unsecured, without smooth rungs. These ramps are not suitable for a truck, but due to the low height of the trailer, there has never been a problem.

Aluminum costs more and is lighter. If it breaks it is harder to get fixed. Steel is easier to repair, but it may get rusty.