To be safe I use three ramps and walk the bike up under power. I have used one and clutched it up while standing next to it, just gotta have some faith in balancing it while you climb up on the tailgate. Have done it without power with the help of another person, get a bit of a running start, push it up the ramp as far as I can reach, have the other person spot on the right side and give it the final shove after I've climbed up in the truck. 200lb dirt bike is no problem to push up the ramp myself, 400lb sportbike I need help with that last shove. I used to hit the ramp at speed and ride it up, then my ramp slipped off one day. Your Ranger should be a bit easier angle than my truck, as others have said if you can use some terrain to raise the front of the truck or lower the rear it helps a bunch. Tie the ramps to the truck to help prevent them slipping off also.