If you're stuck and need a quick ramp to load your bike here's what I use. It's not elegant, in fact it's quite "Agro" but it gets the job done.
It's all wood. Fir is best but it's heavy. If you use Fir you can get away with a 2x10 but a 2x12 gives you a little more leeway. If you use spruce DO NOT USE LESS THAN THE 2 x 12. And as noted find one with very small and few knots. Certainly no loose in the hole knots. Knots are weak.
Scew on the cleat and add the screw eye. In use you either need a buddy to stand on the lower end or the strap as shown to tie it down so it jams up against your tailgate. DO NOT TRY TO USE THE RAMP WITHOUT THE STRAP. I tried it with the bike running so I didn't need to push it up the ramp and the last little easing of the clutch spit the ramp out and I dern near lost the bike. For coming down the strap is obviously needed to keep the ramp in place. The chamfers on either end aren't really needed but it sure does ease up on the effort needed to jump the bike up over the edge.
That's it. I didn't put on a length as that is dependent on your truck bed height. Mine is 8 feet and it worked super on my old 2WD Nissan. For the new Dakota 4WD it's a trifle short but if you use the engine or a buddy to do the lifting it's fine. Goind down is no problem.
Now, do I need to put in a drawing of the foot stool I use for stepping up onto the deck?