Jfet, some thoughts:
The folding end on the toy hauler etc is great as I'd spected one to be built on our enclosed vee nosed trailer we had made and so glad I did. Obviously our enclosed trailer's floor is a lot closer to the ground and the inside height of the trailer is only 6'2" so the extra ramp length is only 18" long approx as I remember. However, it sure changes the incline angle a lot and for the better. It's at home and we are in Florida so I can't look at it right now or take pics. Also, mine is designed for 2,000 lbs capacity. It's thinned (angled) on the end that lays on the ground so there's virtually no bump when driving a wheeled item in. The snowmobiles wouldn't care but we don't have them anymore due to our age and my wife's disability. Had over 30 years of fabulous fun snowmobiling in Michigan and up in Ontario Canada and yes, we sure do miss it.
The reason I wanted the hinged extra ramp length is because we used to have a car hauler trailer I designed and had built to carry a full sized car or pickup behind our Allegro MH's. Had a 70" long folding ramp but was just too steep and the front air dam of our Cadillac would drag before the front wheel started climbing the ramp. Sometimes the bottom of the car would also hit at the top of the ramp. That meant either carrying a 3' X 7' piece of plywood and a 2 X 4 X 7' long spacer support for under the plywood to change the abrupt angle at the end or finding a dip to drop the trailer bed to change the angle. The plywood didn't help the bottom dragging.
So, I designed and welded up a self supporting hinged 48" extension for the existing trailer ramp that I first had welded 6 rectangular tubes 1" X 2" X .187 wall (3 on each side under where the vehicle wheels traveled the ramp. I'd calculated it to have a 6,000 min capacity on the ramp when done. My trailer had a 10,000 lb carrying capacity with a 20' long floor length and weighed 2860 lbs total. Surge brakes and 4 - 245/16/75 "E" Michelin tires with 3042 capacity each. Main ramp end had a 2" X 2" X 1/4" wall folding leg support on the back of the gate to properly support across the extension hinged area. Self storing 5/8" dia spring ball hitch pins made them instantly adjustable for about any gate to ground distance. Hitch pins are your friend and you can get lockable one too!
The ramp gate assembly was very heavy and very stiff when finished even with the mesh ramp floor and it wouldn't twist a bit so to raise and lower it, I bolted a boat trailer winch on the drivers side with vinyl cable rather than rope. Worked slick as can be. Bought a 12V electric winch for it because I'm lazy but never put it on because the hAnd winch worked so good. It had a vee shaped steel lockable storage box approx 3' X 6' x 40" deep in size on the front over part on the tongue to carry stuff and served as a stone shield too. Sold it to our daughter and her hubby and it's used for all kinds of things now.
