I have a set (two actually) of these ramps from Harbor Freight. I keep one at my cabin and one at home. I use them mainly for loading/unloading a big John Deere 16hp snowblower. They have good traction and are plenty strong.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=55424
You can get a set of the big aluminum angles that you bolt to the end of a 2x8 or 2x10 at Home Depot or Lowes (and other places). I have gone this route before but never cared for it as the woods ramps are too springy to my taste.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=55424
You can get a set of the big aluminum angles that you bolt to the end of a 2x8 or 2x10 at Home Depot or Lowes (and other places). I have gone this route before but never cared for it as the woods ramps are too springy to my taste.