Have not actually had my dogs on it yet but I think it will work for them.  It slides very easily for adjusting the length, is wider than most ramps which was a must and isn't overly heavy. It doesn't seem to sag when I put pressure on it so I'm hoping it will feel sturdy when they walk on it.  The only negative thing about it was that it doesn't have anything to hook the top of the 
 ramp to the car or bumper - just 2 small rubber feet on the bottomside.  Strangely enough when
 I set it up and applied pressure downward it only slipped a couple of inches, but not sure that it might not slip more when a 140 lb. dog went down it.  It would only take it slipping once to make them not want to use it.  I still think it's the best ramp for the money and I have figured out a way to drill a couple of holes in the top and slide a couple of bolts through it and behind the bumper to keep it from sliding.