I've been browsing threads on this subject, but I can't find what I'm looking for. I would like to build a ramp for my trailer and am trying to figure out the minimum length so that the mower will clear on what is called the "ramp over angle". The only thing I have found so far is a formula that states the length of the ramp should be 4 times the height of the trailer bed. Does that sound right? Any suggestions on how to figure the length would be appreciated. Thanks.