On Fri, 29 Jun 2018 03:44:04 GMT, Ron
m wrote:

I'm thinking of making a motorcycle ramp 8 ft long & 3 ft wide with 3/4 inch
plywood to load a 600 lb bike on a car hauler trailer. Will the 3/4 " plywood
hold the weight?

It really depends on how you support it. Make a full length
wedge-shaped piece to go on each edge (make sure they're all _unde_r
the load-bearing surface--you want them to hold it up) and one in the
middle and if you're not on pavement lay another piece of ply under it
so it doesn't sink into the ground and put in some cross-bracing so it
doesn't collapse sideways and it should be fine.