I have a 06 open car trailer with a metal sides and wood center. I added the wood center( un treated 2x6) about 8 years ago. This year i stripped all the rust and paint off the metal decking to repaint. The wood deck i just put back on. I still park my 3klb excavator on it just fine.
I also have a 2wd tractor with double ring chains. Its nearly impossible to get the thing on there with the metal deck. Even my rubber tire excavator slips on a wet diamond plate deck some. My trailer just has a 2ft bever tail so no where near as steep as a tilt trailer.