much depends on the axle capacity. I've found springs on 5200/6000/7000/8000
/10k leaf spring trailer axles have very little compression/rebound while going down the road.
However hit one of those RR track on secondary state highways that can bottom out the suspension. I've had no problems with 2 1/2" at the top.
Lots of trailer owners may see tire marks at the top of the wheel well. Most of the time that comes from the suspension walking through a ditch.
Most of my other non rv trailers do it but it doesn't hurt anything. Its just a short kiss at 2 mph.