If you have 'dragged' once, you will 'drag' many times over the years. My last unit that I had, I drug one of that bars completely off. I added drag wheels and they were on the cheap side with junk rubber wheels and they pulled off on the second 'drag'. Added steel drag wheels and the worked very well. Still be very aware when you go out of a sloped drive/ gas station and onto a level road way and your unit is 'too long' and will 'lift' in the back as you turn into the road. If you have room to manuviour, when pulling out, take the 'transision' at a slant and not 'head on'. Also, a few campground 'sites' are not level enough and you will also drap, backing in and pulling out. DO NOT put your drag wheels lower than the drag bars that are on your unit, you want them close to the same height. You will drag more often if lower and then comes the possiability of bending your frame from a hard hit/drags.
2013 Forest River Salem Hemisphere SBT312QBUD
2001 CrewCab F-250 7.3 PowerStroke Diesel
SuperChip, BTS transmission, 6.0 Trans Cooler