I tried one on a flimsy entry level 5er 15 yrs ago and the flexing did a lot of damage to the siding and paneling in the bedroom area but the frame didn't break. It was just too long of a lever on the pin. I have some new thoughts... that 5er had an extended box and I have a LB which doesn't need the extended pin box. I bet it would have been better if I used the adaptor on a short pin box. Since then, the shop foreman at a RV dealer shop told me the ext. pin boxes make the frame flex twice as much as the short pin boxes. I've switched the ext. boxes to the short boxes on my 5ers, since then, and he was right. I watch the frame flex in the mirror and it's about 1/2 with the short pin boxes. Craig