Turnbuckle and tie-down failures are an ongoing issue for a limited number of campers since before we purchased our camper in 2012 with multiple forum threads and almost as many solutions as camper owners. Turnbuckle failures resulting in the over-the-cab impacting the cab were reported back then which is as unique as the recent camper falling to the ground.
The aluminum turnbuckles were rated for 300-350 pounds each and a set of four exceed the DOT regulations for the various FWC camper weights the last time I checked.
Turnbuckle loosening can be caused by either camper movement (typically rotational) or vibration unscrewing the turnbuckle. Careful measurements should be made to detect camper movement which bed-to-camper blocking or increased camper-to-bed friction (by a bed mat) can control.
Turnbuckle and tie-down failure is less common and can have very unique causes. Driving into a dip at high speed can load and unload the truck springs creating enough vertical force to cause turnbuckle failure (i.e. a ballistic camper) and was reported years ago.
The camper wood box is very rigid and some truck makes advertise having a "flex" frame. Driving over rough terrain can flex the frame enough where the load on the turnbuckles is not the weight of the camper but instead the weight of the truck because the camper box is so rigid.
Obviously, driving so the truck suspension can absorb the terrain will greatly reduce turnbuckle and tie-down failures or switching to spring based tie-downs.
Tie-down problems are the dirty "secret" for all makes and models of truck campers. Reading several forums revels problems with every truck camper tie-down system.
I block my camper at the wheel wells tightly, go to fiendish extremes to create firm camper contact with the front of the truck bed, and have four safety chains (each rated to 800 pounds, 3/16" chain) plus the original hook-hook turnbuckles. The blocking reduces the lateral load on my turnbuckles while an event related aluminum turnbuckle failure will absorb energy and the chains will keep the camper on the truck. I also carry spare turnbuckles.
Edited by iowahiker, 26 January 2019 - 04:35 PM.
2013 Ford F-150 Reg Cab, Long Bed, 5.0 V-8, 4x4, payload package + 2012 FWC Granby
Over 900 camper nights in six seasons.
"The frog does not drink up the pond in which he lives" (Proverb)