cribbing for under TC jacks

SoCalDesertRider wrote:
I refrained from saying anything about it earlier. Since no one else has brought it up, here it is.

The truck's receiver hitch was not made for a few thousand pounds of upward force to be applied to it. I don't know how high you're lifting the rear of the truck by the receiver hitch, but if you're applying more force than the hitch's rated tongue weight, which for most hitches is between 500-1000 lbs depending on the model of hitch, you're likely damaging the hitch.

The damage doesn't come all at once at first. It starts by flexing the hitch over and over, causing tiny stress fractures, typically in the embrittled area of the base metal, called the heat affected zone, next to the welds (being a professional welder, it is part of my trade to know about this subject).

At some point, those tiny cracks get bigger and then run, which leads to failure of the hitch. The final failure is likely to occur when towing something heavy on a bad road, since the constant over flexing and vibration, due to the cracks already there, accelerates the failure time.

The failure is also likely to occur during a sudden, high stress event, such as during an accident/collision, or spinning out on a wet road and jacknifing the truck/trailer. I had a previously over stressed hitch fail during a spinout/jacknife, once. The ball mount cracked and broke in half. The trailer was empty at the time the hitch broke, but had been previously loaded beyond what the hitch was rated for.

I read one comment here talking about lifting the truck/camper 6" by jacking under the receiver hitch. In my opinion, the amount of weight/force needed to lift it that high is excessive and likely far beyond what the hitch is built to take.

Lifting an inch or 2 by the hitch, I wouldn't worry about it. The truck's springs are still holding up most of the weight, depending how much the truck normally sags under the weight of the camper.

Not many trucks sag 6 inches or more with a camper though, unless they're quite overloaded. If sagging so much, the factory springs are insufficient for the load. If that's the case, at that lifting height, the springs aren't taking most of the weight anymore, the floor jack and hitch are. Beware.

As far as leaving a truck loaded all the time with a camper, I have plenty of experience with that. It doesn't hurt the truck or the springs. Commercial service trucks, motorhomes, rv trailers, and any truck with weight mounted permanently on it, spend their whole lives loaded to max capacity. Their springs never get a coffee break.

I kept my old 2500 lb truck camper on my F350 most of the time, with the jacks up, for years. Then I loaded the same truck with a 4000 lb utility body and used it as a welding service truck. For 5 years, the truck stayed loaded, 2000 lbs over it's GVWR, all the time, with no extra support but the springs.

Now I have another camper on the same truck, which stays on it all the time. Still no issues with the springs after so many years of them supporting heavy weights. The springs are very heavy duty and designed to support the weight I've had on them.

My next F350, a dually, spent most of it's life with an 11' service body on it, loaded as a mobile diesel mechanic's truck, with a crane. Then, it became my welding truck and for 4 years, it stayed loaded, 2000 lbs over it's GVWR, all the time. I wasn't having any issues with the truck's heavy duty springs at the time the truck burned down in a fire and was put out of service.

My current truck, a class 7 International, spent it's whole 14 year life loaded to it's max GVWR, serving as a brush fire truck with the US Forest Service. The springs are fine. It's getting a break now days. Since it became my welding service truck, it's only loaded to 13,000 lbs under it's GVWR. The truck thinks it's gone to heaven.

There is no need to fear leaving your camper loaded on your truck full time and letting the truck's springs support the weight. They are designed to do that ,provided they are not being grossly overloaded. If the springs are overloaded, they should be upgraded. Your truck camper carrying experience will be greatly improved, with heavier duty springs, rated properly for the load.

Very interesting stuff Socal. My hitch is rated for 1800 pound tongue
weight. It is quite massive. Now that being said you may be spot on. My particular truck is not overloaded. I may just let it sit on those springs after all. All though it seems to me continued heavy load on any spring is going to cause some wear and tear.