F150 porpoising under Travel Lite 625SL

What tires an shocks are you running?

I up graded to 'E' tires @ 80 psi and blistein shocks.

See my profile, I had a Travel-lite 800

When I owned my half ton I installed Hellwig helper springs and c rated tires that did the trick.

Tires and quite possibly too little tongue weight.

la2jax wrote:
Hello,
I have just purchased a 2015 F150 (20K miles) and put on a 2017 Travel Lite 625SL (1,300 lbs).
We are getting surges frequently and every few miles there is some good bouncing. A few times we had to slow considerably to reduce excessive porpoising.
Dave

You don't mention which model F150 you have (GVWR + Max Cargo Weight). Ford data sheets (depending on the model) show a cargo capacity range from 1486# to 2558# (and everything in between). You'll either be well within the cargo capacity or close to overloaded. I'm not a weight cop but you need to find out where you're at on the charts for the full, proper fix.

That said -- is it truly "porpoising" or more of a bucking? Does the front end (rear end) rock up and down back and forth or does it feel like the bed and cab are fighting each other? One is caused by excessive frame flex while the other can be (generally) solved with shocks. Google "camper bucking porpoising" and you'll see endless discussion and possible fixes. Some acceptable - some, not so much!

Assuming you have one of the higher GVRW F150's and your camper CG is within acceptable range, I'd try a new set of Bilstein 4600's on all four corners (or Rancho 9000's). Top notch shocks are the first thing you can do to clean up a crappy ride.

I'll let others chime in here as I'm sure there will be no end to the suggestions and scolding about weight. :@

donn0128 wrote:
Tires and quite possibly too little tongue weight.

Don, it's a truck camper, there is no tongue weight. It's posted in the truck camper section, only weighs 1300lbs, and the OP talks about still being able to close the tail gate. I know its early on a Saturday morning, but did you even read the post?

As suggested, Hellwig helper springs or Super Springs along with LT tires should solve your problem. Changing shocks will help too, but not by themselves.

Most F-150s are sprung for personal comfort and a very smooth ride, but often flex too much when carrying a heavy load. I prefer Super Springs. Very easy to install and dose not stiffen the ride until a load is added.

I have the OEM shocks and tires. Dynapro ATM 275/55R20 113T, E4 weight rating (?), max load 2535 lbs @ 51 psi. I've been running 40 psi, maybe I should increase pressure?

My truck was built for Canada so my door jamb sticker is a little different. I don't remember how I did my earlier calculations but using Ford data I previously came up with a load limit around 2,070 pounds. I was confident that my 1,300 lb camper would work.
Btw, just upped my tire pressure to 50 psi. Notably rougher ride and no apparent improvement on the surging. Heading out on the interstate soon for further testing.

Is it the truck porpoising, or is it the camper porpoising on the truck? I've run a Travel Lite 770SL on a Dodge 1500 4x4, and the truck was always rock solid. I did have Timbrens on it. On different occasion, mostly due to road conditions, the camper would porpoise on the truck. What type of camper mount system do you have, and what is in between the camper floor and the truck bed. PS. My 770SL is supposed to be 1335#'s. With only the electric jack conversion, which shouldn't be more than 50 #'s, it rang up 1700#'s on the scale!

The truck is surging frequently, bouncing at times and porpoising on occasion. We have Torklift mounts and the camper sits on a factory plastic bed liner. I believe the mounting to be rock solid.