Just got back from my first trip towing with my new 2015. I installed a set of AirLift 5000 Ultimate air bags.
They worked great for leveling the truck back out after putting the 5th wheel weight on it.
I would not tow it without the bags. It sags too much.

Anyway, the bags worked great. The stock FX4 "Rancho" wanna be shocks.... not so much.

I guess the air bags give the rear suspension extra rebound when going over large dips at highway speeds.

Things got scary bouncy a few times.

I'd hit a dip, like going over a bridge or overpass, where the surface changes level...
the rear end would compress, the air bags would (usually) keep it from bottoming out...
but then they would bounce back up... and then down, and back up....etc etc....

That much weight, at highway speeds, bouncing up and down several inches, several times, before it settled back down... was not fun.

I guess the stock shocks just can't control that much weight and the rebound effect of the air bags.

I like the way the truck rides when not towing. I deflate the air bags and with a couple hundred pounds of stuff in the bed
(auto slide hitch, bed cover, firewood, etc) it rides good. Better than empty.

What would you guys recommend?

I dont want it to be TOO STIFF when unloaded, but NEED the shocks to stop the excessive bounce and suspension travel when loaded heavy.

I'm leaning Rancho RS9000 since I can adjust them depending on needs - empty vs. loaded.

Any input is appreciated.

Obligatory pic lol

 

I use Stable Load wedges on ours without airbags. The truck does not seem stiff when the wedges are engaged while we're towing the 5th wheel. We do not experience much, if any, exaggerated bouncing motion. The truck just feels confident and follows the contour of the road. Better shocks may also help with your problem.

 

Great looking setup! New shocks will definitely help, but did you try to use some different air pressures as well? It almost sounds like you may not be running enough air pressure in the bags.

 

I was at about 70-75 psi (both sides) to level things out.

 

I can't see how shocks would make any difference in the world. You metion first tow, have you towed heavier loads before? Heavy loads create a more dynamic force, watch some big rigs go over the same pavement annomilies. Things are gonna move around. My 08 has the factory rear shocks at 65,xxx miles, I do not have air bags. I tow about 14,000 pounds (no sag) and I just can't imagine a shock controlling much of anything on the rebound side at that weight.

Why do these newer trucks need air bags anyway? I'd be looking at the soft springs if anything, maybe buy some from an 08!

 

Not my first tow ever, just my first time towing my 5th wheel with this truck. I've towed this trailer with my 2004 F250 since May 2013. Nearly 10k miles worth.

My 04 had the camper package with overload springs, AND Timbren bags, AND Rancho RS7000MT shocks. Which are a monotube gas charged shock.

Shocks help by SLOWING the dynamic forces. Good gas charged shocks control both compression and rebound better than a standard shock.

My new 2015 DOES NOT have the camper package with the additional overload spring. It only has two main leafs and one large leaf at the bottom of the pack that serves as an overload spring once the suspension is compressed A LOT. Too much in my opinion.

I added air bags because I didn't like the stance loaded. Too much squat. I never even bothered towing with it squatting like that, I know a nose high rig doesn't tow well.

Once I air up the bags to get back level, the overload is no longer engaged, which puts all the work on the two soft leafs and the bags. The bags have zero rebound control. Think bouncy exercise ball. You can compress it and as pressure goes up, it controls compression. But when it bounces back - it bounces way back! lol

I'm hoping good shocks will slow the bounce back, which will in turn reduce the amount of travel in the bounce before things settle back to normal.

I'm also researching something like the Torklift StableLoad devices that make the overload engage sooner. This will take some load off the bags, hopefully reducing bounce back.

Another option is to swap out my stock 2" F250 rear blocks for some 4" F350 blocks. This way when it's compressed under load to the overload springs, it wont be sitting as low in the rear. And unloaded it'll give me a slight forward rake (higher in the back) which I prefer over level or lower in the back.

Here's pics without air first, then with 60psi ...... The squat looks worse in person than in pics....

 

Try the Stable Load wedges. They did the job for me and improved the ride without throwing things out of level. Blocks can create more problems. I've seen comments saying the wedges work well with air bags. They are easy to install.

 

Cheapest I found the StableLoads for was about $210. Seems high for some generic hardware and 1/4" plate steel.

Yesterday I made some DIY stableload wedges out of treated lumber to see how pre-loading the overload springs feels. Didn't get to take it for a test tow yet. If it feels right, I may make some better wedges. I may even give in and spend the money on some real StableLoads for the easy bolt on convenience. And I do like the idea of putting the factory overload spring to work, rather than bypassing it by relying completely on air bags.

Either way I'm pretty sure I'm going to upgrade shocks regardless.

 

Try taking air out of the bags....

 

What good would that do? It takes a certain amount to get level. Any lower and it's not level.

That's why I was thinking 4" blocks instead of 2".

Right now, stock suspension, no air in the bags, with my heavy auto slide hitch, roll-n-lock bed cover, a little leftover firewood, and about 16' of treated 2x8 blocks

.... truck sits level.

That's not much weight. A few hundred pounds maybe. And the truck is already level. It was near level with nothing at all in it.

Any more weight and it's drooping butt.

 

I got a chance to tow a few miles today with my homemade stable load wedges. Worked pretty good.

With no air in the bags the squat was less than before. Ride was decent, felt stable. Didn't get to hit any highway speed dips though.

Still took adding air to get back to level, just not quiet as much to get there.

Will probably buy the real StableLoads just for the convenience of a bolt on application and the quick/easy disconnect.

Will also get new the Rancho RS9000XL shocks as the budget (wife) allows lol

 

Why do you need it to be level? Try taking 15psi out and see what happens...

 

I've always been told level tows best. I'll try messing with the pressure and see how it does.

 

Level on the trailer tows best. Let the suspension do its job.

 

i dont have much to say other than that is a great looking truck! seems like you're set on rancho 9000s, be sure to come back and update this if you do and let us know how it affected your setup. I'm leaning towards them as well.