I have a 274 RLS Keystone Sprinter travel trailer that I recently towed behind a 97 Ford Expedition Eddie Bauer with a 5.4 Triton. I have recently replaced the Expedition with a 03 F350 CC Longbed w/V10 Triton. It pulls well, but I notice that the rear is more bouncy than I experienced with the Expedition. When I drop the trailer on the hitch, it barely touches the top spring in the rear. As a result, it is only riding on the shocks. I am assuming that it is more bouncy because the Expedition was loaded down for its suspension (hence the use of airlifts) while the on F350 since only the shocks are being loaded down and barely at that, that when it hits a minor bump, there is enough inertia up or down from the tongue weight and it is compressing the remaining play in the shock before it encounters spring resistance. If this assumption is true, what would be the best course of action to remedy? Would tougher shocks or air shocks work (i.e, reduce the amount of play)? What about airlifts to take up the amount of play?

 

This is normal, and how the tow vehicle should react when the trailer is hooked up. If it was riding on the over loads I'd be worried.

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As a result, it is only riding on the shocks.

OK. A little Suspension 101. The shocks on a vehicle DO NOT support the load of the vehicle or the trailer. (Unless you get into high end gas charged units, but that's Suspension 102)

The SPRINGS support the weight of the vehicle, the SHOCKS dampen the action of the springs. Shocks only control the RATE at which the energy of the springs acts.

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I am assuming that it is more bouncy because the Expedition was loaded down for its suspension (hence the use of airlifts) while the on F350 since only the shocks are being loaded down and barely at that, that when it hits a minor bump, there is enough inertia up or down from the tongue weight and it is compressing the remaining play in the shock before it encounters spring resistance.

You're on the right track, but reverse the functions of the shocks and the springs. What you have is springs cycling through their range of motion without any damping force applied by the shocks. They are neither slowing the compression of the spring or the rate at which it rebounds, thus the bounce.

Simple answer - you're shocks are not up to the task. They are either worn out, or simply not adequate for the load.

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If this assumption is true, what would be the best course of action to remedy? Would tougher shocks or air shocks work (i.e, reduce the amount of play)? What about airlifts to take up the amount of play?

For all the info on shocks you ever wanted and more, just follow haroutd around. Read all the recent posts he has put up about shocks, there's some really good info to be had in them.

Waxy

 

Just thought that I would throw my 2 cents worth in. I also tow a lot. The Sprinter is a fairly light trailer. probably around 6k or so. Your truck is made to handle a much heavier load. I think that Waxy is dead on with his take on it. If you have the stabilizer arms on it will help but the bottom line is in Waxy's corner.
I am considering the air ride, there are several out there. Good luck with what ever decision you make. Let us know. there are several of us that do tow and are interested in what you find. Thanks.


God Bless our Troops:

 

I also tow a travel trailer. In your initial post you did not say anything a weight distributing hitch for the trailer. Are you using one? If not I think that that will solve your problem. If you are, you can apply more tention to the weight distributing hitch, which will more evenly disperse the weight of the trailer between the front and rear suspension. That in turn will decrease the bouncing in the rear of your truck. You absolutley should not need airbags for an F-350 with the trailer you are towing.

 

I appreciate the responses. My appreciation to Waxy for the education on springs vs. shocks:-) To answer Groodman's question, yes, I do have a weight distribution hitch, which I cinch up nice and tight. The truck only settles about an inch and a half when I drop the trailer down, and as a result barely tocches the overload spring in the back half of the spring (doesn't touch the front half), so I am inclined to think that Waxy is right in that my rear shocks aren't doing a good job of dampening the spring action. Disappointing though if that is the case as it is a brand new truck with only 6K miles on it now, so either it is a case of bad shocks or poorly mated shocks for this kind of use. If the latter, then sad considering this is supposed to be what the truck is designed for. Oh well...guess I will be shopping for a new set of shocks. Now I just need to decide between the Bilsteins or the Ranchos.

 

UHOH!!!!! Here we go again!!!!!!

 

I have a 32' Sportsmen that probably weighs about 7K on my F250 and do not have the problem you're describing. No ofense, but are you sure you're properly adjusting the equalizer hitch. If you have it too tight, you will put too much weight on the front and actually take weight off the back axel in comparison. The two axles should be nearly equally loaded. Check this by measuring the amount of drop on both the front and rear fender wells as compared to an unhitched state. With my camper, I don't often touch the helper springs either. It just doesn't weigh enough along with the equalizer effect to push down that far. I still have the instructions from Reese that came with my hitch. If you would like, I can scan them or FAX them to you.

 

Uh-oh... I'll save you some searching. I was in the same boat as you, and recently started 3 threads on these topics...

https://www.ford-trucks.com/forums/s...hreadid=111199
https://www.ford-trucks.com/forums/s...hreadid=109564
https://www.ford-trucks.com/forums/s...hreadid=111297

Long story short, the Ranchos are nice, but lack the specific valving. Even their flagship RS9000X series, which I was considering, are not valved specific to the application. As a result, you either get control of body roll/firmness, or dampening of road imperfections/too soft. No offense to the Rancho guys (don't want to start another debate here) but a lot of good marketing pushes the sales on these. Bilsteins are great, valved specific to the application, but are known to be on the firm side. Great if you want performance, not so great if you want a cushy ride on potholes. Either shock is better than stock, though.

After a few heated debates and a wealth of useful information provided by the people who contributed to the threads, I decided on the Edelbrocks. Read the threads especially this one for more info why so I don't repeat the same info here. I ordered them late yesterday, Summit's website shows that they shipped today, so I should have them in 2 days. If the weather is good, I'll be able to do the install and provide an update then. Good luck on your search.