Beefing up the springs or adding air bags will change the ride of an unloaded truck. A "spring" system like a Timbren, which I have, leaves the original ride unchanged and only works during a loaded situation. Once the truck "squats" to a predetermined level, it will not settle any more. There are no air adjustments or any maintenance of any kind.

I have a SD Ford and regardless of what trailer I pull, there is no bouncing or handling issues.

Your truck rear tire pressures should be at the maximum capacity as stated on the sidewalls.

Gard

Thanks all.  Got'em ordered to install next week. 

Let us know what you think after you get them.

The Timbrens on our truck are set so the helper springs just touch the blocks when the Timbrens touch the frame. This allows a completely stock ride when empty and a consistent ride level when loaded.

You do not want the Timbrens to interfere with the unloaded ride. It would be an uncomfortable situation.

Gard

http://www.timbren.com/timbren-application-guides/application-pdfs/FR250SDE.pdf

I don't know what's going on but the ride empty is HORRIBLE - very bouncy like I need a seat belt just to stay in the seat.  What did they do wrong when they installed them?  This has to be adjusted...HELP

Update - I've got quite a few trips under my belt with the Timbren's.  The truck isn't sagging hardly at all in the back and when my horse is loaded it hardly bounces at all - pulls nice and straight.

BUT - if the trailer is empty that's a different story.  One person described it pretty clearly that when you have bumps in the road and the truck's back wheels and trailer's wheels hit it at different intervals the trailer bounces and the neck bounces the back of the truck something fierce.  When I took it to have a few things added to it my son actually said he started feeling nauseous from the bouncing.  He was sure glad we got on the highway where the road was smoother.  I have new tires on the truck and trailer, the trailer pulls straight so either there is something with the suspension with the trailer or I need something more on the truck.  I may need new shocks, I have no idea.  A couple of the trailer places thought the air bags would perform better but the mechanic I use thought my shocks were weak.  These are all "thoughts" so until I get it figured out my mare and I will have to deal with the bouncing.  Thank goodness it is minimal to non-existant when she's loaded.

You can actually see the back end of the trailer bounce a bit and then it just back lashes to the back of the truck, that's when you wanna toss your cookies....LOL 

Still not sure how to fix this, I really hate to pull the Timbren's and put air bags on if that's not the cure.  I'd hate to put HD springs on too.   Shocks would be the best solution if that truly is the solution.    I hate this stuff.

Did you remove the spacers?

That's what I've experienced with several of my F150s with extended cab & 6.75 bed (144.5" wheelbase).  Didn't matter if I was towing a BP or a GN... when they are empty, it's wicked -when loaded, it's still bad but not as much. backward and forward tugging.  Did it with the old style suspension and the new (2006 and newer) suspension. 

It's as though my truck suspension would bounce and then the trailer would bounce and put a instant drag on the truck just as it was hitting the next "crack".  I tried running at 80 mph and down to 55 mph (unloaded)... the faster speed was better, but I felt too out of control.

(Quote gabz)... the faster speed was better, but I felt too out of control.

Yea, you were just catching the very tip-top of those expansion joints!!

I only haul 1 horse so it's I doubt it's 12k but i should weigh it to check it out.

What you all are describing is exactly the issue - I've got a short bed f250 diesel 04 (yes the dreaded 6.0) and my trailer as noted is 21' on the floor 28' overall with neck - 7 wide 7'4' tall trailet 3 horse LQ with a 6' short wall.  I don't keep a ton of stuff in it other than my tack and some essentials up front then of course when I go I load up my horse.  I just know empty it's rough and you really need to hold on sometimes.  Stuff in my back tack area was thrown all over when I drove it empty the last time but then I drove it like there was no horse in it too.

I don't honestly know what if anything would fix this.  I guess I just need to take it hooked up to a horse trailer place, let them drive it and see what suggestions they may have. Since this is my daily driver vehicle I'd hate to firm up the ride for that.   

Yes - they took the spacer out of the timbrens - the ride while not hooked up is back to normal.  I know my friend has a chevy short bed crew cab and pulls a similar size trailer and doesn't have these problems.  So it just got me wondering what gives....???

I used to pull a 18' bumper pull previously - never had this problem pulled straight hardly knew it was back there. Didn't matter if it was empty or loaded.

You keep mentioning that it is the trailer which is bouncing when it is unloaded, and that things are better when it's loaded. It sounds as if the trailer tires may be over inflated?

Changing to airbags from your Timbrens should have little affect on the ride of an unloaded rig. While it's unloaded, the Timbrens should not even be touching the frame. Heavy duty springs will make the already harsh ride even more so, loaded or empty. The Timbrens are keeping your ride height correct and contribute to a good ride under a load. They're doing what they're supposed to do.

There are sections of our local roads that cause one of my trailers to start a porpoising action, but not the other. The other trailer has a longer wheelbase, and the cyclic, porpoising motion is not present as a result.

If the truck is being jostled about by the trailer, weak shocks could contribute to the truck's mimicking of the lashing frequency of the trailer. If your truck is a few years old and has some miles, a new set of rear shocks may help. The OEMs generally are not long lived, and the new aftermarket replacements, have life time warranties and generally are constructed much better.

Another thing to check is the tire pressure of your rear tires for correct inflation. They should be OK if you're good under a load, but they may also be overinflated, causing a harsh ride when empty.

Gard

Shortbed Fords are bad about that.  They use soft springs to make it a family or daily driver.  Buy you a set of FIRESTONE airbags and spend the extra money for the incab controller and pump!  I have used them on every truck I have bought.  I have a new Dodge 3500 quad cab c/c with a 12.5-k gvrw and even installed at set on it and keep them at 40psi or so empty and 75psi loaded.  Even made a difference unlaoded on mine. 

 If you install extra springs, you will hate it unloaded it will ride like grandfather's farm wagon.

good luck

c.will_09 - you hit the nail on the head with this one! Ford definately softened up the suspension on these trucks making them great for daily drivers but not so good for hauling with weight on the axle.

I'm still torn between air bags and shocks. The money it would cost to do the air bags with the onboard air is pretty costly and my budget doesn't allow for that right now and would be hesitant to do it w/o the air onboard.

I'm definately not doing HD springs as I don't want to get beat to death driving around town unhooked.  I'm still letting all this "Marinate" while I start saving to get 'er done.  

The 2004 and newer F150s, and then a year or two later they changed the 250/350s, have the super stiff suspension. That's when they moved the shocks...  and right now I cannot remember if they moved them IN or OUT in relation to the springs.  These are NOT soft suspension.  My F150 bounces off a dirt road if I have no load in it. 144.5" wheelbase (extended cab with 6.75 bed).

Maybe getting a newer truck would be cheapest solution?

My truck bounces too but probably got something to do with the 75mph to 80 speed

A newer truck isn't in the picture and wouldn't be cost effective since my truck is loaded to the hilt inside.  I just couldn't afford the 45k it would cost to replace it right now.  $1000 for the air bags with onboard air is definately cheaper.  Even if I (gulp) have to do the HD springs that's 500 bucks, shocks are a little less.

Whenever I DO get to that point you bet I'll be getting a dually either dodge or Ford diesel.  Of course at that point it will NOT be my daily driving vehicle and it'll definately be a long bed.  Then I'll be ready for my next trailer!!

Note - that is interesting about the shocks. I will have to say I checked with the Ford Mechanic and he did advise the suspension is not as firm on the 04's due to alot of people wanting them as daily driving vehicles rather than towing vehicles.  They did change that later on but I'm not sure what year.  My eyes have really been opened to what to look for in my next tow vehicle.    I still like my truck and will have to make it work for now.  I suppose I should look into trading up to maybe a SRW 1ton especially with the economy what it is but I just dread paying on a vehicle that long.