"Bucking" 5.0TA - Sierra combo

[PM15283]

Returned to MN from wintering in AZ over Easter weekend and love our new 2018 trailer. This was the first long drive since going to AZ from Br. Columbia last November.
Found our towing mileage to be around 10 mpg at just under 70 mph and 14 mpg at 62. Chose the latter speed and arrived safely at home.
Unfortunately, several (many!) stretches of road caused a severe bounce of truck and trailer. Speeding up to around 70 completely eliminated this bucking. I've been advised to change to adjustable shocks (four or rear only?).
Truck is a 2014 Dbl Cab 1500 5.3 V-8 w/rear airbags and Andersen Hitch. (Bags remain from a departed Jayco)
Any advice appreciated.

Phil Murray

[Jim Bennett]

I would have to assume your issue is truck related, maybe shocks like you mentioned, or maybe springs? I just know that there is almost no porpoising action with our 5.0TA . There is a very small amount on bumps or dips that are big, but in general and at any speed, there really is nothing.

[escape artist]

Hi: PM15283... Make sure you tow with a full fresh water tank. Alf
escape artist N.S. of Lake Erie

[Eggscape]

I installed air bags on an old pickup and it completely changed the ride. Still had the leaf springs but the bags provided a little extra bounce that the shocks did not control well.

I would think the bags may be the problem and to use as little air in them as you can. New HD rear shocks are a good start as well.

[cpaharley2008]

and please update your avatar to show the correct Escape trailer...

[Brian B-P]

This is typically a resonance problem, meaning that the combination of bump spacing (which is very regular in some concrete highways) and truck wheelbase produces a frequency which makes the truck buck like a pendulum swinging or a tuning fork vibrating. Changing the stiffness of the springs changes the resonant speed, any change in speed (faster or slower) makes it stop, and more damping of suspension motion (which means stiffer shock absorbers) reduces or stops it even at the resonant speed. The mass of the attached trailer will change the resonant speed too, so you won't likely notice it at the same speed without the trailer.

This will vary greatly between trucks, even of the same make and model, due to differences in wheelbase, springs, shocks, and tires... even counting only factory-available options.

Since the air bags have changed the truck's rear spring rate, the most straightforward solution is to change only the truck's rear shock absorbers.

Increasing suspension damping in the trailer would help, too, but the only way to add damping to the trailer suspension is to have custom brackets made so that shock absorbers can be added. This works (and has other benefits), and is well proven on Airstreams, on trailers with similar suspensions in Europe, and with custom installations on other small trailers; however, no one does it on any Escape trailer.

[Ronn]

Originally Posted by PM15283

Returned to MN from wintering in AZ over Easter weekend and love our new 2018 trailer. This was the first long drive since going to AZ from Br. Columbia last November.
Found our towing mileage to be around 10 mpg at just under 70 mph and 14 mpg at 62. Chose the latter speed and arrived safely at home.
Unfortunately, several (many!) stretches of road caused a severe bounce of truck and trailer. Speeding up to around 70 completely eliminated this bucking. I've been advised to change to adjustable shocks (four or rear only?).
Truck is a 2014 Dbl Cab 1500 5.3 V-8 w/rear airbags and Andersen Hitch. (Bags remain from a departed Jayco)
Any advice appreciated.

Phil Murray

Quick Question Phil, in another post you mentioned hauling a small trailer back, was that the case and if so might that have had an affect?

[PM15283]

Really doubt it. That trailer weight is less than 300 lbs, I think. (Less, but I put some firewood in the front to give some weight to the tongue.)

[akmacs]

Do you have a picture of your andersen hitch mounted in your truck?
I use the andersen ultimate hitch also along with a B&W turnover ball and I would forget the trailer is there many times if I didn't see it in the mirror.

My first thought would be you don't have enough weight forward on your trailer but I wouldn't expect it to make your truck "buck".

[PM15283]

Originally Posted by akmacs

Do you have a picture of your andersen hitch mounted in your truck?

I use the andersen ultimate hitch also along with a B&W turnover ball and I would forget the trailer is there many times if I didn't see it in the mirror.



My first thought would be you don't have enough weight forward on your trailer but I wouldn't expect it to make your truck "buck".

Agreed - when all is smooth it's a beauty!

[PM15283]

Originally Posted by cpaharley2008

and please update your avatar to show the correct Escape trailer...

Sorry, and done!

[Chotch]

Is your trailer level when towing?

[PM15283]

Originally Posted by Chotch

Is your trailer level when towing?

Not sure, but as set up at ETI. May be slightly nose up.

[Chotch]

I'd get the trailer level before doing anything else.
Important for dual axle trailer.

[Brian B-P]

Originally Posted by PM15283

Not sure, but as set up at ETI. May be slightly nose up.

While perfectly level is ideal, if you're a little off nose-high is better than nose-low (with tandem axles like this trailer).

[Perry Butler]

Originally Posted by PM15283

Not sure, but as set up at ETI. May be slightly nose up.

Even though we purchased the 2 1/2" lift kit, and ETI was informed of the bed/rail height of our pickup well in advance, they installed the hitch on the 5.0 in the wrong position. On the trip home we were 1-2" high, but lower in relationship to the truck bed. It may have looked level, but it wasn't level.

After we got home I tried to put our trikes in the bed of the pickup and there wasn't enough clearance. In the dead of winter, in a foot of snow, I had to move the 5.0's hitch to the upper holes and the Andersen hitch to the upper holes. This actually lowered the front of the camper (the hitch on the camper was raised higher than the ball hitch on the truck) The trikes cleared the hitch and the 5.0 is now perfectly level.

However, this summer I have to paint the ugly holes where the lower bolts went into the camper portion of the hitch.

Food for thought.

Perry

[cdmixer]

I am brand new to camping so I am expecting Escape to put the E2 by fastway on my new GMC Seirra 1500. My truck has the basic trailer towing package as well as a trailer brake installed but I have no ball yet. Do I trust escape to put this on right since I know nothing about this type of hitch system. We also got the lift in the trailer option.

Thanks.

[John in Santa Cruz]

do NOT use 'sports performance' shocks with proportional valving like Bilsteins, rather, you want simple single stage shocks like Rancho 6000's.

question, is your '5th wheel' directly over the axle, or is it fore or aft? I've heard that can affect things.

[grantpallen]

Just went through the same experience. Had airbags put in but really made no difference. Dropped by escape and mentioned to him I thought the nose was up too high. When measured I found the nose was up 4 1/2 inches higher than the rear. By adjusting the head on the fifth wheel it lowered it down to To almost level. The bucking stopped. So glad to have found the solution to my problem.

[mizterwizard]

There are a lot of good ideas here. Lots to check out. Here is a little more to consider.

When the trailer tips forward or backward the weight moves in the direction of the tilt. If it is nose high it will also be nose light. These trailers already run a bit light in the front compared to many stickies. The rule of thumb for stickies is 25% tongue weight but many FGRVs run closer to 10%. At some point the wind resistance and aerodynamic lift will counter the tongue weight and it will balance on the rear axles. Faster and the trailer will lift on the truck. Slower and it will push down on it. Balanced gives more opportunity to for any slack to let it buck up and down or forward and back.

With the hitch setup you have there should be almost no slack in the setup. Check that everything is as it should be. If you find any slack, see why it is there and eliminate it. Perhaps you don't have the Anderson hitch properly pulled down on the goose neck ball?

Truck manufacturers know that most of their trucks will spend almost their entire lives empty. I know a guy who's sprayed in bed liner still looks like it was done last week after nearly 20 years. Manufacturers also know that people like a truck to ride like a car. Because of this they tend to have limp shocks which work okay empty but don't have the power to handle much more load without under damping. Better shocks would help for sure.

I also frequent a truck forum. There they like the Bilstein shocks much more than the Rancho's. I can't advise you directly but I think either one would help.

Shocks on the trailer would help some but the torqueflex type axles don't need it nearly as much as leaf spring axles. The deadness of the suspension rubber in torqueflex axles does a lot of damping on its own.

Either remove the air bags or keep at least 5 psi in them or they will be damaged internally and become useless. Air bags have no damping at all. The leaf springs on your truck have a little damping due to the springs rubbing against each other. The more weight the air bags carry the less damping you will have in the rear.

Shocks should ideally be balanced between the front and the rear. By balanced I mean that the amount of damping relative to the amount of load they handle should be the same. Empty the truck is front heavy. Loaded with a 5.0TA they should be nearly equal. If you have stiffer shocks on one end than the other while loaded it could lead to less than ideal handling and ride.

I think the first thing to try would be to move some weight to the front of the trailer. A couple of hundred pounds could make all of the difference.

If your alignment is off it could make a difference in ride too. Both the truck and trailer need to have all wheels standing upright and pointing in the same direction. It would be worth running a string along the side of the rig and see what it all looks like relative to a straight line.

Just some things to consider.