Porpoise Type Ride

[jstorey1956]

I have a 2016 Rockwood Signature Travel Trailer, pull weight approx. 8300 lb. I am pulling it with a 2015 Silverado High Country, 6.2L Engine, it is rated to pull 10,000lbs.

While the truck pulls the camper without any issue, when going across those spots on the road that is a dip or rise, the up and down motion is more severe than it should. The truck is not bottoming out, but my stomach is...

Any one have suggestions for firming up the backend while pulling the camper?

[RDMueller]

I was initially towing without a W/D hitch because my truck was capable of doing so. However the ride was much like you describe which led me to buy an Andersen no sway no bounce hitch. The difference was huge! Not sure if other W/D hitches do as much as the Andersen for bounce.

Also, you may want to check out the sticky at the top of this (TT) forum regarding the Dexter HD suspension. I just finished reading the whole thing and it sounds like many people say it significantly improves the ride. Personally after reading that thread, I'm sold on it and it will be the next upgrade on my TT, definitely before our long trip this summer.

[Community Alumni]

The bad part about AL roads is that they can be pretty rough even when everything is setup. The good part is that the passenger (wife) starts to provide plenty of entertainment from over there lol.

First verify with a CAT scale that your WDH is setup and transferring weights correctly to the front axle. This is free (well besides for the cost of scale tickets). If everything is setup correctly then I would move on to upgrading the suspension.

Timbrens or Firestone Work Rite can help. They are just really big bump stops and unloaded they are not engaged. When you load up, they engage and function as sort of a progressive springs that ends up taking some of the travel out of your factory springs. Bilsteins help even more by helping slow down the oscillating cycles of the suspension.

Generally, half ton suspension are designed towards a softer side, so they don't handle heavy loads very well. A 90 lbs person in the bed of my truck can start engage the rears. I've done Bilsteins and Work Rites and it's pretty solid back there now when hooked up. Not too stiff, but nice and stable.

[silverfz]

You also have given ideas from free, adjusting wdh to new shocks which are a few hundred to the classic alot of thousand option of getting a new truck.i would weigh your setup and start at the cheapest and go up. At some point the law of diminishing returns starts.

[93Cobra2771]

As you are seeing, a lot of factors can cause it:

Too much tongue
Too little tongue
wdh set to tight
wdh set to loose
harmonics from road
shocks

Now its up to you to do the scaling and investigation and figue out what it is.

[Walaby]

Thanks Boband4. I assume it is the same as GAWR-Front. Just never heard it referenced as that.
EDIT: Thanks Ron - Learn something new every day.
Mike

[Ron_Gratz]

Boband4 wrote:
What is FALR? That's a new term to me.

Front axle load rating. I had to google it!

FALR, in this context, stands for Front Axle Load Restoration.

If tongue weight causes 500# to be removed from the front axle, and

if application of WD causes 200# to be restored (added back onto) to the front axle, then

the FALR is 200/500 = 40%.

Ron

[rbpru]

Twice I have hit the Porpose bounce. The first time it was the road and I slowed down. The second was the WD hitch was one link too tight for the load.

I also up my tire pressure from the recommended 32 psi to 40 psi whenever I tow or load the truck heavy.

[Boband4]

Adjust the WD hitch to achieve close to 50 percent FALR and see how it handles then. If still experiencing unacceptable ride, I would then adjust up the WD to achieve a "slightly" higher FALR ( maybe increasing it to 60 percent ), then re-evaluate. At no point in this process of experimenting would I go over 100 percent FALR.

What is FALR? That's a new term to me.

Front axle load rating. I had to google it!

[mobeewan]

I've had your same problem. Porpoising is usually caused by not enough weight at the toungue. On uneven pavement the light tounge is pulling up on the rear of the tow vehicle when the bounce occurs. I have had to move things in my trailer to the front a couple times coming home with a full black tank & empty FW tank. BW tank is near trailer bumper & FW tank is 3 ft in front of the axles.

[CampingN_C_]

We need to know what hitch and it's rating that you're running.

[Dog_Trainer]

When I towed with my 1/2 ton (Flagstaff Ultralite) TT weighed in at 8700 Loaded,wet and ready to go, I did alright with E rated tires, Timbrens and Bilsteins. But no matter what you do you will still be towing a pretty heavy load with a light truck. My payload was about 100 lbs under the max. I would imagine you will have 1600lbs + in payload and that may be overloaded for your truck. Then there is the question about what the rear gears are. Towing near the limits really dictates that you know all your weights.
My best move by far was to step up to the 2500 series truck.

[westend]

Yeah, get thee to scale so you know what you have. As ktmrfs said, shocks will help. WDH adjustment may help, too.

The bad news is that there are certain sections of concrete roadway that have cupped at certain intervals in sections. These set off a harmonic imbalance between truck and towed trailer.
Changing speed to get out of the intervals helps but there may just be a lot of pitching no matter what you try because your combination enters these bad sections at typical speed. Try increasing/decreasing your speed 5 mph the next time you haul through the bad road.

Known "porpoise pen"------I94 South, a few miles from St. Joseph/Collegeville, MN. I think they may have repaved some of this. I haven't been through it with trailer for awhile.

[DoubleEagle]

A set of Timbrens and upgrading to LT tires significantly reduced the occasional porpoising I experienced; I scaled my rig to verify I was within limits prior to the upgrades.

[Walaby]

gmw photos wrote:
Adjust the WD hitch to achieve close to 50 percent FALR and see how it handles then. If still experiencing unacceptable ride, I would then adjust up the WD to achieve a "slightly" higher FALR ( maybe increasing it to 60 percent ), then re-evaluate. At no point in this process of experimenting would I go over 100 percent FALR.

What is FALR? That's a new term to me.

I get the porpoising effect on concrete sections of the freeway near my house. Regular asphalt smooth ride, so definitely the road construction does have impact.

Mike