Porpoising

New or heavier shocks, heavier springs might help

Hit the bumps slower:B

As mentioned, you could probably do some suspension work (shocks, air bags, helper springs), though you would probably change the feel of the ride when you are not going over bumps (most of the time, I assume), so not sure if you really want to make the changes.

What is the air pressure in your tires? Is it set at the recommended pressure for the weight on them? Or did you just "max" them out at the recommendation on the side of the tire? Over-inflated tires will give a rough ride too.

Good Luck:)

Moved to Class C.

Try trimming the motor/drive down...oops, thought I was in a boating forum :)

Have you tried varying speeds? Sometimes the wheelbase and speed combination make the porpoising worse...I've not really noticed any with our mh but did with previous 5'er and, with it, sometimes a slightly slower or faster speed would lessen it.

They all do it. Lots of 'C' behind the rear wheels. But a rear kitchen has a lot more stuff that can fall. Mine is a rear BR. When I first started, everything on a hangar in the closet was on the floor when I stopped for the night. I finally bought a spring loaded drapery rod that I put over the top of the hangar hooks before driving. Not much to fall, anyway. I don't put jeans and T Shirts on hangars to begin with. I do the same thing for the shelves in the bathroom medicine chest.
In your case with a rear kitchen, you just have to put everything in a drawer before driving. If stuff rattles, go to Home Depot, Lowe's or an auto supply shop and buy a bundle of orange rags like mechanics use to wipe their hands and stuff them into the open spaces. Cheap, and easy to find and remove when you stop for the night.

Go weigh your rig. Then set your tire pressure to what your chart calls for its weight. Do you have air bags? That can also effect ride.

I had a porpoising problem on my 2006 Chevy based Class C also. The stock shocks are not up to the job.

Changing the air pressure will do no good at all. What is needed is a good pair of shocks to stop it.

Like a good set of Bilsteins LIKE THESE from E Shocks. They have the best price around.

After they were installed all the porpoising went away.

Good luck with this.

I hear Koni is making available their class-A FSD shocks very soon for the E350/E450. They are soft when can be and go into heavy-duty mode as road conditions dictate. It is internal to the shock, changing instantaneously.

CLICK HERE to read about the technology.

CLICK HERE to watch a short video at an RV show. A Koni rep mentions the benefits on Class-A rigs.


I would hold out and get them.

IAMICHABOD wrote:
I had a porpoising problem on my 2006 Chevy based Class C also. The stock shocks are not up to the job.

Changing the air pressure will do no good at all. What is needed is a good pair of shocks to stop it. I might agree with you depending on what the original poster is describing. I, however, thought he was describing a harsh ride. Changing shocks would help a continual bounce. A harsh ride often is due to tires inflated to carry maximum load. A light load will give you a rough ride. Tires are also part of the suspension system and thus the ride. Imagine what your ride would be like if you had hard rubber tires? My tires are rated to carry 9,890 lbs on the rear when inflated to 80 psig. If inflated to that, would produce a very harsh ride. My rear axle only weighs 5,760 lbs so the tires inflated to 40 lbs would support the 6,000 lbs. That's a big difference.

Like a good set of Bilsteins LIKE THESE from E Shocks. They have the best price around.

After they were installed all the porpoising went away.

Good luck with this.

My comments in Red. :)

I have a 21 foot chev motor home with the rear kitchen. My fresh water is under a cupboard and I travel with it full. Mine does not porpoise at all.
I have the old shocks and she rides nice. My specified tire pressure
is 55 lbs. See what the inside of the door jamb states for tire pressure.
The stuff on my counter top stays there during the ride.

Brian