New 5th Wheel Rough Ride

[hazmat456]

It is the torsion axles. Without a equalizer, the axles cannot "talk" to each other. Think what happens when going over a bump or depression. The trailer will travel half again as far up or down as with a leaf spring axle. That will not encourage a smooth ride. Independent suspension should never be installed on a camping trailer.

[DieselDrax]

Originally Posted by hazmat456

It is the torsion axles. Without a equalizer, the axles cannot "talk" to each other. Think what happens when going over a bump or depression. The trailer will travel half again as far up or down as with a leaf spring axle. That will not encourage a smooth ride. Independent suspension should never be installed on a camping trailer.

My trailer has torsion axles and no such problem, so...

[Daniel.mullins4]

Torsion axle went bad, replaced with the Timbren tandem axle, had no bounce problems to this day. https://timbren.com/p-35854-silent-r...uspension.html

[hazmat456]

Originally Posted by DieselDrax

My trailer has torsion axles and no such problem, so...

Maybe you actually have axles rated above your trailers capacity, most do not. When a torsion axle is near of above its limit, it gets really bouncy. I have had one camper and one equipment trailer with them. When either was above 80% the tire wouldn't spend much time on the pavement.

The exception being single axle trailers, they wont load up the second axle and start bouncing, because there isn't one.

[aceinspp]

Only problem I've had with towing and my 5er has Endurance tires is when you hit extremely rough roads and I do have a Anderson hitch and a 2500 Ram with air ride suspension. I do not exceed 62 mph when towing and and faster will cause you ill effects. Later RJD

[DieselDrax]

Originally Posted by hazmat456

Maybe you actually have axles rated above your trailers capacity, most do not. When a torsion axle is near of above its limit, it gets really bouncy. I have had one camper and one equipment trailer with them. When either was above 80% the tire wouldn't spend much time on the pavement.

The exception being single axle trailers, they wont load up the second axle and start bouncing, because there isn't one.

Keep in mind the axles don’t need to be rated for the trailer GVWR, so if you’re thinking they do then that is where you’ve gone south.

I actually have two trailers with torsion axles, our hybrid and our horse trailer. The hybrid has a GVWR of around 5,600LB and for long trips it’s loaded to 5,000LB (scale weight). Tows great, no bouncing. I’ll have to check and see what the axles are rated for. Quite unlikely they’re 3,500LB axles.

[corn18]

It looks like from the pic in your signature that you have the Andersen set up to push the trailer aft. I did that too and had a bouncy 5er. I switched the Andersen adaptor to move the trailer forward and that helped a lot. I can’t do 90 deg turns now but haven’t found the need to.

[Worthmo]

Originally Posted by corn18

It looks like from the pic in your signature that you have the Andersen set up to push the trailer aft. I did that too and had a bouncy 5er. I switched the Andersen adaptor to move the trailer forward and that helped a lot. I can’t do 90 deg turns now but haven’t found the need to.

You are referring to the king pin coupler? I've been wondering if that would help and have thought about spinning it around. Andersen does not say this, but I feel like that would add more weight to the bed of the truck.

[cc102bob]

Originally Posted by Worthmo

You are referring to the king pin coupler? I've been wondering if that would help and have thought about spinning it around. Andersen does not say this, but I feel like that would add more weight to the bed of the truck.

Would you be able to use the turning point hitch feature on your trailer rather than the Anderson setup to push it back farther? I don't know if the turning point hitch works properly with the Anderson ultimate hitch but it may be worth investigating. the turning point hitch feature on your trailer allows the trailer to be used with a short box pickup and it puts the pivot point further back so you can still make Sharp turns.

Edit:. I just did some googling and discovered that the Anderson ultimate hitch cannot be used with the turning point hitch feature on the trailer. I guess that option is out.

[corn18]

Originally Posted by Worthmo

You are referring to the king pin coupler? I've been wondering if that would help and have thought about spinning it around. Andersen does not say this, but I feel like that would add more weight to the bed of the truck.

No added weight to truck. I have weight chits to show this.

[Worthmo]

Thanks corn18. That's strange that moving it forward didn't change the weight but helped with the bouncing. I'm going to give that a try this weekend but I'm very curious on the physics behind the change.

[corn18]

Originally Posted by Worthmo

Thanks corn18. That's strange that moving it forward didn't change the weight but helped with the bouncing. I'm going to give that a try this weekend but I'm very curious on the physics behind the change.

Me, too. The only thing I can come up with is the total length is shorter. I wish I knew the physics, though. All I know is what I felt in the truck.

[Aeross]

Bhrava - the added front axle weight was 2 more passengers in the truck. I did add 500 lbs. to the pin (water & salt bags) which did help a little but not enough.

[jd4010]

One of the best investments we ever made was changing our our hitch to a Trail Air. Our F350 rides hard (to be expected for a 1 ton dually) and whatever those rear tires hit (e.g. potholes, etc) was transferred directly to the RV until we got the Trail Air. LOVE IT, LOVE IT, LOVE IT!

[Aeross]

Is the Trail Air you are referring to a pin box with air suspension? Unfortunately, this Rockwood 2891BH unit has a Turning Point Trailair pin box (without any airbags or shocks) and according to the manufacturer it can't be replaced or upgraded.

I did swap out the truck hitch and installed a Hensley Trailer Saver and that does a great job of isolating the truck from the 5th wheel, but the problem of 5th wheel excessively bouncing still remains.

[Bhrava]

Originally Posted by Worthmo

Thanks corn18. That's strange that moving it forward didn't change the weight but helped with the bouncing. I'm going to give that a try this weekend but I'm very curious on the physics behind the change.

Wont be much change when weight placement is within a few inches of the axle centerline. Move it a foot in front and then you will see more weight on the front axle, but whether it is 6" in front or 6" behind the weight change is negligible. This is how Anderson can get away with their offset hitch.

Originally Posted by Aeross

Bhrava - the added front axle weight was 2 more passengers in the truck. I did add 500 lbs. to the pin (water & salt bags) which did help a little but not enough.

That makes total sense then, Thanks for the update.

Those who have this bouncing issue, do you know the exact pin weight and can get the percentage of distribution? What might also help is to find out the split between the two axles to see if one has more weight than the other. This can cause bouncing as well, especially if it is a rear axle, the the front is hopping more and you feel it in the truck.

If you look at a horse trailer, the front axle will have more load on it than the rear, and I know mine rides smooth as silk empty, with one horse, or two. Then again they are matched 3500 pound axles for a 7000 GVWR trailer. Another possibility is the axles are too stiff for the trailer.

[Worthmo]

Originally Posted by Aeross

I did stop by the scales to independently weigh the truck and RV. Here are the numbers (and this was before I added 500 lbs weight to the front):
Truck only: Front Axle: 4,940, Rear Axle: 3,740, Gross: 8,680
Truck & 5er: Front Axle: 5,160, Rear Axle: 5,680, Trailer Axles: 9,800 Gross: 20,640

Looks like Aeross came in at almost 20% pin weight. Then he added an additional 500lb after that weighing.

I feel like most of the suggestions for fixing these issue are really caused by extremely bad design of the camper. If it were the design I would also expect everyone that has the camper to have the issue. My friend had a volante with a 17% pin weight and he said it pulled great and no bounce. Most of the campers that I looked at before purchasing had a pin weight between 15-17%. I understand everyone loads their camper differently but I shouldn't have to figure out how to add an additional 2k lbs to the front of my camper in order to drive it without bouncing.

[JRHERE]

Are not most short box 5th wheel hitches sliders? Pulling that hitch weight behind the drive axle is quite less than ideal.
Moving the pin forward will add weight to the steer axle. Slightly lessen the drive axle gross. And lessen the pin leverage on the truck. Pulling behind the axle seems similar to pulling a heavy tag along without the spring bars?

[JRHERE]

As I've said (don't mean to be redundant) before. Pull the trailer with a long bed, properly located hitch and see what happens. Rule out the truck. Ideally pull with a ton LB. If it rides OK, your truck isn't setup right for the trailer.

[Harkerr]

My hitch pin is set 1 inch ahead of the rear axle. The hitch is a PullRite auto slider. Pin weight is about 2200 pounds. Ride is good as long as road ok. Rough road forget it