Fifth wheel chucking (practical help needed)

[Mrernestp]

I am in search of some practical (layman terms) help for fifth wheel chucking.
I am relatively new to fifth wheeling and towing in general.
I have a 29 ft fifth wheel with a 11,000 lb GVWR (older so heavier).
My truck is a 2023 GMC Sierra 2500HD. Not full size but longer bed (6’ 10”) I believe.
Curt flex air hitch (for short bed so it has a longer neck.)
Reese 20k receiver
I have horrific chucking! Teeth grinding, mind numbing, coffee splattering, child waking level jolting over bridge seems ect.
I’m talking horrific.
I need help.
I understand (tell me if I’m wrong), that my pin/hitch weight needs to be 20% of the total trailers GVWR (loaded weight).
If my pin weight is that target, and I’m still experiencing this horrid chucking, WHAT do I do?
I’m going to upgrade to a newer and larger fifth wheel at some point, but to be honest I am terrified the issue will remain and don’t know how to resolve this or identify it before buying another rig.
Is it because it’s such a short trailer or causes too much hitch weight?
Is it because the shocks are old and spungy?
Is my stuff loaded improperly inside trailer? (Note it chucks with or without a load and there’s not much rearranging contents even possible in a small trailer)
Any practical information for a novice would be greatly appreciated.

[Thermoguy]

Reading through these suggestions there is not much about the hitch as it relates to the rear axel of the truck. Where is yours, do you have the ability to move the hitch forward or back, up or down?

I have a B&W Companion which has lots of adjustments. When we first got our 5th wheel, the chucking was awful. Our first real camp trip was to Yellowstone, so every night after evaluating the ride, I would adjust the hitch as it relates to the truck bed, forward, up, back, down, etc. Finally found the location where it rides the best and haven't adjusted it since. I do think it rides better with a tank full fresh water, probably takes some weight off the hitch. I have never weighed the trailer separately, only with the truck attached, so can't help you there. But, if you can, try adjusting the hitch in the bed before spending money on shocks, fixes, that might not work.

[laknox]

I remember reading on here years ago, about a guy that got a ticket on I-5 in the Central Valley, for "camping" in the left lane. He took it to court and said that the abysmal conditions of I-5 forced him to use that lane or risk damage to his truck and trailer. IIRC, they had already documented damage caused by road conditions on I-5 and CALTRANS had actually paid off a bill where he'd destroyed all 4 tires and wheels on his FW from hitting a huge crack. Judge tossed the ticket but also suggested that they travel other roads.

Lyle

[jffnkrn]

yeah, yes, uh huh, yeppers etc to all the above.
We have a similiar issue, only on nasty roads, example 89 norht of Flagstaff Arizona. first off, we are loaded and weight distributed pretty good, overall, and extra 1000 lbs available, proper hitch etc. have right at 2000ish on the truck, towing capacity is 14k. So we do two major things. Keep an eye on the traffic in front of us, when you see them fly off the pavement becasue of dips etc, slow down!!! ON roads we are familiar with we just need to keep it slow for a while in the bad areas, maybe all the way down to 40 or so MPH. Good Luck.

[Cummins12V98]

FIRST thing is know your loaded weights. Now what does your rear axle weigh? Look up your weight/inflation chart for your specific tire size and load range. Find the tire weight suggestion for that tire and add 5psi. How does that number compare to the pressure you are running.

I am willing to bet your rear tires are over inflated.

[Durb]

The last two suggestions are good. Shocks on the trailer reduces the tendency of the trailer to rotate. Filling the water tank has two advantages; Causes the truck to squat a little more and reduces the hitch angle plus increases the polar moment of inertia reducing the rotation of the trailer. Higher quality axle equalization also reduces the tendency to rotate.

Towing nose high is a no-no as it increases the hitch angle. The greater the hitch angle, the more chucking forces relative to bouncing forces that are created by the trailer.

Another cheap but not advisable solution is to put on air bags and harden the rear axle of your truck. You would have to pump your pin box to the max. This would cause your trailer not to rotate and would reduce the chucking forces (fore-aft). The problem is the trailer is still generating the forces and they are now being absorbed by the frame plus all the truck generated forces are being transmitted to the trailer frame and its welds.

[laknox]

In my experience, my '02 2500 D'max towing my '04 Komfort 25FSG (29'3" nose to tail, 11,360 GVW) chucked a bit, sometimes pretty hard. I =was= towing nose-high as I needed bed clearance for some of the backroad spots we camped at. My one real regret with that trailer was that it could have used an axle flip to reduce the nose-high attitude, but I never did it. Not sure how much it would have helped, but everyone I talked to said it would. If the OP's FW doesn't have the springs over the axles, that would be a place to start, for sure. Not all that expensive to do. The one recommendation that =everyone= said to do on a flip, was to weld the new spring perches onto the axles or you risk them slipping.

My Komfort did have shocks but, IMO, they were next to useless due to the angle of their attachment. They were nowhere near vertical. Had I flipped the axles, I'm sure they would have been a lot more effective. My '17 KZ doesn't have them, and I wish it did.

FWIW, new shocks on the truck helped somewhat, but not a whole lot.

Lyle

[rhagfo]

Well some stuff I did to reduce chucking,new Bilstein shock on the TV, Shocks on the trailer, leveled the trailer when hitched, and run with a nearly full fresh water tank which is just forward of the axles. We run about 22% pin weight.

[sayoung]

When I had a Reese hitch I found keeping some amount of water in the fresh water tank helped with chucking. But my 5er is heavier .. I allways thought it might of had more to do with the sloppy machining of the jaws on the standard Reese hitch?i went to a BW Patriot and ride much better but found a deal on a used airride hitch. With my AirSafe airbag hitch no chucking/bouncing etc

[Durb]

Unfortunately, all fifth wheels are different and the short ones are more susceptible to generating chucking forces. One thing you might want to check is your Flex-Air pin box. As fifth wheels rotate around an axis and due to the high hitch angle, the pin box pushes down and forward when the tires go over a bump or road imperfection. Check the lower arm of your pin box. If it is pointing down towards your hitch, then it is pushing forward during compression and making chucking worse. Decrease air pressure so it is pointing up.

I too have a 11,000# GVW fiver, 31 ft., and the chucking was horrendous to the point of my wife telling me to sell the trailer half an hour into our first trip. I chose to go with a Trailer Saver TS3 hitch which has geometry just the opposite of your pin box; the hitch retracts when being compressed. Chucking disappeared completely.

You will soon receive comments regarding truck improvements such as shocks; they don't do anything. Your trailer is pushing forward against your frame, completely out of of the suspension vectors.

If you want, private message an email address and I will forward a paper describing what causes chucking and possible solutions. I know it is frustrating; awesome truck, relatively lightweight trailer, and the tow is bad.

[MFL]

Newer truck, older fifth wheel, can cause a nose high tow. If too much nose high, chucking may result.

Jerry

[ReneeG]

Hitch and also the suspension. We have a TrailerSaver BD3 with air bags AND Equa-flex spring suspensions. We boondock a lot taking FS roads, but even on paved roads, we don't have that chucking.

[valhalla360]

Did you take it to the CAT scales to see what the real weights are?

What kind of roads were you on? Was it all kinds or one specific stretch? I know of one stretch near where we live where the joint spacing causes rhythmic bouncing...even just the truck by itself.

My guess is the fancy airbag hitch has something wrong. 5ers are known to pull great with no need for adjustment or fancy add ons.

[Mrernestp]

Western pa (Pittsburgh area). I’ve wondered also about the air bag not working properly. The arrow and line that shows where it should sit hitched is right. So I “think” there is the correct amount of air.
The hitch is mounted with the GM mounting brackets which as far as I understand is the only place on the frame it can go.

[eHoefler]

Check the location of your fifth wheel hitch, It needs to be forward of the rear axle, preferably 4". Since you have a short bed truck, chances are it is centered on or behind the rear axle