Harsh ride & chucking…please help me figure it out! (Long)

[Garyl53]

Hi,
Here is my current truck and trailer info along with suspension enhancements:

2011 F250 Super Duty, 6.7L PSD, CC, SRW, Camper Package, Snow Plow Prep Pkg. with Lower & Upper Stableloads, new Bilstein 5100 shocks, Husky 16K W hitch (Center line of king pin about 4” ahead of axle)

2007 Keystone Challenger 29RKP with Reese Sidewinder (SWW-04 wedge for Husky hitch), Dexter EZ-Flex, Lippert Shock Kit, Lippert Correct Track II (recent professional alignment done), new tires

Here are my CAT scale results:
F250 6.7L PSD 4X4 Lariat - Full tank, Husky 16k W hitch, me:
Steer Axle - 4720
Drive Axle - 3300
Total - 8020

With 2007 Keystone Challenger 29RKP under tow:
Steer Axle - 4740
Drive Axle - 5980 (vehicle total=10720)
Trailer Axles - 7780
Total - 18500

Trailer:
Pin Weight – 2680 (25.6%)
Axle Weight - 7780
Total - 10460

About 700 over published tow vehicle GVWR (10000) but...
1320 under axle ratings 5940 (FGAWR) + 6100 (RGAWR) = 12040) and 5000 under GCWR.

I purchased this 5th wheel and truck (used) last summer but despite several suspension improvements on both truck and trailer I continue to experience severe chucking. I am using the term “chucking” here to mean the feeling of a push/pull (or forward/rearward) motion on the truck which creates a very uncomfortable ride. The chucking is always present with the exception of climbing a steep grade (>4 percent) but of course it varies substantially in intensity depending on road conditions, road slope and speed. It does not appear to be directly related to road conditions as it can become severe even when driving on flat and very smooth newly paved asphalt roadways at speeds between 50 and 65. A recent 150m trip had very severe chucking (the FW tank was empty) but that night I fully filled the 50 gal. FW tank (located just ahead of the front axle) and it reduced the amplitude of the chucking somewhat but it was still very much present the next day and still very uncomfortable. I adjusted the pin box to level the trailer frame within 1” front to back. I checked the king pin movement in the hitch and it appears to be minimal (< 1/4 in.). I even operated the Sidewinder pin box in a fixed configuration (service bolts installed) just to eliminate that factor but no change. I added shocks to the trailer which I could visibly see made a huge improvement in the ride of the trailer itself and I had the trailer axles aligned by a professional shop but this had little or no effect on the chucking. At this point I don’t know what to try next. I know there is the option of an air or rubber pin box or an air hitch but my gut tells me there is something wrong with the set-up and I am not convinced I wouldn’t be just covering up a problem or risking a fair amount of cash without fixing the issue. I also realize I am a bit over the GVWR of the truck but there appear to be many, many RV.NET members running similar weights that don’t have this issue.

- Should I try adding additional weight to increase the pin weight more even though it is already 26%?
- Is there too much pin weight? Can I load weight in the rear to see if this helps?
- Is it the truck or trailer causing the issue? How can I determine? Could it be a truck suspension issue?
- I am riding on the truck overload springs when loaded… should I opt for air bags instead?
- Can the Husky Hitch be bad? What else should I check? (All bolts have been torqued to specs)
- Is it just a bad combo of truck and trailer?
- Picture



Any and all suggestions are very much appreciated and I will report back any results. We can’t live with this as it is for anything longer than a few hour trip.
Thanks in advance!

[ACZL]

For starters, it looks like the rear end of your truck in pic sits awfully low w/ camper hooked up. King pin is 4" ahead of axle? IMO, that's too much. Should only be couple inches. I have a 5th Air Borne hitch on 5er and Reese 16K non slider w/ 4-way pivot head and don't get much in way of chucking ( had this exact set up on our '03 F250 SD as well as w/ current truck) Our pin wt was no where's near yours despite a heavier coach overall. Now here's a thought. What is the measurement of the king pin itself? You mentioned you bought the set up used. It's possible that being an '07 coach the king pin could be worn which would cause it to be sloppy in truck hitch. (sorry just re-read where you measured that). Jaws themselves on hitch may be worn (adjustable---IDK as I'm not familiar w/ the workings of that hitch). Weights are a tad high on truck ,but nothing too outrageous.

Do you have a local RV dealer that you have a good report w/ service dep't? NOT CW. Ask the techs for advice as well or have them go w/ you on short ride. Keep us informed of your results.

[grampscamper]

I have a very similar setup. I started with a manual sliding Husky hitch and standard pin box. On occasion I would get chucking but not as bad as you describe.
I replaced the sliding base of the hitch with a fixed base, replaced the pin box with a Mor/ryde, added air bags to my truck and adjusted the pin box so I'm just slightly pin high. I made each of these changes over the last three years. Every change made some improvement.
I still get a little chucking on rough roads but nothing that bothers me.

[Durb]

We too had a perfect chucking storm on our combo to the point where the wife said "sell the trailer" an hour into our first trip. My first thought is you might be nose high but it doesn't look like it on the photo. Keep in mind that your hitch is a solid joint and all pin forces generated by your trailer are transmitted directly to the frame of your truck (the same frame your seats are bolted to). An air hitch will serve to dissipate most of those forces.

Our solution was to buy a TrailerSaver TS3. The trailer now merrily bounces around on its own with little force transmission to the truck. When you hit a bump you will still feel a jolt into the truck almost identical to when the truck is not towing. You can't feel it when the trailer hits the same bump. Can't see myself ever using any other hitch. The smiles start when you leave the driveway.

[ReneeG]

We too have a Hensley TrailerSaver, but it's a BD3. No chucking. See my signature for TV and FW. The marketing slogan is so true, "The name says it all".
The hitch does make a difference, but not the fact that you may be overweight. We towed this same FW, but with an F250 SRW before purchasing our current TV, same hitch. No chucking.

[lakeside013104]

Had similar issue and wife was considering NOT to ride while towing any longer. Switched to Hensley TS3 air bag hitch and chucking stopped completely. We have towed 11,000 comfortable miles. 2011 F-350 towing 2014 Bighorn.
Worked for us. Good luck.

Lakeside