Towing a 5th Wheel Can be a Jolting Ride: Upgrade Suspension/Hitch??

[jliebrec]

I have a 2010 F150 Super Crew Lariat 4x4 (5.4 L; 6.5 ft Box; Max Trailer Tow Pkg; 3.73 Rear End; 7700# GVWR Pkg) and a 2011 Forest River Rockwood Sig Ultra Lite 8265S 28 ft length (Dry hitch wt. of 1000; Dry Trailer wt. of 6600 lbs). The truck is rated to pull 11,100 lbs and the payload is rated at 1800 lbs.

On some stretches of cement pavement (US 20 outside of South Bend for example), the truck will experience a rhythmic jarring at 60 mph. Other than that, it pulls just fine in all other conditions with no issues. What can I do to help dampen this jarring felt in the cab? Upgrade the truck rear suspension? Upgrade the 5th wheel hitch? Upgrade the 5th wheel trailer suspension?

Trailer went from factory to home for storage for winter so have time to figure this out.

Thanks for helping a newbie!

[donn]

First problem is probably insufficient suspension on you TV. Second issue is you are using "dry" weights. which are totally meaningless. Load the truck and trailer up like you normally go camping and go to the scales. You will then probably discover your problem.

Edit:
Your fiver has a GVWR of 9100 pounds. So in the real world that translates into a pin weight of around 1800 pounds. If your super crew is loaded like mnost others that means that it is probably ready to camp with the trailer in tow going to scale 9500-10,000 pounds. Way more than a 1/2 ton should be expected to haul.

[Herk7769]

Jeff,

I really don't know where to begin. The "rhythmic jarring" is the least of your issues. Donn's suggestion to "take it to the scales" is with out a doubt your first step. Your springs, front and back, are over their maximums DRY, let alone loaded. The "chucking" you are experiencing is going to destroy your truck over time IMHO.

Use this calculator and your scale visit (for the ACTUAL loads on your truck) to determine what you should do. No "helper springs" or "air bags" made will add GVW capability to your truck.

Fifth Wheel Weight Calculator

I have the IDENTICAL 5th wheel as yours (except branded Flagstaff - 8526RL) and I am AT MY MAXIMUMS towing it with a GMC 2500HD Diesel.

Remember that 15-25% of the camper weight MUST be on the king pin to prevent unsafe towing conditions. Yes Virginia, 5th wheel can be unstable on the highway when there is either not enough weight on the Tow Vehicle or too much. My 2500 is at its max GVW with 16% of camper weight on the pin loaded for camping (and it dances the front of my truck around a bit - my front tires wear much faster than my rears). I have no idea what yours is, but neither do you. You really need to find out.

[Dave_Monica]

By all means, scale the truck with and without the camper to get the real weights as suggested.

The OP says that the truck has a 7700# GVWR, which would give it a real world payload capacity (GVWR less loaded weight) comparable to most 3/4 T diesel trucks, so I don't think payload capacity is at issue with his set-up.

'Chucking' is a common problem when towing on some of the interstates...type 'chucking' in the search line on that other RV forum and read away. Lots of opinions, but in the end, people have spent lots of money while 'chucking is never completely eliminated. The biggest factor is the road itself...uneven sections of concrete that set the 'chucking' motion. I've had it happen once while towing our set-up on I69 in Michigan...I switched lanes to the fast lane and the 'chucking' was gone.

Strangely, we have a section that we travel frequently (I90 in Buffalo) that caused a bad case of 'chucking' when we had the TT...with the 5th wheel, it's not a issue at all. Go figure!

Dave

[Herk7769]

Dave,
My GVWR is 9200 pounds. The truck weights 7800 pounds without the camper. That does include a 180 pound hitch, 150 pound generator, full fuel and family. That leaves 1400 pounds for maximum pin weight.

How you can say, "The OP says that the truck has a 7700# GVWR, which would give it a real world payload capacity (GVWR less loaded weight) comparable to most 3/4 T diesel trucks, so I don't think payload capacity is at issue with his set-up." is beyond me.

Since we have nearly identical campers, we should be pretty close on the camper numbers. My pin weight runs around 16% of its loaded for camping weight of about 8800 pounds. That is about 1400 pounds last I looked.

http://www.forestriverinc.com/nd/def...series=8WideFW

While his unit is lacking the wardrobe slide, the weight difference is less than 200 pounds gross trailer weight.

Seriously, Jeff needs to weigh his truck and rig before connecting and hooked up, to have any idea how to proceed with his problem.
If not, bouncing down the highway will be the least of his worries.

[Itsthetwoofus]

Probably any kind of air ride hitch will help you out. Personally I'd suggest the Hensley Trailer Saver 5th wheel hitch. We have one and tow our 15,500 41 foot Cedar Creek with a 2011 F250 Super Duty with absolutely no pounding, bounce or jarring. Check them out. http://www.hensleymfg.com

[Dave_Monica]

Originally Posted by herk7769

How you can say, "The OP says that the truck has a 7700# GVWR, which would give it a real world payload capacity (GVWR less loaded weight) comparable to most 3/4 T diesel trucks, so I don't think payload capacity is at issue with his set-up." is beyond me.

I say that because his truck probably weighs 5900 to 6000 lbs (mine's 5700 lbs loaded ready to camp, but I know the Ford F150's are heavier). That's a payload to 1700 - 1800 lbs

Dave

[Herk7769]

George,

Jeff has the short bed and needs a slider hitch. That complicates a "hitch based" solution somewhat.

Dave,

I see where you are coming from now. On the surface it sounds reasonable, but...

I pulled up the specs for his truck. 2010 F-150 Supercrew 4x4 Short Bed with 5.4L gas engine and 3.73 rear.
Curb Weight is 5744 pounds empty. (Includes full gas I learned something)

"Curb weight (US English) or kerb weight (UK/Commonwealth English) is the total weight of a vehicle with standard equipment, all necessary operating consumables (e.g. motor oil and coolant), a full tank of fuel, while not loaded with either passengers or cargo.[1][2]

Payload 1540 pounds.
GVWR 7350 pounds.

Curb weight is NO DRIVER, NO PASSENGERS NO HITCH, NO JUNK.

1540 - 200 driver = 1340 pounds left
100 pound hitch = 1240 pounds left (my slide-rite is 200 pounds)
Wife ? another 98 pounds
Dog?
Levelers?
Air Compressor?
Generator?
He had a DRY pin weight of 1000 pounds. What is in the camper?

[acadianbob]

Well, TV aside, it seems that chucking is discussed in many forums and seems to be a fact of life on some stretchs of road. It may be the road and not the TV.

[Herk7769]

From his description, I assumed he meant bouncing and banging.
That could be caused by a bottomed out suspension.

[crocus]

jliebrec, I know exactly what you are talking about, and it has nothing to do with your GVWR and/or/if your truck is overloaded. The jarring you experienced is a back-and-forth motion, correct? If so, an air-ride hitch won't help, as that only softens the up-and-down movement of the camper.
I have experienced it at one time or another with every one of our units, and we have had several combinatons, some hevily loaded, and others well within limits, like our present unit.
It has always been the road that has caused our problems, and it is the joints in the highway slabs, and the lack of staggering in those joints, that causes the rythmic nature of the jarring. I have pulled over and examined the pavement at times, and have seen ridges as high as two inches on some highways. No wonder the rig is complaining!
The effect does seem to differ from rig to rig, and I think it is the distance between the tires, possibly from the rear tires of the TV to the tires on the camper, or maybe the distance between the camper tires themselves. Either way, there is nothing that can be done, other than to avoid those stretches of bad highway, not always an option.
Think of it this way, if your TV tires are on the downhill side of a ridge, and your camper wheels are on the uphill side of another ridge, that will pull the TV and camper apart. Then reverse the situation a split second later, and the TV and camper are pushed together. Repeat every 1/2 second, bang, bang, bang, bang................. I've been there.
While your truck is definitely loaded, I don't see any reason you should worry about pulling that fifth. Unfortunately, I have never found the cure.
p.s. That is a really nice fifth, as we looked hard at the 26-footers before we went to the 28.