I also have the 6.5 Screw with heavy duty payload package and have never noticed the slightest shudder unloaded or when towing my camper with 1000+ lbs of tongue weight.

The spring pack in the rear does look plenty beefy (my payload spec is 2305 lbs.).

I have read through many of the posts concerning this problem.

I just wonder why not all 6.5 bed standard load Screws show the problem and some other F150's with the shorter bed and some Ext. cab with the 6.5 bed do.

 

No, I think it's more like a "torque arm" that is welded to the rear axle and ties into a joint at the mid-frame. I'm too lazy to look it up though so I'll leave this shrouded in mystery.

 

Lovemybig, a thousand lbs won't do anything for mine either.
Try to load it up close to the max, 2K+ lbs. In that case, I can fell a slight shudder around 5mph on take-off. It is very short, lasts less than a couple seconds. I would call it more of a wobble, and I can make it not do it by letting off the gas just before it happens, and then accelerate slowly to like 10mph or so.

 

Sorry Flixden, I should have clarified a bit more.

I've never had it loaded to the max 2300. That's why I got the package....I didn't want to be running near the limit of the regular payload ones with trailer on, the bed loaded, and wife and grandkids inside. I'm running about 1800-1900 lbs. That gives me plenty of breathing room for any unexpected extra load.

No doubt this seems to be an issue with some models. But the heavy payload package seems to mitigate the issue for the most part, of which I am thankful.

I also wonder if there is a difference in total loaded weight all in the bed, and weight distributed by the trailer hitch. Would either cause the wrap, or just the one weighted in the bed.

At least for my load, so far, so good.

 

I agree, the heavier HD payload springs help greatly, the issue is pretty much non existent, unless you are at the limit with the load (at least for me). I have to say that I am glad about that as well, as I sure would not like that wobble all the time.

 

My thinking is YES. Reason for this is that the 1000# of tongue weight is distributed partially to the front axle and the back axle.

My 2011 6.5 bed SCREW with EcoBoost had the shutter when running empty. I took it in and now it does it sometimes when I am hooked up to our 31' camper. It too has about 1000# of tongue weight and tipped the scales last Sunday at 8640#.

As for the ladder bar and Slapper bar thing.
Slapper bars and Ladder bars serve basically the same purpose. They reduce or stop axle wrap. Ladder bars do not allow it at all as they have a 3 point hookup and are bolted in place. One point of contact on the frame fwd of the rear diff. and two points, one above and one below the axle tube. A slapper bar type traction bar will allow the axle to wrap but limits how much by the bar contacting the fwd portion of the spring. I am curious if the "1978 Z-28" type would help this issue? Roadmaster RAS seems to do the same thing in a different way.

 

some of the old school slapper bars could be adjusted to add some preload, so if you were to use them with the snubber contacting the spring all the time, i bet you would notice a difference.

i would expect some compromise in spring articulation, though. nothing is free, ya know.

as for the tounge weight of the trailer, a weight distributing hitch will help such that it keeps weight from transfering from the front axle to the rear axle.

I don't remember the exact number, but with the long wheel base trucks, something close to 40lbs transfers from the front to rear for every 100lbs put on the drawbar.

so, 1000lbs on the drawbar will put about 1400lbs on the rear axle, without the equalizing bars. so in that regard, they will make a big difference.

 

Very good info.

 

So under full load conditions (ie. - people/gear in truck, WD hitch attached with trailer) the only way I could see to get the actual load on the rear axle would be to weigh only the front axle, then only the trailer wheels and then subtract these two weights from the entire weight of the truck/trailer.

This I would assume, since all the truck scales I have seen are too long to just get the truck rear wheels only.

Am I looking at this correctly?

 

I stopped by a "CAT" scale at a "LOVES" truck stop on the way home last Sunday. They have a split scale with 3 individual scales. You can pull your front axle onto scale #1(front), rear axle on scale #2 (mid) and leave trailer axles on #3 scale. Ask them for a split weight. They will tell you weights on scale 1,2,3. How To Weigh | CAT Scale

My truck is a 2011 F150 SuperCrew with 6.5' bed. I think I could have stretched it to the 3 scales but then could not have weighed just the trailer. Main numbers I was looking for were the Gross Combined weight, Actual trailer weight, and Tongue weight. SO, I pulled my truck onto #2 and trailer axles on #3 with the tongue jack over #3. Asked attendant for a split wt. Jotted down those numbers. Roughly 7400 truck, 7600 trailer. Then I dropped my tongue jack and asked for another split weight. ended up roughly 6400 truck and 8600 trailer. This gave me what I was looking for. ~15K GCW. and the trailer wt of 8600# and a tongue wt of about 1000#. Truck sits level so was not as worried about each axle on the truck. My truck is rated to tow 9600 so with a I am right at the 90% mark and am comfortable with that. We dont tow LONG distance and I tow at 65 MPH or less.

For all three weights twice you will have to weigh all 3, then back up, drop trailer and reweigh all 3. Re hook and go.

 

BigD,

Thanks for the info. I did not realize the scales were actually in different sections. They never mentioned this when I had the truck/trailer weighed in the past. I guess they thought I knew.

I got my tongue weight by using the bathroom scale with a 4x4 method.

But I have often wondered what the actual load on the rear axle was when fully loaded with the proper trailer setup.

Since the scales measure each section separately, I might see if my rig just happens to fit on the three sections with front, rear and trailer.

Thanks again and tow safe. Getting ready to head to Charleston, SC for Labor day. It's about a 7 hour trip, and no fun to have problems while towing. Been there, experienced that.

 

That would work.

 

The longer the wheel base, the less will be taken off the front and transferred to the back, one of the advantages of a longer wheel base for towing.
I don't think it is nearly 40% with our trucks, but I have the numbers at home - I measured all of it just a couple weeks ago when I weighed my rig with trailer. You need to divide the ball overhang (the horizontal distance between ball and rear axle) by the wheel base, and multiply that by the tongue weight.
So as an example: if the ball overhang is 3 ft (I think that's close), then with a 157" wheel base, we have 36/157 = 23%. So with a 1,000 lbs tongue weight, 230 lbs would be unloaded from the front, and the rear axle would be loaded up with 1,230 lbs (with no WD). If the overhang was 4ft, it would be 30%, or 300 lbs / 1,300 lbs. Again, I need to look, I just measured mine a couple weeks ago. I used a closed scale by the hgwy in OR, early in the morning. It was a one axle only scale, the pad was maybe 10ft x 10ft or so. The scale was closed but the overhead display worked - so I was able to take all my time to measure all axles, and even unhook the trailer, and measure with and without WD applied. That was kind of a cool exercise, I learned quite a few things!

 

That was very handy!!!

At the Loves I stopped at. The operator gave me Verbal numbers. She asked was verbal good enough or did I need a print? I said Verbal is fine. When we were done... She said OK, Your good to go!! Did not charge me for it. As I understand its only about $10.00 even if you have to pay.

The next time Im passing thru that area... That Loves will be my stop of choice!

 

I just looked at my measurements, and meborder is right: it is almost 40% that is taken off the front.
My ball overhang is 59", and with a wheel base of 157", that's 157/59 = 37.5%