I have a '21 Limited w/HD Tow, CCD, 22" wheels, 285 Cross Climates, 1200 e2 WDH. I'm wondering how to reduce porpoising when pulling my Rockwood 2516. Should i add sumo springs to both front and rear? Does a sway bar change have a larger effect? What are the suppliers of the suspension upgrades? eTrailer only? Thanks in advance for your help.
suspension upgrade with a 7000 GVW travel trailer
- Thread starter ryanpe
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JasonH
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The first step is to visit a scale and make sure the tongue and axles are properly loaded. Once that is confirmed you can try a downsized 20" wheel and "D" or "E" tire with higher pressure. Someone on the forum also obtained custom wound stiffer springs. I would suggest Bilstein struts, but that's not feasible with CCD.
@JasonH Nailed it.
Also, make sure you are engaging Tow Mode. CCD equipped 4th Gens increase the dampening in the rear in Tow mode. It helps.
Also, make sure you are engaging Tow Mode. CCD equipped 4th Gens increase the dampening in the rear in Tow mode. It helps.
I went to a Cat scale and my payload is at 88.1%, front axle is at 89.5% and the rear axle at 93.2% of their respective ratings. The trailer was at 86.2% of max rating. I weighed the tongue and it was at 950 lbs. I always tow in tow mode. It tows great except for some buffeting when semis pass and a little porpoising over dips in the road .
JasonH
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Your tongue weight is high if your trailer isn't fully loaded. If your camper is at 86% of max GVWR, your tongue weight should be between 600 and 900 lbs, say 700 for a good target. This leaves a buffer for water or other items. Try moving any personal items in the front further back.
The manual calls for 50% front axle restoration, so half of the weight removed from the front axle should be returned when the WDH is connected. I.e. measuring from the fenderwell, if the front rises by 1“ when the camper is connected, it should go back down by .5" when the WDH is connected.
Once you get that sorted you can try some stiffer rubber with higher pressure. If there's a Discount Tire near you, see if they will let you try out some 20" inch wheels and D or E rubber for a few days. My biggest towing improvement came from going to 65 psi. It's higher than needed for my load, but the rear feels very planted. In contrast, the previous XL tires felt mushy and squirmed even at their max of 51 psi.
I commend you for going to the a certified scale. You're ahead of 90% of your peers already.
Left Coast Geek
Full Access Members
With 950 lbs tongue weight and maybe another 50 lbs for the WDH itself, you've only got around 500 lbs payload including driver and passengers, if your expy has a 1500 lb payload like mine.
Was the trailer and truck loaded for a typical trip when you weighed it?
My expy has 1605 payload but it was not loaded as much as typical...may 60% of my normal for a long trip. I am thinking of carrying only one of the two 30# LP tanks which would save me 55#. Also, we loaded the trailer with only 45% of the items by weight we pulled from our last trailer (Lance). It was a real learning experience as we camped for over 130 nights and 26K miles with many unneeded items. This new Rockwood has a tone of inside storage that right now it completely empty and I aim to keep it that way. The 950# of tongue was after we loaded the trailer with basically everything we need to head out minus the food.
reklaw
Active Member
I can't believe other people haven't said it yet but I think that your trailer is too much for your Expedition. The max tongue weight on your Expedition, I believe, should be about 900 pounds. If that is the case a weight distributing hitch doesn't mean that you can go over that.
I admit that I don't have much experience with WDH's as I had been towing a popup for over 10 years but I did just upgrade to a 28 foot travel trailer a year ago and got my WDH set up perfect after a few test runs and I don't experience any porpoising or sway.
Now that I think about it, lets say I am wrong about the tongue weight on the Expedition, did you set up the hitch yourself or did the dealer do it? It could be set up wrong causing the issue.
I admit that I don't have much experience with WDH's as I had been towing a popup for over 10 years but I did just upgrade to a 28 foot travel trailer a year ago and got my WDH set up perfect after a few test runs and I don't experience any porpoising or sway.
Now that I think about it, lets say I am wrong about the tongue weight on the Expedition, did you set up the hitch yourself or did the dealer do it? It could be set up wrong causing the issue.
chuck s
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I'm thinking it's wheels/tires and WDH settings. WDH is the easiest to adjust.
Messing with tires and suspension is an expensive game with no assurance of winning. Play with your WDH on a Saturday morning. Lots of trial and error including compensating for the very sloppy Ford drawbar receiver on the back of the truck. I have the most washers I can cram in there to set the angle correctly. (More washers than were furnished.)
GVW of the Rockwood 2516 is 7778 pounds and you need at least 10% of that on the ball but no more than 15% (both for safe towing). That's 778 to 1166 but the maximum weight on the ball for the Expedition is 930 pounds (920?) and you're at 950 -- close.
My Roo is lighter and I think my Equalizer is the 10K version.
My experience with my 7000 pound Roo (since 2005!) and two different Expeditions has been to adjust the WDH to bring the front suspension compression down to close to what it was before the trailer is on the ball while not raising the rear above the same point. In other words the front and rear suspensions compress close to equally -- ain't gonna happen -- but should compress at least a little bit. This restores much of the weight on the steering axle which greatly enhances handling. When I updated the truck back in 2017 the WDH needed no adjustments.
Found the OEM tire size to work best. My stock 275/65-18 are more stable than the bling 20" and 22" tires. I actually would have preferred the tires on my 2007: 265/70-17 for more sidewall.
Too much tire pressure in the tires, trailer or truck, can acerbate this. Oversize tires on the trailer will hammer the trailer suspension if run at maximum side pressure and cause the trailer to jump on every bump. Max placard pressure works.
-- Chuck
Messing with tires and suspension is an expensive game with no assurance of winning. Play with your WDH on a Saturday morning. Lots of trial and error including compensating for the very sloppy Ford drawbar receiver on the back of the truck. I have the most washers I can cram in there to set the angle correctly. (More washers than were furnished.)
GVW of the Rockwood 2516 is 7778 pounds and you need at least 10% of that on the ball but no more than 15% (both for safe towing). That's 778 to 1166 but the maximum weight on the ball for the Expedition is 930 pounds (920?) and you're at 950 -- close.
My Roo is lighter and I think my Equalizer is the 10K version.
My experience with my 7000 pound Roo (since 2005!) and two different Expeditions has been to adjust the WDH to bring the front suspension compression down to close to what it was before the trailer is on the ball while not raising the rear above the same point. In other words the front and rear suspensions compress close to equally -- ain't gonna happen -- but should compress at least a little bit. This restores much of the weight on the steering axle which greatly enhances handling. When I updated the truck back in 2017 the WDH needed no adjustments.
Found the OEM tire size to work best. My stock 275/65-18 are more stable than the bling 20" and 22" tires. I actually would have preferred the tires on my 2007: 265/70-17 for more sidewall.
Too much tire pressure in the tires, trailer or truck, can acerbate this. Oversize tires on the trailer will hammer the trailer suspension if run at maximum side pressure and cause the trailer to jump on every bump. Max placard pressure works.
-- Chuck
