Butt sag when towing a boat...Help | Ford Explorer Forums - Serious Explorations

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Butt sag when towing a boat...Help



Has anyone used coil-over shocks, air-shocks, or air bags on a explorer to solve butt sag? When I tow my boat the rear drops about 3", then add vacation gear in the back and it gets worse... any suggestions?

p.s. hitch weight on the boats is about 150.

98 XLT V8

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Are your shocks stock? The stock ones are not designed for towing heavy loads, that's why the rear sags.

There are several solutions:

1) Get new shocks, heavy duty units. There have been a lot of discussions on which, try a search and you can make your decision after reading the discussions.
My opinion - The Rancho RS9000 is a five-way adjustable shock and can adjusted for heavy load.

2) Get rear air springs (Air Lift bags)- basically uses compressed air bags that help support the additional load.

3) Get spring helpers, similar to add a leaf.

Check out (dead link) they have all the items I mentioned above and more.

[This message has been edited by kvo (edited 08-25-1999).]


I've been thinking along the same lines as you have. I don't tow (yet), but my '99 sits perfectly level unloaded. I'm sure that with a load, the rear would sag. Seeing as how you're getting a 3" sag with just a 150 lb. tongue weight, I'm not too optimistic.

I've thought about air bags, air shocks, and coil overs myself, but I haven't yet decided which way to go. Anyway, here are some thoughts about the choices:

Shackles: These will raise the rear a bit, but will not add any stiffness. If you carry a load often, these may not be the way to go. Also, keep in mind that an additional 2" of shackle will only yeild about 1" of lift.

Air shocks: These seem like a good idea, provided you don't go overboard with the pressure. The higher you pump them up, the more load you put on the shock mounts rather than the springs. Still, I think that the auto-leveling suspension used on some Explorers use air shocks. A good advantage is that they are adjustable.

Coil over shocks: These will also add stiffness, but like air shocks, will add load to the shock mounts. They aren't adjustable, but will reduce sag. I don't know how they would affect handling.

Air bags: These appear to be sturdy, and are adjustable. They won't put any additional load on the shock mounts, since they use their own mounts. I've thought about these, but my concern is if I go off road. I'm not sure how much articulation can occur. If a wheel goes too low, I'm afraid that the air bag could be damaged. I honestly don't know enough about them.

Add a leaf: Will add stiffness, as well as load carrying capacity (I wouldn't exceed the manufacturer's rating, though). They aren't adjustable, but they should be durable. I haven't been able to find out if they will fit my 3" (2 doors have 3" single leaf springs) leafs or not.

Helper springs: Should give an effect similar to add a leafs, but can be removed or re-positioned fairly easily (10 minutes). You can put them on when going on vacation and remove them or reposition them for less lift when you are unloaded.

Well, I probably didn't answer your question, and in fact, I probably raised more questions. Since I'm considering firming up the rear suspension as well, I thought I'd share what I am thinking so far.

BTW, if you go with a stiffer spring, you will probably want to change shocks as well. Something like the bilsteins or edelbrocks would probably work better with the harder springs. Remember that shocks really control the oscillations of the suspension more than anything. A stiffer spring will have stronger bounce to it, and will easily overcome the weak factory shocks.


PryBry: Just add air bags (aka: air springs) and change out the factory shocks with either KYB, Edelbrock, or Bilsteins and your problems will be over. I had the same frustrating problem and recently spent $600 out the door for Air Lift air bags and 4 KYB shocks, installed. The Air Lift rep "Chuck" was very generous with his time in taking my inquiry (800-248-0892) as was Edelbrock and KYB(my opinion: both shocks are equal quality and you will pay 50% less for the KYBs and you are good for 100,000 miles; any problem and KYB told me they would replace, no questions asked, under the lifetime warranty). Take the money you save and apply it towards the air bags. Problem solved! If you are in Orange County, California call Argo Enterprises at (714) 562-2701 and ask for Tony. He did my job and I have been very pleased with the quality and results. I was SO TIRED of sagging rear-end and the side-to-side rocking every time I went over a speed bump, etc. HUGE IMPROVEMENT with replacement of shocks for that problem, and the air bags took care of the rear-sag when I put gear into the cargo area, and/or used the cargo rack inserted into the hitch. The solution is simple, but info on it seems to be lacking and is not readily available to the public. Hope this help you!

Comment to Tom Wilks concern above about "articulation" regarding air bags: All the knowledgable people I spoke with in doing my research for the best solution to the problems we have with the soft suspension were unanimous in saying that articulation was not a problem in the off-road scenario; the various manufacturers have already figured that into the engineering and setup. I hope they are right, but it does appear to make sense that concern would be initially addressed by the engineers who design these solutions. After all, alot of them participate in off-road activities, and that is why they are working daily in the field. Must be nice to get paid for working during the week in an area of endeavor in which you recreationally participate on the weekends.

What is the weight of your boat and trailer combined? The reason I am asking is because most people have the wrong tongue weight set up on the trailer. Many boat dealers do not check the setup of the boat and trailer and most people take it for granted that it is correct. Then again, many owners start moving things around (bow stop location on the trailer) without realizing what they are doing. Generally, the tongue weight should be approximately 3-5% of the total combined boat/trailer weight for loads over 2000-2500 lbs. Any combined weight under 2000 lbs should be 5-7% tongue weight. In other words, at 150 lbs of tongue weight at 5%, your boat/trailer weight combined would be about 3000 lbs.

You would not believe how much difference this makes in the ride quality and safety factor by having the right amount of tongue weight. You can change your tongue weight by moving the boat forward or backward slightly on the trailer. Moving it forward will increase your tongue weight and moving backward will decrease it. Moving it as little as an inch one way or another can make a big difference in the tongue weight. If it needs to be adjusted, the easiest way to do it is to actually put the boat in the water, adjust your bow stop on the trailer and then put the boat back on the trailer and recheck the weight.


91 XLT 4x4


Just out of curiosity, do you know how many inches of travel the air springs have? Also, is there any info available that indicates how many pounds per inch of travel the airbags exert at a given psi (I'm looking for spring rate or the equivalent here)?

I'm leaning towards one of two paths here: Either a full length add-a-leaf with a recurve along with a torsion bar twist up front, or waiting to see how the ranger lift kit was adopted to the Explorer. At any rate, I've got a little time here, as winter's coming and I am not doing any mods until at least spring.


You bring back some not so fine memories of my old boating days. Dead Link Removed I used to tow the boad with a 1978 3/4 ton Dodge with a stick shift and manual steering. the beast was a beater, but the engine still had power (360 V-8). It did have a creeper (granny) gear, so pulling out of the ramps was not a problem, except for traction. Anyway, the trailer was not quite big enough for the boat, so a 4000 lb+ boat and trailer combo had a tongue weight of about 100 lbs with the bow stop all the way forward. Pretty bouncy. I went very slowly with it, as it was not quite safe. But, what can I say, I was young and in love, safety was far from my mind. Dead Link Removed


Hey all...I've been researching this topic for about 2-3 months now. I posted here a while back, but didn't get any response until recently (thanks to those who did!).

Anyway, just yesterday I broke down and ordered the Air Lift air springs for the rear & front(Explorer Express part #AX59506 for rear & #AX80777 for front). I didn't really need the front, but I'm calling it the poor-man's suspension lift. I also opted for the on-board air compressor system w/dual guages, for independent control of front and back.

I will be installing them next week, so I'll post and let everyone know how it works out.

I'm pulling a 21' travel trailer with weight distributing hitch. With the weight distributing system, it sags just a little more than I'd like, but the air bags should fix it right up.

'93 XLT 4x4
'93 Ranger Splash

RandyM, thanks for the advice.... I'm going to use the air springs and change the shocks. Do you know the part numbers for the air spring kits? and the shocks... does KYB shocks have a web site? or phone number... thanks again.

98 XLT V8