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We are looking for a little help for our F-150 rear suspension.
We traveled from Mesa, AZ to Topeka KS, it’s a little low in the back with a slight stability problem. What would be the best way to address this problem; add a leaf spring, install air shocks or install air bags? Here are our specs:
2013 F-150, 4x2, SuperCrew Short Box, EcoBoost 3.5L V6, Electronic 6-spd Auto, 3.31 w/electronic locking rear axle and Heavy Duty Trailer Towing.
Gross Trailer Weight (GTW) 9400 lbs.
First thing you need to do is weigh it. From what you posted, sounds like it's overweight. Once you have actual real weights, then we can go from there to determine what can be done to alleviate the stability. Slapping springs or bags on and calling it a day is not the correct way to go.
I agree that your truck is probably overloaded. The cure for that is a lighter trailer or a higher load capacity truck. It could be that the trailer doesn't have enough of it's weight on the tongue. It should have 10-15% of the trailer weight on the tongue. The cure for that is to redistribute the load inside the trailer. It could be that the weight distribution hitch is not properly adjusted. The cure for that is to adjust the hitch head to the proper tilt and put the proper amount of tension on the spring bars to transfer the proper amount of weight to the front axle.
Go to the scales. Find some scales here: http://www.publicscaleslocator.com Weigh it three times loaded for camping with a full tank of fuel and all the passengers in the truck. Weigh it once hooked up for towing, once with the weight distribution bars disconnected and once with the truck only. Remove the hitch when you weigh the truck only. Then you can determine if the weight distribution hitch is properly adjusted and if the truck is overloaded. Bring the weights back here for some suggestions. Also check your payload sticker on the edge of the driver's door and the weight sticker underneath the hitch receiver.
Last edited by atwowheelguy; 05-17-2017 at 03:48 PM.
Adding suspension upgrades won't solve the main issue, and that is an overloaded vehicle.
If after everything is said and done, hitch properly setup, weight properly distributed, and under the Payload/GVWR of the tow vehicle, then adding these items to smooth the ride is OK.
To add them to make up for the inadequacies of an overloaded tow vehicle is not only illegal, but dangerous.
Without actual scale readings on the OP's rig, it is only speculation at this point, but has the indication that the trailer may be too heavy for his truck.
Based on this, and confirmed by the 2013 RV and Trailer Towing Guide, your tow rating is 9,400. That is not the actual GTW, but the max GTW you can have without exceeding the GCWR of your F-150 when the F-150 is hauling nothing but a skinny driver. But the GCWR (and tow rating) is not your limiter as to max trailer weight you can tow. Your limiter is probably the payload capacity of your F-150 that is available for hitch weight, or it may be the weight limits of your receiver hitch.
With your trailer's GVWR of 8,200 pounds, you probably have it loaded to around 7,500 pounds when wet and loaded on the road. 7,500 GTW is about 975 pounds tongue weight, or 1,075 hitch weight with a good WD hitch.
My similar F-150 is overloaded with my TT that weighs less than 5,000 pounds with 650 pounds hitch weight. So I'll bet your F-150 is severely overloaded with over 1,000 pounds hitch weight. The only way to know for sure is to weigh the rig on a CAT scale while on the road for an RV trip. Add the weights on your front and rear axle and compare to the GVWR of your F-150.
If you're overloaded, and you don't want to trade for more truck or less trailer, then you cannot fix the overloaded condition. You can mask the overloaded condition by installing air bags in the rear suspension. Pump up the air bags to eliminate the sag in the rear suspension when the trailer is tied on with the spring bars tight. Your rig will then look okay so as not to attract the unwanted attention of Smokey Bear, but you must realize that you're still overloaded and drive accordingly.
1] A separate Schrader valve for each air bag = less convenient to adjust the PSI.
2] Both rear air bags tied together with one Schrader valve to air up both bags at once. A bit more convenient than 1], but still a PITA.
3] Both rear air bags tied together, but with an air compressor and controls to adjust the PSI from a dash controllor. Most convenient, but a lot more expensive than the manual systems 1] and 2]. About $275 to $600 over the price of just the air bags. Here's the best from Firestone: https://www.etrailer.com/Vehicle-Sus...one/F2168.html
05-17-2017, 10:48 AM
Rear Suspension for TT towing
