Let’s talk tow vehicle rear suspension upgrades

Vehicle in question is a 2020 F-250 with the 6.2L gasser, 3313lb of payload capacity. I've been towing my ~6k lb enclosed race trailer, which barely stresses the truck at all. I'm now going to add a slide-in truck camper to the mix, which will put around 2k lbs of weight in the truck bed. Total weight is still well below the rated payload but mostly on the back of the truck, which causes a lot of squat and some tendency to sway with the higher center of gravity.   Rear suspension upgrades seem to fall into three categories:

- airbags that go between the frame and the rear axle (Airlift, Firestone)

- extended bump stops that go between the frame and rear axle (Timbren, Sumo)

- things that bring the auxilliary leaf springs into play earlier (Torklift upper/lower StableLoads, Supersprings)

Right now I'm leaning towards Timbrens due to their simplicity and lack of impact on unloaded ride quality, but was hoping to get some practical experience and recommendations from the hive. 

I have Airlift rear airbags on my 2021 F-250 with the powerstroke.  If you get the kind with the on-board compressor so that you can deflate them to the minimum, then they also have no impact on the ride quality when you're not pulling a trailer.  The other convenient thing about them is that you have push-button adjustability for the trailer nose height, which I find quite useful for getting it over the curb and into my side yard without scraping things.

I have not tried the other two options to compare them, though.

Thanks Codrus. I put airbags in a van I had and was 50/50 on them. Relatively complex install, many failure points (had to replace lines or bags a few times) and bouncy ride when loaded with the bags pumped up. I'm open to them if they're the best solution but interested in the alternatives. 

My E250 camper van has air shocks; when not towing I just lower the pressure. 

A couple of times I've forgotten to air them up and the sway is noticeable. 

Airbags are pretty magical other than the impact to unladen ride quality. But really, how often are you going to be removing the camper?

A coworker has an f350 that they use to tow a giant fifth wheel toy hauler. It has airbags and the leaf spring lockouts on it and it seems to work well.

I'll 3rd airbags. I used Firestones on my E150 towing a 20' enclosed and never had any issues with them. 

I've used Stableloads on my last two duallies with our Lance slide-in camper (4300lbs wet).  I didn't want the added complexity/failure points that come with airbags.  On my '04 I used the lower StableLoads, and fabricated my own uppers, on the '17 I'm just using the lowers, as I haven't felt the need to have both.  It takes less than 5 minutes under the truck to engage/disengage them, and zero maintenance other than a drop of oil now and then to make sure they pivot freely.  I do live in AZ, so they might need more regular cleaning/oiling in wetter climates or where there is significant winter/salted roads.  I also added a Helwig swaybar, but other than those two mods the suspension is stock and I've been very satisfied with the load carrying and handling.  I never mounted the camper before installing the StableLoads on the '17, but on the '04 they eliminated about 4" of rear squat.

I just put the AirLift 7500 on my '13 F250 to fix the squat. Went with the bigger bags over the 5000 so that they could be lower pressure but still handle the weight. With only 20psi in them the squat is gone and unloaded the ride is only a little rougher but still way smoother than my 04 F250 was. But the 04 didn't squat either, so there was obviously a spring change to increase ride comfort at some point.

A rear sway bar would be a good upgrade too if your truck didn't come with one. Especially with the high weight center of an in box camper I would expect.

I had Sumo Springs on my 2017 Colorado to help with the Uhaul trailer + Elantra. Think 5000-5500lbs car and trailer total. 

Loaded it felt fantastic. Unloaded was not fun.

I would go Firestone airbags with an external pump. A small battery powered air pump from many of the tool manufacturers are cheap and easy to use. Put the chuck somewhere accessible(rear bumper or wheel well). Pump up before you load up and deflate once you are done.

I went with new leaf springs, 1000 pounds higher capacity than stock.  I know it doesn't mean I have more capacity but it gave me much less sway and bounce when loaded which is when it matters. Don't care about a rougher ride when empty it is a truck and it now works better as a truck when doing truck things.

I had airbags on my last truck and would go with something like the torklift stableload if I had to do it over again. Airbags do a great job of reducing squat in the rear and I like the infinite adjustability. I didn't like the amount of sway the truck had with the airbags and the high center of gravity of the camper. From my research, the forklift stableload or similar do a much better job at reducing sway especially with truck bed campers. If it's only tongue weight or squat you need to eliminate I'd say any of the options would work well. 

WillG80 said:

I had airbags on my last truck and would go with something like the torklift stableload if I had to do it over again. Airbags do a great job of reducing squat in the rear and I like the infinite adjustability. I didn't like the amount of sway the truck had with the airbags and the high center of gravity of the camper. From my research, the forklift stableload or similar do a much better job at reducing sway especially with truck bed campers. If it's only tongue weight or squat you need to eliminate I'd say any of the options would work well. 

That was another complaint I had with the Airlift system in my van, it seemed to actually make the sway worse. When the bags are tied together with the same air lines the work the opposite of an anti-sway bar; when the outside wheel gets loaded, the air rushes over to the bag on the inside wheel and jacks it up higher. 

Rodan said:

I've used Stableloads on my last two duallies with our Lance slide-in camper (4300lbs wet).  I didn't want the added complexity/failure points that come with airbags.  On my '04 I used the lower StableLoads, and fabricated my own uppers, on the '17 I'm just using the lowers, as I haven't felt the need to have both.  It takes less than 5 minutes under the truck to engage/disengage them, and zero maintenance other than a drop of oil now and then to make sure they pivot freely.  I do live in AZ, so they might need more regular cleaning/oiling in wetter climates or where there is significant winter/salted roads.  I also added a Helwig swaybar, but other than those two mods the suspension is stock and I've been very satisfied with the load carrying and handling.  I never mounted the camper before installing the StableLoads on the '17, but on the '04 they eliminated about 4" of rear squat.

 

If you were to go with only the upper or lower StableLoads, which would you choose?  Seems like the lower ones have a more dramatic effect?

In reply to ShinnyGroove (Forum Supporter) :

I would start with the lower StableLoads.  At least on the Dodge, the upper ones have to be removed, they don't swivel in/out like the lowers.  Not sure about the Ford.

I have the firestones and would definitely go that way again. I have 2 separate scraper valves so I don't get the side to side flow others have referenced. It takes a little longer to get set up but sounds a lot safer. The only issue I have had was a line that came loose from my poorly executed instal that touched an exhaust line and melted a hole. Easy fix and no other issues since.

I have found that stiffer shocks go a long way as well. Many well-damped vehicles get really wallowy/a bit unstable with a lot of weight on the back. Obviously adjustable shocks help a lot here, and they can make a vehicle that has some squat to it still handle just fine and then you just pull some clicks out when unloaded. Unfortunately few aftermarket options have compression adjustment, but that seems to be more effective at controlling the wallow motion vs. adjustable rebound (with some crosstalk) that many shocks have. Accutune off road valved some Fox shocks with the LSC adjustment for my suburban 2500 and they made a dramatic difference vs. the bimodal Autoride stock "active" shocks.

ShinnyGroove (Forum Supporter) said:

- airbags that go between the frame and the rear axle (Airlift, Firestone)

- extended bump stops that go between the frame and rear axle (Timbren, Sumo)

- things that bring the auxilliary leaf springs into play earlier (Torklift upper/lower StableLoads, Supersprings)

The airbags that go between the frame and springs are pretty baller.  I strongly suggest some kind of on-board air - not only for filling on the fly, but also because many airbags need to have a minimum pressure or they can become damaged.  Keep 15-20 psi and you'll never notice it unloaded.  Pump them up for hauling and they help a ton.

The extended bumpstops and helper springs have some limitations.  They're fine, but they require either A) a certain amount of squat before they engage, or B) need to be adjusted so they help right away, at which point they affect ride quality.

As an add, don't forget the tires. A 10-12 ply tire will go a long way toward stabilizing a load when it comes to swaying. Especially true on a SRW truck. 

I ran my airbags at 60 psi and the 10 ply rear tires at 80 psi. It made for a very stable load. 

Drop the trailer, lower the airbag pressure to 15 psi and the tires to 45 psi and it drove and rode like a normal passenger van. 

The 2019 F150 I bought used has a airlift system on it. Pretty slick, I can adjust the pressure left or right with an app on my phone. Min pressure is 5psi, I can go up to 100 psi.

I don't need it, my trailer is way to light to need it.

Also - those who complain about the reliability of air bags, semi trucks use them, they are not unreliable. Just dont buy cheap and install them correctly. 

My Firestone system had 80k miles on it by the time I sold the van. I didn't have any issues. 

Curtis73 (Forum Supporter) said:

The extended bumpstops and helper springs have some limitations.  They're fine, but they require either A) a certain amount of squat before they engage, or B) need to be adjusted so they help right away, at which point they affect ride quality.

This is where the lower StableLoads are really slick.  They mount to the lower override, and pivot in/out to engage the override spring at normal ride height.  Takes just a few minutes to switch them over when you're getting ready to load up.  It actually takes longer to adjust the tire pressures in the duals.

It seems like the lower Stableloads shown by Rodan are a nice compromise, and fairly simple to install and reliable.

I went down the rabbit hole last night of researching airbags and I'm pretty sure I don't want to go down that road again.  The Firestone system with the onboard compressor is almost $1300 in total.  While the install isn't the worst thing in the world, there are a lot of failure points.  When I read the reviews, there are a lot of complaints about the kloogy phone app not connecting properly to the compressor.  And the compressor forces you to do a single-line install which pairs the airbags together and causes the sway issues I experienced in my van.  If I do the airbags I'll probably just run separate lines and put the Schrader valves on my back bumper  instead of installing the onboard compressor.  It's pretty easy to carry a battery powered compressor around in the truck.

In reply to ShinnyGroove (Forum Supporter) :

That is what I did to mine. Separate lines with Schrader valves. When I set the tire pressure for towing I also filled the bags. Simple and trouble-free. 

ShinnyGroove (Forum Supporter) said:

When I read the reviews, there are a lot of complaints about the kloogy phone app not connecting properly to the compressor.  And the compressor forces you to do a single-line install which pairs the airbags together and causes the sway issues I experienced in my van.  If I do the airbags I'll probably just run separate lines and put the Schrader valves on my back bumper  instead of installing the onboard compressor.  It's pretty easy to carry a battery powered compressor around in the truck.

FWIW, the airlift system that I have includes a dedicated remote as well as offering a phone app.  I haven't bothered with the phone app, I just keep the remote in the center console and I haven't had issues with wireless connections.

Yes it's more expensive.  IME it's worth it, because otherwise I always forget to set the pressures until I'm on the road and then I don't want to stop (I had the bumper system on my previous truck)

I haven't had the sway issue, but I'm just towing a trailer with a lot of tongue weight, not hauling a camper.

A simple but effective method is to just use a 12v compressor hooked to a manual regulator like you would find on a shop air compressor.  That's how many of our B-buses (cutaway van buses) were controlled for weight on the tag axle.  People get on, turn the knob, drive.

Mount it somewhere outside, otherwise you'll get hisses every time you go over a bump.  Just turn the knob until the gauge reads the pressure you want and roll down the road.   Cheap, and very effective.  I see no need for a phone app.  If you want isolated bags, just plumb in two regulators, but in all honesty linking them isn't an issue for towing or load handling or sway.  Isolating bags is for handling applications where you don't want air transfer during cornering.