New springs or air bags to fix towing sag

[Rogue-Runner]

Hey all, I've got a 2017 SR5 w/ TRD Pro Bilstein struts and shocks + a 2/1.5 CF spacer. The truck is pretty well leveled out unloaded. There might be 1/4 reverse rake, which bugs me but not enough to do anything about it. However, when I tow some PWCs twice a month, the sag is so bad that it looks like my 4R trying to take flight.

I'm not going to install a thicker rear spacer, so I think my options are new rear coils (2"?) or air bags? The thing is I really like the ride quality right now, and I want to avoid stiffening it up. Also, I'm worried that if I buy 2" coils, it'll end up raising the rear more than just .5" if in fact my current OEM coils are saggy. It only has 42k miles, so I don't know if my coils are bad or the spacers are what's making it look funky when I tow. What's the best way to add .5" or so rear lift, prevent excessive sag when I tow, and keep the ride quality more or less unchanged. That's a hard ask, and I know I'm up against physics here, but the creativity on here never disappoints. Thanks for the feedback!

 

[Bill Z]

Look at the trailer rather than the truck...

How is the tongue weight on your trailer? With a well balanced single axial PWC rig you should be able to easily pick up the tongue and place it on the hitch. If not you have a trailer issue, not a suspension problem.

I tow a 2200lb boat/trailer loaded down with an extra 500 lbs of gear on a stock 4Runner. As long as the trailer is balanced I have no issues with sag etc.

 

[Smitty19TRD]

The tongue should only have 10-15% of the trailer's total weight. As was said check the trailer first. After that, look at suspension.
I have the factory rake, the truck is level when I hook up my boat. It's part of the design. Without a load leveling system you will have some sag with a load, or springs so stiff your kidneys will bleed when not loaded.
Airbags are a load leveling/helping system and is what I'm looking into for my truck. Based on your post, this sounds like your best bet if trailer adjustment doesn't get you what you need.

 

[Cymon]

If you like the current ride go air bags. 1/2 the price of new springs, easy install and they're easily adjustable. We've had ours on for about 1.5 years now and it has completely changed our towing experience...and I still have the OEM suspension with 85k+ on it.

 

[davem]

Been running Airlift bags for over 3 years now. They work great. No load keep 5 psI in them. When pulling my bike trailer with my Harley in I put about 25 psI in them and Runner has no squat.

 

[Smitty19TRD]

Cymon and davem,
Do you guys mind sharing the airbags you are using? I've been looking at a few but have never used them so I don't have a reference.

 

[keyser_soze]

I was in a similar situation as you. I tow a small travel trailer (1700lbs) for camping. It didnt sag that much but it was noticeable. I decided to use this as an excuse to upgrade everything (springs, UCAs, bump stops, bushings, airbags).

Long story short the airbags are great. They are cheap and easy to install. They remove the sag caused by my trailer, which makes the handling much better with the trailer, without making the ride harsh. Very easy to inflate or deflate. Without the trailer and the bags deflated you will retain your OEM ride.

Airlift 1000 60809 This is the cheapest I found them shipped. use the code "buynow" for 5% off.

 

[Jetboy]

FWIW -I've used both airlift and firestone bags in my 4Runner. I prefer the firestone. The airlift are a fatter air bladder so even fully deflated they still give a lot of resistance to the springs and make the ride rough. The firestone narrower air spring doesn't cause the same issue deflated. So I'd spend the extra $10 or so for the firestone ones. Otherwise they're very similar in function.

 

[davem]

Cymon and davem,
Do you guys mind sharing the airbags you are using? I've been looking at a few but have never used them so I don't have a reference.

Airlift air bags.


Sent from my iPhone using Tapatalk

 

[AdventureMan]

Based on the amount of sag I was getting with a 400-500 lb tongue load (my springs are all stock), I knew I needed some kind of load helper when towing. I was looking for an alternative to air bags because I also use my 4Runner off road and wasn't completely comfortable with cutting out the secondary rubber springs/cones inside the rear coil springs (to be able to use air bags). So I decided to try a "solid state" approach by using Timbren bump stops in the rear, but picked the softer "Active Off-Road" version as some reviewers felt the SES Bump Stops were too harsh.

These are basically rubber helper springs that bolt in place of the outboard frame bump stops. They don't engage when the rear is unloaded, but start to come into play when the rear is loaded down more than an inch (YMMV, depending upon your lift). I've used this setup to tow a 3800 lb. track car and trailer rig, and it works great. They are also not nearly as progressive as air bags, which for off-roading is a good thing. They might be a bit more expensive than air bags, but are a lot easier to install (no air lines to worry about)...

 

[jgatliff]

I’d go with airbags. I had a set installed in my 2018 and it made a world of difference towing our Teton X hybrid.

 

[Sky]

I have airbags on my F350, my FJCuiser, my Transit and my 4Runner.
I wouldn't go any other way- the quick and easy adjustability is priceless.