Rear Suspension Upgrades

Hey y'all. Been reading up on all the possibilities for rear suspension upgrades. The internet is quite divided as usual.

Just like all stock 1st gens my truck is bottoming out with a small load in the back. I need to upgrade the suspension. I will be hauling a cargo trailer with all my tools and belongings across the country in about a month. I do not plan to exceed the GVWR but I will be close. I plan to consistently haul the tool trailer after the move.

Initially I was planning on getting an AAL and new shocks but I have heard that this will not be enough. I then moved towards getting new HD leaf packs, the cheaper ones since I am on a budget. Upon more research I discovered that many Tundra owners just installed some air bags. This morning I discovered RAS.

At first glance RAS seemed like the way to go. Affordable, easy to install, and improves handling. Then I realized I probably still need new shocks. RAS is only ~ $200 cheaper than new shocks and HD leaf packs.

Should I get RAS and make the trip then upgrade the shocks? Should I scrap the RAS idea and get the leaf packs and shocks?

Are airbags even an option here?

Thanks for the help in advance

 

Airbags sound like a great option for you

 

My experience, for what it's worth. Blown leaf springs are blow leaf springs. They shouldn't bottom out with a small load (though we'd need to define "small"). You'd get by with airbags for this trip, but you'll eventually need new leaf springs (and shocks), HD or not.

Airbags are great if you're going to be hauling heavy loads regularly. But using them to try to mask blown springs isn't the best approach. I've tried it. Air is a harsh ride.

"Problem" with the HD springs is the ~1 1/2" lift they give you. Now you need to lift the front, too, unless you want to be really slanted. If you haul enough, it's a necessary evil. I'm likely going to do it this spring. But it's another consideration. Your back end will be really high.

Sumo Springs would also get you through. But for the price, airbags are probably a better option. My Tundra has the original leaf springs and Sumo Springs. With a ~900 pound camper in the bed, my truck sat level. Not squatted. Rough ride, because it was fully compressing the Sumo Springs, but it kept me from squatting.

With a ~150 pound topper and loaded with camping gear - plywood sleeping platform, heavy cooler, water etc. - my original leaf springs still keep the truck from touching the Sumo Springs. That much weight (maybe 250 pounds?) didn't compress the leaf springs much. Depending on how your truck was used, your springs might be more worn out. When I bought my Tacoma, it hit the bump stops every time I drove over any kind of dip in the road.

 

In this case a small load is my empty 15’ cargo trailer or a couple hundred pounds of tools in the bed. When I say bottoming out I mean on speed bumps.

My leafs are also slightly out of alignment. Meaning they are not stacked perfectly on top of one another.

I suppose if I got air bags I could still use them with new leaf packs in the future. Or sell them.

 

The Firestone bag kit is the way to go for your case, at least if you have no intent to lift, just make sure you plumb the bags independent of one another else it defeats some of the purpose of having them, you’ll introduce roll if the airbags are able to pass air back and forth between each other.

But you may also consider doing the non-HD springs from ATS also, if your factory pack is worn. This will help firm up the back end and help avoid axle wrap while towing, which is a legit concern.

Lastly, the general lifespan of struts and shocks is considered to be 100k-ish miles, plus or minus 25k depending what you’re buying, price point, and purpose. When is the last time you replaced yours? If you’re staying stock height, no lift, Bilstein 4600 is a good option, then reuse your OEM springs/tophats.

 

Are you saying that the lift from the HD packs will make axel wrap more likely? I assumed getting HD packs would be better for towing but I don’t really know. My truck has 315k miles. I have no idea when or if the springs were replaced. It was in really good shape when I got it in 2019. Until recently I have rarely towed or hauled much.

I am just now discovering that the leaf fanning I have needs to be addressed immediately.

I do have plans to get some Bilsteins. Maybe my initial plan to replace the packs and shocks is the right move?

 

I am saying axle wrap naturally will happen on 300k-mile old leaf packs, especially if you lift with blocks - not that you will, but just saying - old leaf packs are prone to twisting/torsion, and that impacts your pinion angle when gassing it, and when towing, or worse when doing both.

Replacing with new, stiffer leaf packs will mitigate wrap. Add in airbags, and you are ready to go with towing, you can adjust support in the rear before you tow or haul to shore/firm up the rear, and should be good for another 200k-300k miles over your next couple sets of rear shocks.

I would not buy HD leaf packs unless you want or intend to lift your truck. You will get no less than 1” lift out of those. Probably more, if my truck is an example.

 

Empty trailer shouldn't have the truck resting on the bump stops. So either way, time for new leaf springs. Like `shifty said, airbags are a great option, and even if you replace the leaf springs, they'll still come in handy if you tow/haul fairly often. Not a bad investment. If you got airbags now, then leaf springs later, you could experiment with heavy loads and the airbags aired down as low as they'll go, and decide if you could do without them.

When I had my Tacoma, like I said the leaf springs were completely shot. But I got by for 3-4 years with installing airbags. I towed a 17' camper trailer, plus tools and a lot of other stuff in the back of my truck, under a fiberglass topper, often with a 70lb canoe on top.

It doesn't take much to kill these OEM leaf springs. Sag after years of using topper and occasional loads is one thing. But it seems like just a short period of using them like a full-size truck, and they really are blown. I bought the Tacoma off a friend. For maybe 2 months he was using it to haul waste to the landfill from his house renovation. Wood, concrete etc. That's all it took so that any bump in the road would have me hitting the bumpstops.

With my Tundra, the leaf springs seemed to be in pretty decent shape. I still had the OEM rake, and they felt good. But after about 4 weeks with the 900lb camper in there, even with Sumo Springs, I feel like my truck is level now, and the back end feels a lot softer. The leaf springs in these trucks hold up fine for recreational use. But put them to work, and they're toast pretty fast.

But the HD packs will absolutely give a very noticeable lift. My Tacoma looked pretty silly for a while. Ended up getting lift coils in the front to level it out. Really didn't want a lift, but felt that to get the rear suspension I needed, a lift was unavoidable. Still going back & forth with the Tundra...HD leaf packs and keep the Sumo Springs? Then put at least OME 2883's up front, if not 2884's to keep it from being way too ass-high? Or go with non-HD leafs, airbags, and keep the front stock? I don't know yet...

 

I very recently installed firestone airbags in my 2004 AC. I still have the stock supple leaf springs. The leaves were fanning out a bit so during the bag install it gave me a reason to loosen up the U bolts and whack the springs back into alignment.

 

Fresh leafs means fresh bushings. & fresh bushings are always nice.

 

I'm running the stock leafs with Hellwig 990 helpers and Timbren bump stops on my '06 AC for towing/hauling. It's working well as I didn't want to lift it at all. But I do wish there was an HD replacement spring with zero lift available.

 

Totally. 2nd gen Tundra HD springs (all the usual suspects - ATS, General etc) don't give any lift, apparently. Not sure why they can't do the same for 1st gen. The HD springs are a great cheap solution for people looking for a lift, but for those of us looking for an HD suspension without the lift, there aren't many choices.