It's not uncommon to be asked the question:
I'm about to upgrade my rear suspension. Should I get an AAL (add-a-leaf) or a whole new (possibly custom) leaf pack?
Since there's never an easy answer, here's what I'd say... it depends.
Actually, there are two easy answers:
- If your existing leaf pack is in reasonable shape and you're not regularly hauling heavy loads (several hundred pounds) in the back of your truck, go with the AAL. It'll give you a lifted look, will work fine for the occasional load, and will be the most economical option.
- If your existing (probably stock/original) leaf pack is not in good shape (it looks completely flat with no load, or even like a frown), then skip the AAL and get a new leaf pack - either a new OEM pack, or a slightly more expensive (but higher quality) aftermarket pack.
If you don't easily fall into one of the categories above, then here's how I'd approach the decision making process...
First, remember, there are trade-offs
Whenever you update your suspension - front or rear - you need to remember that each option has pros and cons. If you are going to raise the rear of your truck, you're going to be changing the geometry of (primarily) the drive shaft, which can be hard on your drive line. You'll also be changing the weight distribution (and therefore braking characteristics) of the truck - another thing to keep in mind.
Additionally, some options will allow you to adjust the amount of lift - so you can minimize these types of changes, or at least "adapt" to the circumstances. Others won't. But, as is often the case, being able to "adapt" often means that it won't be as good as a dedicated solution for some set of circumstances either.
OK, so what are the options:
- pros: cost, lifted look, a bit more carrying capacity
- cons: no adjustability (change the drive-line and braking geometry), not (usually) long lasting, not a ton of carrying capacity,
- pros: cost, easy install, more carrying capacity, lift/capacity-adjustability (doesn't have to change the drive-line and braking geometry), lifted look
- cons: often leak (slowly, over several days), limited additional capacity, aren't usually the best-of-breed "shock absorber"
Custom Leaf Pack
- pros: more (constant) carrying capacity, long(er) lasting, lifted look, allows use of best-of-breed shock absorber
- cons: harder adjustability (changes the drive-line and braking geometry; adjustable by adding/removing leafs), cost
And here's my recommendation:
If you rarely carry loads, you're a good candidate for an AAL or air shocks, and I'd give the slight advantage to air shocks. Both will give you a lifted look, but air shocks have that adaptability - you can lower them (closer to stock levels) if you want to relieve the stress on your drive line. If you go the AAL route, make sure to look into a brake proportioning valve as well, since you'll have changed braking characteristics.
If you regularly - but not constantly - carry loads, then you need some way to keep from overloading your leaf springs. In that case, you should consider either air shocks or a heavy duty leaf pack (possibly custom). For years, as long as my truck didn't have a constant load in the back (loads were for remodeling supplies, landscaping, or dump runs) I went the air shock route, first installing Gabriel HiJackers and then Monroe MA-820's. They worked great and were significantly less expensive than a custom leaf pack. They also had the benefit of adaptability - when I wasn't carrying a big load, I could leave the truck in the "stock geometry."
If you constantly carry heavy loads (several hundred pounds) then you are a good candidate for an after-market leaf pack. Neither an AAL nor air shocks are up to a "constant" load. The AAL will relatively quickly go flat, and air shocks have a weight limit as well as (generally) need to be refilled over time as air slowly leaks out - inconvenient if you always have a load.
You may decide to go with an off-the-shelf option, like OME or you might decide to go the custom (for additional cost) route - Alcan or Deaver for instance. Base this decision on the load characteristics of your situation (how heavy is your constant load) as well as budget. Personally, as my truck has become more AdventureTaco and less "remodel Taco," I've got a load back there all the time (tent, gear, etc.), so I chose to go with a custom Alcan pack since there was no way to get a 600lb-over-stock pack from one of the off-the-shelf vendors.
Given the constant load back there they've been great, but I wouldn't want to run them with no load - the back would be way too high (and it'd create a bad angle for the drive line). Of course, you can adjust that by removing leafs, but that's nowhere near as convenient as adding air to some air shocks. Note that I did have to install a brake proportioning valve as well, since the constant lift changed the braking characteristics.