Project XK: 4″ Lift

[NOTE: As of May 2010, I have abandoned the 4″ BDS lift touted below and replaced it with a 4″ Superlift kit; my reasons for this change, and the results of it, are discussed in a separate and lengthy post.]

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Reasons for a Lift

Perhaps the most easily recognized modification — and certainly the most expensive — that most off-roaders perform on their rigs is the addition of a lift-kit.  The increased body height from a lift tends to improve the aesthetic appeal of a vehicle by giving it a more aggressive stance, but more importantly it indirectly provides for better clearance.

Why do I say indirectly?  Well, it’s a common mistake to equate lift with clearance.  I put a 4″ lift under my Commander, for instance, but that doesn’t mean I immediately had 4″ more clearance than I did pre-lift.  Not at all.  While it’s true that the geometry of the lift provides for some basic clearance increase over stock, what it really provides is enough space between the body and the axles (to simplify things) for you to fit bigger tires.  And real ground clearance is all about rubber.

In my case, the 4″ lift enabled me to replace my Nexen Roadian AT II tires, size 245/65R17, with a set of B.F. Goodrich All-Terrain T/A tires, size 285/70R17 (with 1.25″ wheel spacers to keep it all steady).  In more recognizable terms, that means I went from a tire with a diameter of 29.5″ to one with a diameter of 32.8″, an increase of 3.3″.  That’s diameter, of course: my actual ground clearance is a function of the radius (from axle to ground).  Thus my 4″ lift netted me about 1.65″ of ground clearance based on the rubber alone.

And a vastly superior look.  One doesn’t want to forget that!

Choosing BDS Suspension

When it comes to getting a 4″ lift for a Jeep Commander (XK), there are two primary options: Superlift and BDS Suspension.  Both kits, and their manufacturers, are solid.  Indeed, they share a number of parts.  Nevertheless, the most commonly used kit on these Jeeps by far is the Superlift.  It has been on the market longer, I believe, and it has also been consistently cheaper*; no surprise, then, that it has had the biggest market footprint.

Just because Superlift is more popular, however, does not make it better than BDS.  McDonald’s certainly has a far bigger market footprint than Good Times or Blake’s Lotaburger, a couple of small-chain burger joints out West, but I can assure you the food is superior at the smaller-share locations.  That’s not a knock against MickeyDs, by the way — I rather enjoy a stop at the golden arches now and then — but a testament to the quality, for instance, of a green chile cheeseburger at Blake’s.

At any rate, I went with the lesser-known BDS Suspension kit, and I’m glad I did.  The design and build of the kit is superior in almost every way; as I’ll discuss below, there’s one significant area where Superlift is superior (aside from the pocketbook, which can rightly trump everything else for many consumers!).

Installation

I’ve installed, or helped install, many lifts over the years.  I wasn’t about to do it with this one.  Regardless which 4″ kit one chooses, this is a job that will take a professional installer at least two working days.  It is essentially a full suspension replacement.  Aside from the basic manpower labor required to put such a thing together, the geometry of the XK means that cutting and welding is a necessary part of the installation procedure.

Shop around for a good price on your install, but also look for a good reputation and an installer who will stand behind its work.  And do be sure that a 500-mile retorquing is included in your price estimates.  You can likely be prepared to spend about $1000 when all is said and done on the install.

As it happens, I had my lift installed at High Country Performance 4×4 in Colorado, a very reputable installer.  Here’s a shot of my Commander in their shop, with the front partially completed:

Basic Results

Yes, yes, yes, you’re probably saying.  But was it worth it?

From a performance standpoint, absolutely.  The additional clearance is significant on the trails.  No question there.

From an aesthetic standpoint … well, you be the judge:

For my part, I think the lift was definitely worth it!

BDS vs. Superlift

I’ve had the opportunity to compare these two kits on vehicles that were literally side by side. I’ve seen them both on the trail, and I’ve banged about with tools on each.  I can tell you that they are both solid pieces of work.  That said, if I was choosing today, I’d still go with the BDS. Not because there’s anything wrong with Superlift (or McDonald’s), but because I have found the BDS to be better engineered and better built.

What you see here is the rear of my XK with the BDS installed. This is the closest I could get to a one-pic summary of what I really like about this kit vs. the Superlift. In a word, I’d say that the difference between the two is engineering. While they share a number of parts, the things they don’t share can be telling. If you look at the body attachment point for that upper control arm, for instance, you’ll see two things that make me very happy. First, a solid, durable bushing that is far superior to those you get with Superlift. These quality bushings are everywhere, which will really reduce squeaking over the long haul.  Even better, you can see a zirc fitting — which sure ought to be standard on suspension parts but most assuredly is not. These are “little” things, but they’re worth it over time, especially if your vehicle (like mine) is both a trail rig and a daily driver.  Advantage BDS.

In addition, you can see in the above picture the attachment point for the lower control arm, which is, well, pretty much stock.  Because it uses a different upper assembly, the BDS kit can maintain geometry by only adding 5 relocation brackets.  By comparison, the Superlift adds 9 — 44% more. There’s a double bonus effect here for BDS’s engineering: not only does each additional relocation bracket compound the likelihood of potential part failure, but Superlift’s lowering bracket on the rear in particular is a real magnet for rocks, hanging down in front of that rear tire and just begging to be smacked on stone.  The BDS thus should be inherently less prone to failure while simultaneously omitting Superlift’s dreaded clearance-reductions. Advantage BDS.

Next slide, please …

This picture is looking toward the front of the vehicle with the BDS installed (rag included for, um, scale). You can start to see here that the finish of the BDS parts is far superior to Superlift’s. The powdercoating is much thicker and much more “polished.” (Heck, I even like the color!)  If you care about aesthetic durability (which I do): Advantage BDS.

Back to the engineering side of things, though, that big beautiful grey crossmember matches one on the very front of the vehicle (which can be seen up on the right side). The “back of the front” crossmember in the foreground here is very different from the set-up that Superlift has, and it is (again) good engineering. By having such a significant rail-to-rail bracing, the BDS kit keeps the front end tighter and stronger than the Superlift does. At the same time, this crossmember helps to protect the mounting points for the lower control arms, which can take hits now and then in really rough terrain (which is not a good thing). All in all, it’s just more thought-out than Superlift’s set-up.  Advantage BDS.

Okay. So far it’s been mostly good for the BDS kit. But it ain’t all BDS roses. Now for the one real problem I’ve had with the BDS that the Superlift does not have…

What you see above is the front differential skidplate for the BDS. If you’ve ever seen the Superlift kit, you know that they have a much wider plate under the front end.  Advantage Superlift.

While I would like it if the BDS one was the same width as the Superlift one is, that’s actually not the biggest problem here: this BDS skid, after all, does cover the low-hanging fruit, and those heavy-duty crossmembers to either side of the diff area should prevent the majority (though not all) strikes into the axle area above.

No, my real problem here is that the BDS engineering, which is so great everywhere else, didn’t do so well here. As you can see, I’ve taken some blows on the skid. Big blows. I was, after all, field-testing the lift, and that means giving it a good hard workout: this damage was done pogosticking on the rockpiles going up to Red Cone in Colorado (trip pictures courtesy my awesome brother). Anyway, the point is that when it was really crashed down upon, the skid buckled back. Not enough to hurt the diff, thankfully, but enough to get an audible buzz off of it. It’s not the end of the world, but in my humble opinion this skid ought to be gusseted (and wider, and …), but it’s not.

Of course, I would be remiss if I didn’t bring up one small but rather significant point that’s apropos to this damage: BDS has a “no fine print” warranty. Seriously. That means that if I send this plate back to them — and I will do that pretty soon — I’ll get a new one. Doesn’t matter how the part failed, or why. It bent back and it shouldn’t have, so BDS will take care of it — that’s some real peace of mind for me.  Big advantage BDS.

Road-testing Results

So it looks good, and it did what it was supposed to do: give me room beneath the vehicle for off-roading.  But what did it do to on-road performance?

Well, I just got back from driving my stock XK from South Carolina to Colorado, where I installed the lift, swapped those 245s for 285s, put on all those mods, and then did a whole lot of ‘wheeling before driving the “new” Commander back across the country. Since I was field-testing the lift (and some other things, of course), I’ve been keeping very close track of things like my relative power and mileage.

First, the mileage…

Even with all the extra weight, the decreased aerodynamics (via stance and things like tossing the front lower airdam), the bigger tires, etc., I lost less than 1.0 mpg across the same stretches of road running at the same speed (via cruise control) using the same gas. There were factors I could not control, like the air temperature, but I did my best to keep things even. (And, as it happens, August temperatures were hotter than those on the way out in July, so any effect there would have made the lifted numbers look worse.) A lot depends on your driving, of course, but I think that little bit of effect on mileage is worth it for the positives of the lift.

Second, the power…

Driving in and out of the Rockies, I had plenty of chances to see how my changes effected power both on- and off-road. Happily, the changes were negligible in both cases. On the highway — say, going up I-70 out of Denver — I noticed that the tranny shifted down a bit sooner than it did pre-modding, but this was a matter of timing only: the Jeep never seemed to struggle or labor, and I only noted the difference because I was actively looking for it. On the trails, I didn’t see any significant changes post-lift at all — aside from all the rocks I was clearing!

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*Actually, the price difference is a little complex.  Here’s the manufacturer’s pricing:

• BDS: $1,994.73
• Superlift: $1915.92

Not a whole lot of separation there, especially with all the advantages the BDS kit has over the Superlift.  The real difference comes from the fact that Superlift, unlike BDS, has encouraged sales via distributors, including internet sales where significant discounts result. So even if the manufacturer’s pricing is similar, the consumer cost is not. At 4Wheel Drive Hardware, for instance, the Superlift is currently selling for $1606.99, which is nearly 20% cheaper than BDS. Those aren’t small potatoes, especially in this economy.