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Nuts & Bolts: What Would We Do?

Posted in How To: Suspension Brakes on February 13, 2017
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What Would We Do?

I have an old CJ that has been in the family 20 years and I set up nicely. I plan on retiring into a newer model JK in the near future, and I know it will sport an automatic, a hard top, and electric windows because the wife and I want more creature comforts. I’ll start with a stock one and already know it will be getting some form of upgraded traction control devices in the pumpkins as well as 4.88 gears, and people seem to be fitting 35- to 37-inch tires on them. This brings me to my questions. What would you do for suspension? There are so many choices! I plan on spending in the neighborhood of $3,000 including upgraded driveshafts. It must be 100 percent American made. There seems to be lot of people going with 3-inch lifts, but what’s wrong with a 4- to 4 1/2-inch lift since they’re about the same money? I’m thinking a short arm kit for simplicity with shocks and all the other doodads. It must be capable of handling highway speeds without death wobble yet flexible enough for those Rubicon-like situations. I plan on installing it myself. I’ve got an idea on a kit but am staying open minded to ideas. Maybe a mix-match of products that work well with each other? Any advice?

Steve R.
Via nuts@4wheeloffroad.com

We would probably update the CJ and use the rest of the money you would spend on a JK to take an awesome vacation somewhere, but it’s hard to deny that JKs are much more comfortable and capable that the old CJs. We understand giving in to things like heat that actually works, an engine that doesn’t need to be coaxed to life in the morning, and seats that don’t cause chiropractor visits after a day on the trail. JKS are also extremely popular, and if it can be bolted or welded on to a Jeep, someone makes it for a Wrangler.

As for the JK, for starters, we like your choice of 4.88s for 35s, but if you think you’ll be running 37s it’ll be best to step straight into 5.13 gears. That said, you are right to be concerned about the stock JK driveshafts, as they don’t do well long-term with increased operating angles than come with a lift. Several reputable driveshaft companies offer driveshaft conversions, and we would recommend doing both shafts if your budget allows, even though it’s going to eat up a good chunk of your budget. Though the stock stuff will live for a while with a lift kit, they just don’t last long-term. Swapping the Rezeppa-style shafts for more conventional shafts that use normal CV and U-joints is safe insurance against problems down the road. Check Tom Wood’s Custom Drive Shafts (4xshaft.com) for some of the best-made, longest-lasting driveline solutions out there.

The sky is pretty much the limit when it comes to suspension. Every major suspension manufacturer offers a full range of lift kits for the JK, which means there are several excellent lift kits to choose from. Rather than recommend a particular brand, we’ll spell out what we like to see in a lift kit and then let you decide which brand best fits the bill. There’s a lot of marketing hooey out there, so hopefully this will help you see through some of the jargon.

A quality lift kit is going to include new coil springs and shocks. Don’t place too much emphasis on “progressive rate” coil springs, because all coil springs have progressive rates regardless of the number of wraps per inch. Keyboard commandos will swear otherwise, but if there were an advantage to varying the number of wraps per inch on a coil spring in order to provide a more progressive rate, the factory would have done it that way (it didn’t). Because the JK suspension market is so competitive, most of the suspension companies have spent a bunch of time on spring rates and shock valving, so all of them are going to ride pretty well. We prefer a quality gas-charged monotube shock on the JK, but there are twin-tube hydraulic shocks out there that do the job. Most of the time a monotube shock is going to be an upgrade over the base kit, but not always. Remote-reservoir shocks are completely unnecessary unless you spend most of your time desert racing.

We would look for a kit that includes adjustable track bars front and rear rather than relocation brackets. Track bar brackets place more leverage on already marginal stock brackets, and adjustable track bars are also usually rebuildable. For control arms, we prefer adjustable arms that use OE-style rubber bushings. The adjustability allows you to fine-tune caster, driveline angles, and wheelbase, while the factory rubber bushings are going to be quieter and last longer than most aftermarket high-articulation joints. The added strength and marginal amount of suspension flex that articulation joints unlock is more than offset but the nearly constant servicing, tightening, and replacing of aftermarket joints. Unless you’re planning on a dedicated hardcore crawler, rubber bushings are just fine.

What does make a big difference in suspension flex and travel is a long-arm system. Though quite a bit more involved in terms of installation and expense, a long-arm kit offers very real off-road benefits, though those can come at the expense of on-road handling. A short-arm system, or one that uses the factory control arm mounts, retains most of the factory suspension geometry and is much easier to install, all while being significantly less expensive. If you’re planning on hitting some pretty hard trails and won’t be spending much time on the street, then a long-arm system is the way to go. However, if your four-wheeling is mild to moderate and you plan on spending a lot of time on the highway, then a short-arm kit might be a better choice.

Aside from these tips, we would recommend a kit that includes brake lines and sway bar links, while front-sway bar disconnects would be a big bonus. While many of these items can be added to a base kit if they’re not included, with the exception of shocks we are not big fans of mixing and matching components from different manufacturers. By sticking with a single manufacturer, you know that all of the components were engineered to work together and there’s less finger pointing if you run across a problem. Most of the reputable brands are going to be American-made, and most will mention this in their sales literature.

Lastly, in terms of lift height, JKs can easily clear 35s with a 3- to 3 1/2-inch lift, and 37s with minor trimming. Because that’s all the lift you need for your proposed tire size, we wouldn’t go any higher unless you don’t want to do any trimming. Though a taller kit might give you more ground clearance, it also makes entry and egress more difficult. Like working heat and rollup windows, that stuff gets more important as we get older.

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