The Jeep Geek

The Jeep Geek's Blog

The 4 1/2 Inch Lift

The Jeep Geek has been promising this article for quite a while and he hopes that the article meets with the enhanced expectations due to the delay. It has been a very busy time for The Jeep Geek as Jeep sales are up quite a bit over last summer and things certainly look like we have turned the corner economically here in the Front Range of Colorado. Not everyone who wants a job has one yet, but things seem to be getting better every month...or maybe we are learning to settle for less...The Jeep Geek doesn’t know which, but he has time this morning to write this.

The higher the lift, the more complex the engineering issues become. This is because the geometry of the suspension changes, and with larger tires, the forces on the drive line increase. These changes and increased forces have to be dealt with or damage to the drive line becomes more likely. In fact, some significant safety issues can be injected into a poorly designed lift.

So the first issue, short-arm or long-arm lift? The Jeep Geek recommends long-arm lifts if you are going to lift more than 2 inches.

Pasted Graphic 1

Short Arm show above. This lower arm is located here from the factory. If the suspension is lifted more than a couple of inches (say 2), the mounting point remains the same and the angle becomes more obtuse and is not able to withstand the forces that will be encountered off-road.

Now for the Long arm:

Pasted Graphic 2

Notice that the lower arm is much longer, in fact in this picture you can see the original mounting bracket and the long arm attached quite a distance beyond this. This geometry allows for a more robust connection to the frame and makes it possible to withstand greater forces on the wheel. From the two pictures, you can see that the material is also more solid for the long arm, further strengthening the suspension.

Another consideration in these more extreme lifts is drive shaft angle. It is not possible to re-use the factory drive shafts with this much lift as the angles will be greater than the 10 degree maximum for a universal joint. The replacement drive shafts used in the Mopar 4 1/2” lift kit are heavy duty and have double cardon joints. The heavy duty part is a result of the added drive line pressure from moving larger diameter tires. In fact up to 20% more force on the drive shaft from the larger tires. The double Cardon joints are composed of two U-joints which effectively doubles the amount of angular change.

For those who purchase a third party lift kit, buy the upgraded drive shafts otherwise you will be presented with a recovery event when your drive shaft breaks at the U-joint. With 20% more force on the factory drive shaft, coupled with a more severe angle than the U-joint is designed for, there will certainly be a failure...probably on a trail where AAA will be hard to contact.

So a word about shock absorbers. Most third party kits don’t include these...don’t skimp here. With the more extreme lifts like the 4 1/2” lift, making them perform on the highway safely becomes more difficult...especially tuning them with the Electronic Stability Program which rides on the ABS. It becomes harder to make all this work with cheap shocks whose characteristics are radically different from the OEM ones, and cheap shocks change their damping characteristics more quickly than better shocks. What this means is that cheap shocks that worked right after installation, don’t 5000 miles down the road.

In general The Jeep Geek likes the Mopar 4 1/2” lift kit because all of these issues have been addressed (together with half a dozen other issues that The Jeep Geek will discuss another day). While the cost of the Mopar Kit is higher than other third party kits, if you add the missing components to the third party kits, the cost is very close to the Mopar kit.

A couple of last minute considerations. Just like with the 2 inch lifts, The body pinch weld needs to be clipped near the rear tires. Also, the stock OEM bumpers will rub a 37” tire when they articulate up, so when installing the lift kit, it is time to replace that bumper.

Also, the stock OEM wheels will not work with the 4 1/2” lift kit. you will need wheels with a 4” positive offset to clear the frame members once the lift kit has been installed.

As long as you are doing all this, might as well put an off-road front bumper (with a winch) on your wrangler. All in, you are looking at about $15,000 to perform all the modifications assuming you use a shop to install these items.

Here’s the complete list of stuff:

  • 4 1/2” long Arm Lift Kit Including shocks, drive shafts, shimmy shock - $5700

  • 5 wheels and tires - $2500 (including the tire pressure monitors)

  • Rear off-road bumper - $750

  • Tire Carrier for rear bumper - $750

  • Front bumper and winch - $2500 (can be a little less, but budget for a good one)

  • Flat top off-road fenders - $1200 Gives a bit more room for full articulation

  • Labor to install all the stuff - $2500 (This will take a good technician 4 to 5 days to get it all done correctly)

All 2 inch lifts are not equal

So in the last post we discussed clearance issues to determine how much lift is needed. In this issue we will focus on 2 inch lifts and discuss the various considerations in picking a particular lift. The Jeep Geek will also explain why he feels that the Mopar 2 inch lift is ideal for most cases.

The Jeep Geek knows of lift kits that cost under $400 that include 4 2” spacers and four shock absorbers. The idea is to leave all the stock components in place (except for the shock absorbers) and place the spacers on the top of the coil spring to extend it’s size. These will give 2 inches of lift and permit the installation of larger tires, but there is a problem.

These kits are dangerous. They limit articulation so they are not good for off-road. (In fact they can articulate down and rip out the brake line...but cannot articulate up.) In addition they are not safe for on-road use as they change the suspension geometry and leave the vehicle subject to severe vibrations (sometimes called death wobble). If you cannot afford a correctly engineered and installed lift kit...wait...don’t install a cheap one or it will cost you much more in the long run.

So briefly lets look at a budget to do a lift. There is the cost of the lift kit, new tires, new wheels (yes the stock wheels will not work as you will need wheels that are offset to allow the larger (and wider) tires to clear the body, a rear bumper with tire carrier (you can’t mount the larger wheels and tires on the stock tire carrier). A reasonable budget will break down similar to:

$1600 for the lift kit
$3500 for 5 new wheels and tires (could be as low as $2500 for really cheap tires)
$1500 for rear off-road bumper with tire carrier
and about $1000 - $1500 for installation labor. Yup, there is a lot of work involved to get all this installed correctly.

So, how smart did it seem to put a $400 lift kit on in light of the other expenses. Bottom line is a $400 lift kit is unsafe at any speed.

At a minimum the lift kit you choose should include 4 heavy duty longer coil springs. 4 high quality shock absorbers, steering linkage to maintain steering geometry, anti-sway bar extenders, new bump stops to prevent over-articulation, an oversized steering stabilizer, and either new brake lines or a kit to move the brake line links to allow for articulation.

So why heavy duty coil springs? The Jeep Geek is glad you asked. You jeepers insist on bolting things like off-road bumpers, winches, gas cans, cargo baskets, etc to the bumpers. These add weight and have to be compensated for with heavy duty springs.

So lets assume that you have all these parts, are you good-to-go?
Not necessarily. Do the parts work together, are they engineered as a unit? Are they tuned for highway speeds, cornering, to work with the Electronic Stability Program of the Wrangler? If not, then there may be drivability issues. This is why The Jeep Geek likes the Mopar engineered solution. It was designed to work with these systems in the Wrangler.

As you can clearly see in the picture above, the lift includes a heavy duty steering stabilizer. Without this, any lift could be prone to high speed instability. A number of Jeep forums have documented this “Death Wobble”. In all the examples that The Jeep Geek has seen, this occurs on poorly lifted Wrangler JKs. If your lift doesn’t include an upgraded steering stabilizer you are asking for trouble down the road.

Now it is important to discuss some installation issues. First, the Mopar kit allows for full wheel articulation. This may require some modification to the body and fenders if 35” tires are mounted. The pinch welds of the body pans near the rear wheel will have to be trimmed slightly (just about an inch of the corner). If the factory rock rails are installed, they will also need to be trimmed slightly as well (to match the body trim).

Second, the rear fender may have to be replaced with a high clearance fender to allow 35” by 12” tires to fully articulate up. The Jeep Geek has seen some fender rubbing with the factory fenders. Mopar has released some flat fender flares that handle this issue nicely as well as provide a handsome and muscular appearance. These can be purchased for about $950 for all 4 fenders. The Jeep Geek will post some pictures of this shortly.

Now you are ready to do some serious rock crawling. Have fun out there.

Getting a Lift

You have seen them heading down the road...maybe you’ve seen them out on the trails...Jeeps with oversized tires. So how do they fit on a Wrangler? Simple, you add a lift to the Jeep to make room for the Tires. Other mods may be needed as well depending on tire size.

This article is the first in a series on lift kits and considerations that you should think about before lifting your Jeep. The Jeep Geek has helped many people find the perfect lift for their Jeep and will contribute his expertise here.

The Jeep Geek is often approached by customers who see a Jeep ,like the one in the picture above, that has been lifted with a 4 1/2” long arm lift. They tell him that they want one like that. The Jeep Geek then begins asking a number of questions and in the end saves them a lot of money and they end up with one that will serve their needs a lot better.

The Jeep Geek would like to comment at this point that he loves the Mopar 4 1/2” kit shown above...but this lift may not be the right solution for everyone. He has at least one customer who purchased this lift and had to modify their garage door to accommodate the added height of the vehicle. A little prior discussion may have yielded a more harmonious solution for the home.

So here’s how The Jeep Geek makes the determination as to the type of lift to recommend. First, are you going to off-road with this Jeep? Some folks buy the lift to put larger tires and just are interested in the appearance. Nothing wrong with this, its all about personal preference. In this case The Jeep Geek determines budget. A 4 1/2” lift kit costs about $7500 installed, the 2” Mopar lift kit is about $2500 installed.

If the answer is that the owner wants to lift it for off-road use, then The Jeep Geek wants to know where and what type of obstacle they intend to try to conquer. If their intention is extreme rock crawling, the Mopar 4 1/2” long arm lift kit will probably hold up better than a short arm 2” kit.

But the bottom line is what size tires does the driver want to put on. On the JK Wranglers the 2” lift kit will support 35” tires. The 4 1/2” lift kit will support 37” tires. Now we are just discussing clearance issues with the body and frame. Another consideration is the model Wrangler the customer owns (or is intent on purchasing). For example the Rubicon has Dana 44 differentials on both front and back axles. The Sahara and Sport have in Dana 44s on the rear axle but have Dana 30s on the front axle. The Dana 30 will support 35” tires, but the Dana 44s will support 37” tires. So if they don’t have a Rubicon, The Jeep Geek recommends a 2” lift.

The point of a lift is to improve off-road ground clearance. A 2” lift will provide 2 inches of clearance for the frame, but the Differentials will remain at the same ground clearance. The larger tires is what gives more ground clearance for the differentials. So if the Jeep has 32” tires standard and we add a 2” lift and put 35” tires on, the ground clearance at the differentials will have improved by 1.5” (half of the tire increase in size). However in this example the overall height of the vehicle will have increased by 3 1/2”...2 inches for the lift and 1.5” for the tires.

Now there is more to a lift than just size. In the next article The Jeep Geek will discuss some other considerations i
blogEntryToppern selecting the right lift for you.