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Choosing A Lift For Your Jeep

Category:  Technical

Choosing A Lift for Your Jeep

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Not sure which lift and tire size are right for your Jeep? This article is for you.

Just like choosing wheels and tires, the decision to lift a Jeep is not a light decision. The wrong lift can dramatically affect the way a Jeep handles. Because everyone is different, first consider this one important question:

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What do you want to do in your Jeep? 

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2.5" Lift
Will it be a commuting vehicle, spending a lot of time on the freeway? Or will the weekends occupy its primary usage? Or, will it be a dual-purpose vehicle, driving both off-road and on-road? Over half of new Jeep owners are most likely in the dual-purpose crowd, and a small lift would do the trick. This allows a weekly commute, while on the weekend we can go air down the tires, lock it in, and take the kids fishing.

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At TeraFlex there is a butt for every seat, tire size, and lift.

Former TeraFlex Vice President Jeff Mock says:

“Most people think the higher they go, the better the lift. That they need higher ground clearance to clear bigger tires and four-wheel better. I’ve always thought the opposite. The lower you go, the lower you stay, and the more stable your Jeep. I usually get [33” tires with] a 2.5-3” lift.”

.4" Lift 

Joe Thompson, of TeraFlex International Sales, however, loves to go big:

“In the past, I liked the 3” kits with a 35” tire combination. But after I saw a JK that TeraFlex built with a 4” kit and 37s, I knew that's what I wanted.” 

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Love at first sight.

AJ Swenson, formerly of TeraFlex National Sales, goes even bigger:

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“I think I will always have 40” tires. Clearing that 40” is going to take a 6” lift. I did our 6" Elite LCG Long Arm Kit.”

6" Lift

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Basically, the tire size and lift kit go hand-in-hand. First, choose which tire to run, and then base the lift height off that tire size. Most Jeepers probably aren’t driving 10 out of every 1,000 miles on the trail, and will want a Jeep they can drive around town. Something that can run those daily errands or go on vacation with; that’s stable on the road and can still go to Moab for a good time off-road. For many, these Jeeps are a second vehicle and for some a primary one. For those with families constantly climbing in and out, which is becoming more common, a lift height that maintains ease of access is often ideal.

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2.5" Lifts

Bryce Calvin, TeraFlex engineering supervisor, says:

.2.5" Performance Spacer Lift Kit

“The big advantage of the JK/JKU 2.5” Performance Spacer Lift Kit is that you’re able to get a larger tire without the expense. Because the Performance Spacer Lift Kit is just a spring spacer, you still use your factory springs. Luckily with a JK[U], we have bigger openings. Meaning that with a 2.5” Performance Kit, we’re able to run up to a 35” tire. But, it all depends on what type of trail you like to run. 

“If you start running slightly harder trails, you’re going to have a hard time with some obstacles. You’ll have less ground clearance, less break over angle, less approach angle and departure angle. You want to be sure you’re tall enough for clearance. Otherwise, you’ll drag. 

“Although, it does depend, because maybe you’ve got heavy-duty rockers and skid plates. And yes that will keep you from getting body damage. But you can still get hung up.”

.2.5" Coil Spring Lift Kit
w/ 9550 VSS Shocks
 

The JK 2-Door/JKU 4-Door 2.5” Coil Spring Lift Kit w/ 9550 VSS Shocks, however, has its advantages and benefits. The Performance Spacer Lift Kit adds a spacer block, while the 2.5” Coil Spring Lift Kit adds active coils that provide increased suspension and spring travel. The springs help with upgrades such as a winch in the front or a heavier spare tire in the back making the weight gain less problematic. This lift also includes a beneficial lift in the front to improve the nose-down factory rake.

So, for the weekend warrior out to do some fishing and maybe some light trail use, and still needs to get the kids to football, the 2.5” Performance Spacer Lift Kit or 2.5” Coil Spring Lift Kit is probably all you need. 

For those who want just a bit more with their 2.5” lift, we offer the JK/JKU Sport S/T2 Suspension System which adds Sport front lower flexarms and bump stops and a choice of Falcon shock absorbers. 

.2.5" Lift Sport S/T Suspension System
w/ Falcon 3.3 Fast Adjust Shocks

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“That’s going to get you where you want to go. It’s going to allow you to run a bigger tire and give you a great ride.” 

However, those who decide to go big will need a lift with some adjustability to correct geometry and to save their driveline from an otherwise short and painful life. If we want to be rough and tough, we have to pay to play. Bigger lifts require more components and added costs. 

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3" Lifts

3" Lift Suspension System w/ 4 Flexarms, Track Bar,
& 9550 VSS Shocks

 

For example, TeraFlex has a kit that includes only four arms, the JK 2-Door/JK 4-Door 3" Lift Suspension System w/ 4 Flexarms, Track Bar & 9550 VSS Shocks. This kit includes preset Sport front lower flexarms and preset Sport rear upper flexarms. The longer front lower flexarms restore proper caster angle. 

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When lifting a vehicle with a solid front axle, one must pay close attention to the caster angle and pinion angle. Since these two angles are fixed, there will be a compromise between them. Generally, the pinion angle becomes steeper. Although caster isn’t a factor on the rear, pinion angles on both front and rear solid axles must be adjusted so that the driveshaft is pointed directly at the transfer case in order to reduce driveline vibration and U-joint strain. 

WHEELBASE

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3" Lift Alpine CT3 Suspension System
w/ Falcon 3.3 Fast Adjust Shocks

 

As a vehicle is lifted, wheelbase decreases due to the arc of the arms. One way to compensate for this issue is to buy a kit with 6 or 8 flexarms such as the JK/JKU Sport S/T3 Suspension System which adds Sport front lower, rear upper & rear lower flexarms, which centers the front and rear axles in the wheel wells to restore the factory wheelbase. This kit also includes bump stops and choice of Falcon shock absorbers. Sport front upper flexarms are available separately. 

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For more control over vehicle caster, we offer the JK/JKU Alpine CT3 Suspension System which adds a full set of Alpine adjustable flexarms and choice of Falcon shock absorbers. Our JK 2-Door/JKU 4-Door Outback Overland Suspension System adds heavy-duty coil springs to handle the additional weight of supplies necessary for extended overland excursions. Other upgrades include heavy-duty suspension limit straps and coil spring retainers. 

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Although we recommend the same 35” tire with either a 2.5” or 3” lift kit, the additional 0.5” adds more ground clearance. 

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Swenson approaches a large obstacle in his coworker’s 2010 JKU with a 2.5" lift kit and 35” tires. The approach angle clears as he drives the front tires up the wall of the obstacle. 

“I hear the hitch dragging, but that’s it,” Swenson says. 

The front tires reach the top of the obstacle, but as he attempts to continue climbing, the Jeep doesn't move.

“What’s happening underneath is that the break over angle is too great on this obstacle to get this Jeep up and over, because of the wheelbase.” 

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With its shorter wheelbase, a 2-door JK with the same 2.5” Coil Spring Lift would have easily cleared that obstacle because of the increased break over angle, which decreases the chance of the belly hitting the edge. Wheelbase length can work for us, as well as against us. A 2-door build will not need as much lift as a 4-door to clear the same obstacle’s break over angle. However, that longer 4-door wheelbase will shine on a steep incline and approach angle. That’s the nature of wheelbase – one must take the good with the bad. 

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Swenson explains, 

“Really the way you want to build your rig is you want to figure out: ‘What is it that I want to be able to do, the trails I want to do, and the ease that I want to do it with?’ And that’s how you outfit your vehicle.”

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1.25" Body Lift

TeraFlex asked Hank, a brand-new Jeep owner, about which lift he's considering. He said:

“I’ve done a ton of research, and there are a couple of looks that I like. I really like the big look, but with my budget, I’m thinking a 35” tire. But I don’t actually want a 35", I want at least a 37". I’m just not sure what that entails.”

TeraFlex professional Dennis Wood offers guidance:

.1.25" Body Lift Kit 

“You can run a 37” tire on a 3” lift. With a 37” tire we need to be able to move that tire back and forth in the fender well. The tire needs to go to the center of the fender well, so it can go up and down as you ride without rubbing.”

“And you’re saying with a 3” lift, I can actually adjust that?” asks Hank. 

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“As long as you’ve got all eight Alpine adjustable flexarms,” Wood replies, suggesting: “There’s one more option we could do that would work a little easier, and that’s to throw in a 1.25” Body Lift Kit.”

“Wait a minute,” Hank hesitates, “a body lift? Now I don’t want it looking like a Suzuki Samurai.”

“I understand," Wood responds, "but I’m only talking 1”. That way if you did a 3” lift kit, we can run these stock drive shafts. That’s going to save you maybe $1,000.

"The 1.25” body lift helps keep the center of gravity lower by keeping the frame and powertrain that much lower. However, manual transmission equipped Jeeps need to consider the feasibility due to additional modifications that will need to be made. That being said, a body lift will not improve frame clearance or break over angles."

Hank lights up, “So basically, I can take the money I would invest in a drive shaft and put it toward the tires." Hank smiles. "That'll keep the wife happy.”

Wood confirms, “You’ll save some money on the lift, you still get the bigger tires, it will look good, and you will love the difference.”

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Lift Size: Go Big or Small?

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Meanwhile, Joe Thompson expounds on his “big” perspective:

“I think you can do a lot of things with the small lifts, it’s just that those don’t fit my personality or what I want out of a JK. The small lifts have a lot of advantages, you know like better gas mileage and easier to get into. But the problem with those is that, in my opinion, they’re plainer looking. They get more lost in the crowd. I like a vehicle that stands out, that’s got some personality to it.”

Jeff Mock chuckles:

“Well there’s a lot to be said about ego, and there’s nothing wrong with that. If you like the stance of a Jeep with a taller lift, hey it’s your Jeep. Do what you want with it. But there are a lot more geometry issues when you go taller.”

Referring to Mock's statement, Engineer Calvin says:

“If he wants it to be quicker, if he wants to run the smaller tire, there’s no reason for him to go with a bigger lift. If you start running a large 37” tire, it’s going to rob you of horsepower.” 

Calvin explains that one of the advantages of keeping it low when pre-running is the lower center-of-gravity. By running a shorter and smaller tire, the acceleration will be much quicker. 

“On the other hand, when you're looking at riding a rougher trail, a 37” tire offers a more capable rig. But someone like Jeff Mock, he’s not interested in running that type of trail. Jeff Mock will not only be happiest with a smaller lift and tire, but he’ll also have an actual advantage for his personal preference of Jeep use and lifestyle.”

Swenson, owner of the 40” tire, comments, 

“To me, a bigger tire is better. If you can manage to stay low and clear a bigger tire, I think that’s going to benefit you more.”

4" Lifts

4" Lift Suspension System w/ 8 Alpine Flexarms, & Track Bar
(No Shocks)

 
Calvin comments on the JK 2-Door/JKU 4-Door 4” Lift Suspension System w/ 8 Alpine Flexarms, Track Bar, & 9550 VSS Shocks:

“When you run a 4” kit, you’ve got two choices: You can do a short arm kit or a long arm kit. The advantage of our short arm kit, is it’s probably the most cost-effective way to get that 37” tire under there because you’re just mounting to the factory mounts on the frame.”

The engineer explains that once a long arm kit is chosen, for example, the JK/JKU Alpine CT4 Suspension System, the geometry changes so much from the factory geometry, that a more drastic correction is needed. This is done by cutting off the factory control arm mount brackets, and welding on new mounts which will shallow up the angle of the control arm. 

“That’s going to put the geometry where we want it so you’ll get a better ride on the road and off the road.”

.4" Lift Alpine CT4 Suspension System
w/ Falcon 3.3 Fast Adjust Shocks

 
 

Thompson, who runs a 4” lift with a 37” tire on his JK, says: 

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“All the advantages of the taller kit over the lower kit are about the ground clearance. This is my tallest Jeep I’ve ever owned. I’ve had it since 2012. I like the looks. I like the clearance.”

Further commenting on the 4” long arm kit, Calvin says:

“It’s a big jump up in performance from the short arm kit, especially when we’re talking 4” of lift. You really need to do some correction to the suspension dynamics.”

Mock reaffirms the engineer’s words, stating:

“Anything around 37” or 40” tires, you’re really getting into axle issues, gearing issues, drivetrain strain, engine power issues, and you can’t really do that many more trails. And the trails that you do run, chances are you’re going to get some body-damage.”

Swensen states:

“Obviously, it’s big. You have to build it to withstand the abuse it’s going to take.”

Thompson describes his Jeep build which sustains his large tires and lift height:

“I have a 4” long arm kit running a TeraFlex Tera44 front axle with 5.38 gears and an E-locker. I have a TeraFlex CRD60 [rear axle], also with an E-locker. There are 4 speed bumps; in the front and in the rear. I like all the compression range with 4 speed bumps."

Driving his Jeep, Thompson approaches the same obstacle which Swenson failed earlier in a 2.5" lift. Thompson comments as he drives:

“I’m going to come up to this obstacle slow. I don’t want to ram it. I want to make sure my bumper clears it.” His tires reach the approach angle. “Looks good. I’ll give it a little gas.” 

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He crawls to the top with ease.

6" Lifts

Calvin continues to describe the dynamics of yet a larger kit, for example, the JK/JKU Alpine CT6 Suspension System. He explains:

“You’re going to be running a bigger tire if you’re running a 6” lift. You’re going to be running a 38” or 40. With 37-40" tires, the gearing must be modified. You’ve got to gear it down in order to compensate for that bigger tire.”

6" Lift Alpine CT6 Suspension System
w/ Falcon 3.3 Fast Adjust Shocks
Calvin also explains that the stock axle can be used with new gearing, but the problem is that a larger tire in diameter allows more leverage to break that axle. Another problem with a taller lift is the abundance of air passing underneath the vehicle. Objects are hanging down, obstructing a smooth passage for the air. This will result in increased turbulence, drag, and decreased fuel efficiency.

 

This may be perfectly fine if you’re like AJ Swenson who runs the 6” lift. 

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“I didn’t buy a Jeep for gas mileage, but with this new Jeep I’m actually getting 16.8 mpg. With CRD60 axles, of course, I have a manual transmission, and that helps a little bit. But still, I have no complaints with gas mileage. Obviously, you won’t get the stock 20 mpg, but I think that anyone who is lifting their vehicle will realize, hey, bigger tires, heavier tires, thicker gears, it takes a lot more to turn those.” 

Obviously, Swenson is more interested and concerned with his experience off-road.

The practical reasons for a bigger lift are all found on the trails. The approach angle will be steeper and better. Tires will hit a rock ledge first instead of the Jeep, and the bigger tires will provide more leverage, moving the Jeep up the face of that rock. On a departure angle, coming off a ledge or down a boulder, body damage will be avoided. Larger rocks passing underneath can be straddled with ease. Driving can be handled less carefully, and things can be done off-road that other vehicles can’t.

Mock says:

“I’ve had Jeeps with the Hemi[engine]s, 5” of lift, the [Dana] 60 axles, and they’re good. They’re a lot of fun. But for the actual utility and being a grocery getter at the same time, and being able to take it around town all day, the 2.5-3” lift on a JK is much more everyday user-friendly.”

Thompson states:

“I like to go fast in between obstacles and be able to choose if I want to go slow or if I want to fly up. To me, the 4” kit is the best mid-range kit there is.”

Swenson concludes:

“It is very smooth, no bumps, no death wobble. I am extremely happy with the 6" setup."

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There are some great companies out there that make great lifts. Some drive well on the road. Others drive well off the road. The trick is finding one that will drive well on and off-road, which is where the TeraFlex advantage comes in.

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Check out all of our TeraFlex Suspensions Lifts, Off-Road Performance Parts, and Jeep Accessories HERE!

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– Edited by Jason Udy

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