Tech Tips

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Jeep F.A.Qs

Here you will find some tech tips and helpful info to make your Jeeping experince more enjoyable.

Tire Tips

Traction and clearance are the two primary factors to consider when going off-roading. Your vehicle will have to maneuver over and around obstacles and through terrain. Choosing the right tire can give you an increase in both. A taller tire gives more clearance under the differential and chassis, and a wider tire, or change in tread pattern, can give more traction.

Tread Patterns
  The choice of tread pattern is important in your new tire decision-making process. Tread pattern should be chosen based on the intended use of the Jeep. The most popular tread pattern for all around off-road use is a mud terrain pattern.
  The mud-terrain or mud tire pattern is characterized by large lugs on the tire with large voids between these lugs. The large lugs provide plenty of bite in low traction conditions while the large voids allow the tire to clean itself by throwing off mud or other material when spinning thus providing a good bite on every rotation of the tire. These tires are also very popular for rock crawling as the large lugs can provide a way of gripping and pulling the tires up and over irregular rocky edges where a smoother pattern would just spin. The biggest disadvantage of these patterns is that they are usually louder on the freeway, or at higher speeds.
  The all-terrain tire performs well under a variety of off-highway conditions and to some extent has closed the street/trail performance gap. The general purpose all terrain tire generally has an interlocked tread pattern. The voids in these tires are also generally much smaller than those on tires designed for use in the mud. The denser pattern of blocks and smaller voids make these tires quieter on the street than mud terrain tires. The downside is that the smaller voids cannot clean themselves as easily of packed mud or slush as the larger voids on mud tires do. If these voids fill up with mud the tire loses much of it's "bite" and traction is lost. For general highway driving with minimal off-road use the all terrain tire is an excellent choice.

Tread Modifications
  There are several things that can be done to an existing tire to enhance its off-road griping characteristics. Two of the most common ways are siping, and grooving.
 Tire siping has trickled down from the trucking industry where getting some extra mileage from a set of tires is very important when you drive more than 100,000 miles per year. The basic idea of tire siping is to create extra biting edges in the tread the extra edges also serve to dissipate heat in the tire, which in turn will extend the tread life. Mud terrain tires will also be noticeably quieter on city streets. Siping involves making small cuts into the tire blocks, usually about ½' apart. These small cuts allow the tire to flex and conform to the ground easier than one large block.
&nsbp; Tire grooving is another option that is used to modify existing tread blocks, and can be used to make your own custom tread patterns. Grooving larger lugged allows the tire to take a better and more frequent bite out of the terrain. To see the benefits of grooving (and siping for that matter) look no further than the tires currently winning the major rock crawling series, tire grooving has become standard for nearly any competition crawler and your seeing a lot more grooved tires on many more tamed daily drivers as well. A grooving tool is much like a soldering gun; it heats up and slices through the tread block like butter. Because of how easy it is to make a cut you have to know what you are doing or you can destroy an entire tire in one motion. Also grooving too much can cause the lugs to get pulled off, or chunk off in some cases.
 One thing to note is that by either siping of grooving your tires, you may void the manufacturer's warranty. Also in some states it is illegal to sipe or modify the tread pattern of a DOT approved tire for street use. Overall siping and grooving does help and will improve traction both on and off-road, and will help to extend the mileage of your tires.

Optimum Tire Size
  Determining proper tire size for a vehicle and application can sometimes become difficult. Pay attention and you will see how simple it really can be. To do this you have to find out the maximum tire that can be fit with the current suspension lift on the vehicle. There are some variables to this also, such as what wheels are being used. The first thing to consider in a tire upgrade is fender clearance. Not only does your vehicle need sufficient clearance while at rest, but it must also accommodate maximum up and down travel and side-to-side tire movement caused by steering and cornering.
  Increasing tires size can greatly increase the off-road capabilities of your vehicle. Larger tires provide increases in total ground clearance, an increased traction footprint & flotation, make climbing obstacles easier, can be easier on the environment and just plain look better on your Jeep. However larger tires can affect other aspects of your vehicle. Larger tires are more expensive in general and may require expensive suspension upgrades for proper clearance, especially on the trail. Ring & pinion gear changes in the differentials may become necessary in order to keep your engine running in the optimum power range - especially when off-road, going uphill or driving on the freeway.
  Increased tire size also increases the torque loads on the axles, u-joints & drive shafts. When combined with other upgrades such as lockers, a weak link in your vehicle will show up, usually in the form of a broken axle shaft. If you are going to go with larger tires, be ready to potentially upgrade your axles and other important components. Bigger tires are heavier tires. This increased rotating mass and the increased leverage provided by the larger tire often call for increases in braking power: changing brake pad materials, rear disc brake conversions are all options. Driving a tall, short wheelbase Jeep with 35" tires and stock brakes in poor condition at highway speeds can become a recipe for disaster if not addressed or checked out!
  Tire diameter is not the only issue - tire width is important too. Wider tires increase footprint, which can be important for traction or increased flotation. Wider wheels or wheels with increased offset move the tires outboard and can greatly reduce the rubbing when turning but make the vehicle wider. This increased width may be an advantage for stability if you drive a lifted vehicle, but make your turning radius larger making it harder to make hairpin turns in trails. Overall wider tires usually are the way to go, largely because of the increased footprint it gives. If you are careful and do not over stress the rest of your components (axle shafts), you can run larger and wider tires without having to make too many other modifications.

Choosing The Proper Tire
  Tire manufacturers are doing a better job at providing specific tires for off-roading. Goodyear has made a large commitment to the rock crawling world with its MT-R tire line. The MT-R is one of the most technically advanced radial mud tire on the market today. The MTR matches the rocks with its puncture resistant Durawall technology. The outer lugs of the tire will shed mud easily, and when on the rocks will grip like fingers pulling the vehicle up and over just about anything. The side wall lugs allow your rig to crawl on the edge with durability and ease. As for the sidewalls, they are tough. Goodyear says this durability is due to the silicone used in the carcass and because its 3 ply. On city streets and highways, the tire is actually really quiet for a mud terrain tire. This is probably due to the fact of the alternating tread pattern that helps to keep noise level at a minimum. For one of the best mud terrain tires ever you cannot beat the Goodyear MT-R.
  If all out mud is your thing then the Super Swamper Boggers are the way to go. These tires were designed with mud in mind. Interco Tire Company has been making specific off-road tires since the 70's. Interco also makes several versions of rock crawling tires; the TSL, SSR and SX are all aggressive trail specific tires. They can be used for general highway use, but be prepared for them to howl at freeway speeds.

 Overall and by far the most simple thing you can do to your Jeep when going off road Is "AIR DOWN" you can run down as low as 9 or 10 psi depending on tire make. Usually 15 or so psi works well. When you air down, you are effectively widening the foot print of your tires as well as making them more pliable. In addition, you are making It way easier on your suspension components. Not to mention your hind end! You will be amazed at how much more comfy and capable your ride will be!  Just make sure you air back up when you return to the street. A soft tire on road Is very dangerous!

Suspension

There are a few basic factors that we use to help determine the type of and ammount of lift for your vehicle:

  • What the vehicle will be used for
  • Desired tire size
  • Your budget
  • Suspension type
  •   Many of our 4x4s serve multiple roles; it's primarily a daily commuter, with other duties being a weekend delivery truck, a little towing thrown in, and then trail rig. It would be nice to have a dedicated trail-only 4x4, but for many that is not possible or reasonable. With these 'multi-use' vehicles, the goal is to find the proper balance between on-road stability and off-road suspension flexibility. Manufacturer's like TeraFlex have taken the time to design suspension systems that work excellent for these 'multi-use' vehicles.
      A good suspension system will help your vehicle to perform well above a stock suspensions capability. This is because an aftermarket suspension system is designed to enhance off-road performance by maximizing flexibility, axle articulation and wheel travel. An excellent suspension kit will allow the vehicle to perform well on the trail and on the highway. The final center of gravity is a big concern. A 10" lift kit may look great, but has the potential to be very dangerous and potentially deadly if the newly raised center of gravity is not taken into consideration. A good lift kit will take all aspects of a vehicle's center of gravity and help to keep it as low as possible, while maximizing all other performance areas. Areas such as suspension articulation, breakover clearance, aproach/departure angles, and uphill/downhill/sidehill angles are all variables that will be changed with any lift kit.
      These modifications will allow the off-road enthusiast or trail rider to drive his vehicle on medium to hard trails and off-road conditions, such as deep mud, sand and rock crawling. A well prepared and balanced vehicle will be versatile and built for many conditions.

      A suspension lift allows you to run bigger tires and wheels for greater ground clearance and allow greater articulation or suspension travel, both up and down. Your ultimate goal is to achieve good articulation and to gain ground clearance, without giving up a good ride. Tire size is limited by the lift kit you choose, so if you want to run a specific tire size, plan ahead and get a kit that will fit that specific tire size.

      Budget is one of the main concerns for the 4x4 builder. Most suspension manufacturers offer a full line of products that fall into almost every price range. From the basic suspension kit to a full blown rock crawling specific kit, you can find something that will fit into your budget. Because price is such a common concern for many people suspension manufacturer's try to offer something for every price range. A simple budget boost from TeraFlex will give a 2" lift on a very limited budget, but they also off their top-of the line LCG (Low Center of Gravity) system that is for the enthusiast looking for a no-holds barred extreme system.

      There are two basic types of suspensions that are used by OEM manufactures, leaf springs and coil springs. Most Jeep vehicles produced before 1997 came with leaf spring suspensions, including CJ's (2A, 3A, 5, 7 & 8), Commando's, and YJ Wranglers to name a few. After 1997 most vehicles came with coil spring suspensions, including Grand Cherokees (ZJ & WJ), TJ Wranglers, and KJ Liberties. Some Jeeps like the XJ Cherokee came with a combination of front coil and rear leaf springs.
      Although there is much debate over what suspension type is the best, each has it's advantages. The leaf spring is generally more stable on side hills and tight turning, but create problems such as axle wrap, and wheel hop. These problems can be fixed with additional modifications such as a traction bar.
      The coil spring suspension has a particular advantage for off-roading, as it offers generous amounts of suspension travel and usually a smoother highway ride it also eliminates possible problems common to leaf springs, such as axle wrap, However without the help of a good sway bar system it acts much like a slinky, and wants to flop over on side hills and tight cornering. There will always be a debate about the 'best' suspension type, and generally what it comes down to is preference and vehicle loyalty.
      After your lift kit has been installed the vehicle will handle differently than before. There are many things that influence vehicle stability, for example: suspension type, lift type and height, tire type, width and air pressure, wheel/rim width and offset, vehicle curb weight and weight distribution, and more. Drivability traits will change, but the degree of change varies. A common saying is "the taller a vehicle, the easier it will roll over", but depending on how a vehicle is built makes it possible for lifted vehicles with taller and wider tires/wheels to be as stable or more stable than it was when it was stock. The key is to learn and become informed on the basics of suspensions, become aware of these new capabilities and limitations, and to drive responsibly. This will take some getting used to and some fine tuning in your driving style.

    Lockers

    The primary function of a differential is to transfer power to the wheels while allowing them to turn independently at different (hence the name) speeds. What this means is that when going straight equal traction is supplied to all wheels, yet while the vehicle is turning, the inside wheel, which has the most resistance and a shorter distance to travel when taking a turn, is able to go at a slower rate than the outside wheel which has the least resistance, a longer travel radius, and must turn faster.
      The most common differential is called an Open Differential and is the standard setup used for most Jeeps. This allows each wheel to turn independently of the other. Conventional open differentials tend to equalize the power delivered through both wheels. Thus if one wheel loses traction - "spins out" on snow, mud, sand, or gravel - it delivers very little power to the ground. The other wheel will deliver only the same very little power. Often this is not enough to keep the vehicle moving on - it's stuck. Some vehicles come with a limited-slip or posi-traction differential. While these are not a true locker, they do provide more traction than an open differential. They use various mechanisms to allow normal differential action when going around turns, yet when a wheel slips they allow more torque to be transferred to the slower moving wheel.

      Locking Differentials, usually just called Lockers, are for serious off-roading and trails. There are many different options when buying a locker.
      Powertrax offers the No-Slip and LockRight, they combine the smooth operation of a limited-slip differential, with the traction performance of a locking differential. you will hear a light clicking noise as the gears are overrunning themselves and allowing the wheels to differentiate in a turn. This is normal of most lockers on the market today. We recommend the Lock-Right for vehicles that are primarily driven in severe driving conditions or are used for recreational off-road. For vehicles that are driven daily or require more mainstream application, the Powertrax No-Slip offers a quieter and smoother performance.
      Detroit Locker offers lockers from their limited-slip True-Trac to the 100% locking Detroit Locker. The Detroit delivers power to both wheels, during turns it automatically 'unlocks' to allow the wheels to differentiate. The Detroit is notorious for it's loud noises (usually a bang) when it unlocks, but that is normal. It has been proven to hold up under some of the most extreme conditions and is a regular locker chosen by top rock crawling competitors.
      ARB offers it's selectable air locker that acts either as a fully engaged locker or an open differential. It is operated by compressed air and selected on or off by an in-cab switch via an air compressor.
      TeraFlex also offers the new T-Locker, which is a selectable air locker. T-Locker has no seals on rotating parts and uses a shift fork that is operated by an air actuator on the outside of the differential cover. Like the ARB it is controlled with an in-cab switch.

      Once you've purchased a set of lockers and had them installed, here is a short course on how and when to use them. Whether you have air, electric or mechanical lockers, limited slip, posi-traction or whatever, the techniques are generally the same.
      A rear locker alone will give your vehicle more traction, and will be one of the best and most noticeable improvements on a 4x4 vehicle. When climbing it will keep traction and help to push you to the top. The locker will require you to re-learn some aspects of off-road driving. In mud and soft dirt/sand the rear locker will steer you straight, even though you are turning the front tires! This takes some getting used to and may now require some three point turns, where they previously were not needed.
      Steering with a front locker is hard to do especially on hard surfaces like slick-rock, granite faces and boulder outcrops. When you try to turn, the lockers will hinder your turn, sometimes it will seem like you cannot turn at all. This is because the locker is keeping both wheels turning at the same rate, and in essence making you go straight. Selectable Lockers (ARB, Tera, etc) are really good for front applications since they can be turned on or off easily.
      Overall having lockers means you need to pay more attention to the vehicle and its handling characteristics, if you don't things can get ugly fast. When driven responsibly, lockers are a great help. They actually reduce environmental abuse due to all four tires helping, not just two spinning.

    Shocks

    Shock absorbers control the amount of bounce your vehicle has in response to bumps. They resist movement, and help reduce body roll. In other words, their primary purpose is to eliminate unwanted and excess motion between the vehicle body and suspension and help keep your tires on the road. When aprings are compressed or stretched they bounce, and shock absorbers help control the springs from bouncing uncontrollably every time the tires encounter a bump or the slightest road or trail imperfection. Shock absorbers also play a critical role in vehicle stability and safety. Without shocks, tires would lack adhesion and braking, and cornering would be almost impossible.
      With each extension and compression of the shock, called a "stroke," a piston moves up and down inside a sealed tube filled with hydraulic fluid on one end and a movable piston rod which, in one way or another, controls and allows the fluid to be pushed through a valve at the end of the rod. The valve opens and closes, depending on the direction of the flow and is designed to provide a measured resistance to the flow of the hydraulic fluid. When vehicle movement causes the shock to extend and contract, the valves open and force is generated. Because the oil/gas cannot be compressed, only a certain amount of fluid can be forced through these valves, which creates resistance to the vehicle movement. The drawback to an oil shock is that when an oil shock is used rigorously (like on a bumpy dirt road) bubbles form in the hydraulic fluid. This foaming, reduces the ability of shocks to provide resistance and prevent bounce. Gas charged shocks are superior to regular hydraulic shocks because air in the shock is replaced by pressurized nitrogen gas. Gas shocks also quicken the response of a shock's movement thereby increasing comfort and control under all conditions.

      Under normal conditions, shocks & struts wear out gradually. However, many factors can affect how much wear is actually occurring and at what rate it is occurring. If the shocks are used heavily off-road, and at high speeds. The piston rod can easily be nicked or damaged by flying gravel allowing grit and dirt to damage the piston seal. When this occurs, fluid begins to leak from the piston seal and eventually the shock will lose its ability to function properly.

      Here is a good self test to check for signs of worn shocks:

  • Bounce the vehicle, and let off. If it takes more than 2-3 bounces for the vehicle to stop moving your shocks are probably ready for replacement.
  • When stopping quickly, does your vehicle rock back and forth several times?
  • When changing lanes quickly does your vehicle rock or sway from side to side?
  • On a lifted 4x4 it is harder to tell if shocks are worn out, because they inherently have more body roll than normal. However, if it feels excessive chances are that the shocks are worn.
  •   To visually check for signs of a bad shock use these tips:

  • Check for oil collecting around or on the shock, or rod.
  • Check for bottoming out of shock. The piston rod will show the collapsed length of the shock. If you can see a dirty part of the piston rod you probably have not bottomed out your shocks. If cannot see any collected dirt or dust on the piston rod then your shocks are probably bottoming out on compression cycles, and the shocks internal valves may be damaged.
  • Check all mounts. If the shock is loose it will not function properly. High speed dirt roads and other vibrations can cause bolts to come loose. Regular maintenance can help to prevent a shock coming loose on the trail.
  • Broken or damaged piston rod. If the piston rod is bent, or damaged it can not function properly, and will allow oil or gas to escape from the seal when it is cycled.
  •  

    Sway bars

    Sway bar diconnects create heated discissions among off roaders, but the fact reamains that for off road, low speed use,The disconnected sway bar our performs any connected one. When you remove or disconnect your bar you effectively "loosen up" your suspension and let It work. The front end will gain "much" more articulation and also soak up rough terrain better, as well as neutralizing that body thumping side to side rock and roll action. At the end of the day you will feel a difference!


    The amount of additional suspension travel gained with the front swaybar disconnected is dramatic - at least 30% in most cases. This proved more than enough to ensure constant contact between tires and terrain in the majority of off-road situations.

    Furthermore, rear suspension performance also improved off-road when the front swaybar was disconnected. Without any modifications, the smaller less-restrictive rear swaybar could operate more effectively due to the additional leverage created by the front suspension.

    Before you take our word for it and spend the extra cash, simply try it on your next off road adventure just unbolt yyour stock swaybar and tie it up out of the way and see for yourself what a difference it makes. Always be safe and reconnect your swaybar before driving on road at higway speeds as it does take some getting used to on the road and can be dangerous.