So your considering upgrading your H3 Suspension System...

[Talljeeper]

Seems Tim and I have a little difference in opinion when it comes to the currently available Rancho system. There also seems to be a vast chasm of knowledge an expectations regarding what to expect if your considering modifying your suspension.

Here are some pretty basic facts about things to consider before you lay your money down and start turning a wrench.

Begin by becoming famliar with fourwheel drive systems. Having written for Four Wheeler, Four Wheel Drive, Off-Road and 4-Wheel & Off Road, over the years these publications will help familiarize you with some great information. There are common laws of physics that apply to ALL altered four wheel drives. These publications will help you make informed decisions and more importantly ASK informed questions.

If you increase overall tire diameter ( say from 33" to 35", you impact;
Braking performance (by increasing overall rotational mass weight.) Imagine the physics of trying to stop a 30# kid swinging on a swing set vs. a 70# kid. It takes more force to stop the inertia of the 70# kid. The same thing applies to rolling tire AND wheel combo. One vehicle I bogged had rice cane combos that were over 400# each. Not only did I have to upgrade the axle brakes but also custom build a driveline brake to compensate for the weight and stop the beast. The point is you cannot change the laws of physics.

Gear Ratio - improperly geared you will turn your poor little 5 cylinder into a four popper...well almost.
By adding the additional tire diameter you're essentially turning your 4:56 gears into a 3:73 ratio, or there abouts (I haven't done the math but would be happy to if requested). The I-5 is supposed to operate within a very specific range of operating conditions. By altering overall gear ratio you WILL impact negatively, acceleration, off the line torque, transmission cooling and operation,fuel mileage, speedo (can be recalibrated) and cooling efficiency. The only way to correct this is to perform a ring and pinion replacement. Period. No amount of engine add-ons can compensate for a poor power curve grenaded by tall tires. There is a point of no return when it come to oversizing tires.

Tires and wheels...the mystical beyond... LOL
I have seen some pretty curious questions....
"can I run a 12.50 on a 7.5" wheel...."
Confusion over the term backspace and offset...
How rim width impacts the overall stance of backspace at the axle.....
Choosing design because they look cool and without regard to proper fitment.

Anytime you are considering a tire and wheel combo decide upfront what your are trying to achieve; traction, clearance, mud performance, snow/ice performance, street, etc... No tire performs well in every scenario. Thats a fact, but there are many good choices that provide a balance to perform well in "most" fourwheel drive environments. Large aggressive tires have many drawbacks that the novice should be aware of. They are hard to balance (this can be a BEAR to chase with shimmy problems and a lot of tire shops are not real friendly when it comes to rebalancing large tires check your area for GOOD 4WD tire shops)(many times a lift system will be blamed for poor performacne when in actuallity its the tires), wear fast, produce noise, and can impact ride comfort. So if your considering a TSL Swamper style tire be ready for dynamics not present in your OEM tires.
When it comes to wheels the only way to know for sure what fits and what hits is to try them on. When picking wheels choose three designs that you like EQUALLY well. Wheel mfg.'s often limit the wheel width, diameter, badckspace, centricity, and lug configurations within a specific wheel design. Never settle on ONE wheel design when getting ready to purchase. If its not in stock...WAIT till it comes in! The proper wheel for your H3 may or may not be available within a mfg product line or the one you like the best. Look at multiple mfg.'s.

Warranty issues - Some dealers are extremely averse to alerations made to vehicles, particularly suspension mods. just be forewarned. I have in many instances consulted with service managers outlining what I would like to do. This helps me gauge their reaction, and also get a a feel of what to expect in the event of a warranty claim.

Shocks - There are only two or three major players mfg'ing shocks, even though there any MANY companies offering proprietary or "signature" shocks. Hydraulic shocks, while cheaper are not usually the best choice. Gas shocks have MUCH better characteristics particularly for those that live in extreme hot/cold climates.

Lift Design - Any time you alter OEM suspension systems you are MODIFYING componentry. I have literally gutted ( cut, grinded, welded, bent, pounded, well you get it) Chevy's front ends to "install" lift systems....not fun. All systems have negatives limited to overall design. The more you go up the more modification is required. The more modification that is required the more areas for potential problems there are. If you are not capable of installing your own lift you will be pretty much at the mercy of retailers that sell and install specific product lines, unless you can find custom builders. Both have there drawbacks, but the key here is experience with not only the product but also your vehicle. Ask the question about problems that could arise related to the install and how well the installer will stand behind their service.

Altered center of gravity - Anytime you go up, you are impacting the overall center of gravity of the vehicle. You can compensate that by increasing the overall width related to the vehicle track width. Many prefer more narrow "look" but if your going up, go out as well to maintain stability, particularly in off camber 'wheeling situations. The H3 was designed with incredible center of gravity coefficients remember to try and maintain that balance.

Alignment - ALWAYS have you vehicle aligned after the initial install. Always re-tighten after 500 miles. In the case of any handling problems take the vehicle to an independant alignment shop. I prefer shops that have the high end Hunter digital alignment machines.



Hope this helps....