Wow! this is by far THE BEST artice that has been posted in this forum, thanks a lot for the link kacyk!! I would LOVE to get that lift kit... I think I'll try to get it from Santa :-)

Article start out with "Even though the Hummer H3 is considered the little sister of the larger H2"

WTF, heard it called the little brother but never the little sister

DUH !!! all this lift so he can install 285/75s ??? I've installed the 285s on stock suspension, and didn't even tweak the T-bar.

if you're gonna lift it, go all the way and put the proper 35 or 37 inch tires.

pics of my stock red H3 with 285s are in the "rim specs" thread.

SledgeHummer

The language in the article does not convey that 285/75-16's are stock on the Off Raod version of the H3.

They should have put these 35's on

Beautiful article on the design and installation of the lift components. The design is almost of what I had predicted for lifting the H3. One thing that is different, I didn't consider a coupler to tie into the torsion bar. I've seen the coupler design when the Toyota IFS first came out in 86. It didn't last or nobody bought the lift so another design came out.

Jagular7,

What do you think about 1st round production lifts? I'm tempted to do it but even the salesman said there may be issues in the beginning. I don't want to be a "test vehicle."

I know this may sound odd since I bought a first year production H3. But I had great luck on both H2's so I took the plunge. Suspension Lifts, however, I know nothing about.

I'm no expert so take what I suggest and digest. I've been wheeling since 1989, prior to that, I've been interested in motor vehicles, boats, go-carts, etc since I could turn a wrench (~9 yrs old). I'm an ME but not a designer engineer. I've never designed a suspension, but have installed, mod'd, customized my vehicles to work for me and what I want out of it.

So with all that, mass produced lift kits are just that. The designers mass produce a kit which can usually be installed by the typical owner or a somewhat equipped shop (not a full fledge custom design shop like a Nascar shop). The designer takes into consideration a large safety factor as they don't know how any driver/owner with the kit installed will be driving. The safety factor limits the design. With this in mind, the kit is usually bolt on or with limited welding.

Hopefully, the vehicle manu will have in place some quality manufacturing processes so as to limit any slight variances between 1 vehicle to another. But that's another story. For the basic lift on an independent front suspension, lowering the suspension frame locations and diff housing are the first thoughts. Then to compensate for differences in lowering between the components, ie upper and lower control arms, longer knuckles are added. If the vehicle has rack and pinion steering, the longer knuckle is necessary to keep the steering rack in stock location. The first generation of lift kits will try to minimize any changes from the stock manu's geometric design and function in the suspension and components. Second generation kits tend to provide changes in suspension cycling, ie droop and compression, better road street handling, etc. as it's a learning curve for lift manu's to learn how owners want to use their vehicle. (There is also the business of how long the vehicle manu will keep the vehicle in production.) But this leads to re-engineering the axles, upgrading to differential housing, the cvs in the axles, redesign of the steering tie rod (length, ends), among other smaller items. Do note: that going with larger rotating mass requires upgrades in axle strength, brakes, steering, etc. But this is all relative to the stock configuration. Also note, that by adding drastically change offset rims, this will change the front suspension. What this does is widen the front track width. The track width is the distance between the centerline of the tires from side to side and not the wheel mounting surface on the rotor. This will 'lift' the front due to the angles of the control arms.

The drop brackets for the control arms should be structured to limit any 'torqueing' force. Meaning the longer the distance to the static structure (the frame), more the torque force. Most kits minimize this in a 'bracket cradle' with rearward structure arms. Same for lowering the diff housing. I would say all front housings now have a removable 3rd member. This member houses the ring and pinion. With the ds rotating and applying torque, the pinion will try to walk on the ring and out of the housing. There is a lot of rotational force on that front snout and this needs to be addressed with the brackets.
Remember, the vehicle goes forward based on the torque is applied to the tires. The tires have enough friction to go forward without slipping. All this reacts on the frame and the components off the frame.

For the Rancho kit as an overall function, I'd say Rancho has started it off. Upgrades would be to eliminate the torsion bar setup all together and add coilover or even an air bag suspension. But that will cost more in design and test for any/all drivers for this type of vehicle. Lift kit manu's will tend to design for a specific user, thus each kit is slightly different. Figure 95% (probably bigger) who purchase a 4wd vehicle won't put it into low and take it off-road and actually get a scrape or two on the the frame, let alone anything else. So something like this Rancho kit will work.

Lastly, the overall travel (droop/compression) is only 2-3" (if that) at the knuckle (ball joint plane). This shouldn't change with any kit as this is originally design into the specs of the cv axle shafts and steering components. To get more droop, a lot of changes have to occur. Look at the desert IFS racers getting 20" of wheel travel for example.

If Hummer originally placed 35" or even 37" tires into the design of the H3, then its drivetrain components would allow it. I'd say they are pushing the envelope as a manufacturer (like Jeep with the Rubicon Wrangle model) right now, with the design changes they have from the Colorado platform. I'd have to guess that it's an agreement Hummer has with GM. Big business plays a lot in designing a vehicle from scratch or remodeling for certain market share. Figuring that most H3 Hummer owners won't take their H3 off the beaten path and onto actually off-road conditions. Recall the 95% factor.

Hope this helps in your decision thinking.