http://www.detnews.com/apps/pbcs.dll...706270330/1149
.... they took a standard Hummer H3 and did some modifications that can serve as a template for anyone interested in taking his or her H3 more toward the extreme of off-roading.
Two things the engineers needed were: increased ground clearance and clearance to mount a set of LT315/75R16 tires that are 35 inches in diameter. The standard H3 comes on 32-inch tires.
Going to 35-inch tires was vital to the work the engineers needed to do, said Todd Hubbard, H3 vehicle dynamics engineer.
Hubbard added that 35-inch tires also are something that serious off-roading H3 owners will want to consider. However, he suggested those owners not go to the extremes the engineering team did. Instead, he said all they really need to do is to do a one-inch body lift, which can be done with a dozen one-inch spacers and longer bolts.
He noted that the H3 brush guard can be adjusted to hide any resulting gap at the front of the vehicle and that the H3 fan shroud can be rotated to prevent the possibility of rubbing.
Hubbard said this setup is practical and maintains a lower center of gravity than the more extreme measures on the engineering truck, which features a four-inch Rancho front suspension lift (see
www.gorancho.com).
After installing the kit, GM engineers and technicians at the Milford Proving Grounds modified the H3's rear suspension -- inverting some factory parts and fabricating others -- to raise the back end level with the front.
They also installed an electrically locking front differential, which is not yet available on the H3, and the wheel flares that are standard on the H3 in some overseas markets (those flares can be ordered through any Hummer dealership, Hubbard added).
Those flares were needed to fully cover the larger tires, which the engineers mounted on two-piece bead-lock wheels that were originally built for use by the Border Patrol. Off-roads often need to air-down their tires for enhanced traction and the bead lock setup means tires can be run at zero air pressure if needed. However, the wheels the engineers selected had to be modified to fit the H3 lug pattern and to provide the proper offset. Hubbard suggested that H3 owners should be able to find wheels for their 35-inch tires through standard off-road aftermarket suppliers.
The result with either with the simple one-inch lift or the more extreme Rancho package should be an H3 that takes its off-pavement capabilities to the extreme.