Factory ground clearance on a H3 Hummer is less than ideal at 10 1/2 inches, which is why it constantly gets hung up on the cross-members and looks like a turtle. I was disappointed, to say the least, when I realized just how far I had step backwards with my H3 Hummer compared to my previous vehicle. The feeling is a terrible one, but I know in my heart that not enough work has been done yet to the H3 Hummer before I will throw in the towel.
The first step to gaining better ground clearance with the H3 Hummer is bigger tires. Normally this is the second step for most most vehicles. However from the factory, the H3 Hummer can fit massive 315/75r16 tires with out any problems. I personally can’t find a single good reason to go any bigger than 35 inch tires. So I choose to go with General Grabber Red Letter 315/75r16 tires this time around because I wanted a tire that was more road friendly than my past choices. While these tires aren’t the quietest tires at this size, I feel that they a great compromise between on road driving and great off-road performance.
Next up is to raise the front-end of the Hummer up by tightening the bolt on the torsion bars underneath. The best part is that this costs nothing to do, however the Hummer will need an alignment to correct the steering geometry. Some companies like to offer “torsion keys” when cranking on the torsion bars, but these things are the same as buying snake oil. Once I raised the H3 to desired height, I was surprised with the ride quality seemingly improving. I think this is because the front bump stops no longer rest on the control arms and allow for more up travel. This has me thinking that GM intend for this adjustment to happen.
At the same time you raise the front-end by cranking on the torsion bars, I recommend getting extend shackles for the rear suspension. Extend shackles are dead simple and have been used for years with off-road vehicles. They replace the weak factory shackles, raise the vehicle, and allow the rear end to do more work off-road. There is a small problem that everyone should be aware of when putting extended shackles on a H3. The shackles raise the ride height and extend the factory shocks to a position outside the factory specs and this can lead to damaging the shocks from over extending. However, if you happen to have the H3 Hummer high clearance leaf spring mounts, the shock is relocated higher up in relationship to the axle and puts back in the factory specs.
With all work done to my Hummer I was able to get up to 13 inches of ground clearance, which is 2 and 1/2 inches over factory. I didn’t take any measurements when I had my General Grabber tires put on, but I did take measurement when I put the lift on. My front fenders where 38 inches off the ground directly above my tire, and afterwards I had 39 1/2 inches. The extended shackles took me from 40 inches up to a total of 41 1/4 inches. The front bumper came up to 20 1/4 inches and when matched with the 315/75r16 tire, the approach angle improved greatly.
The difference of 13 inches over 10 1/2 is very noticeable driving off-road, and considering the price… it is worth the trouble. I would like to get the ground clearance up around 15 to 17 inches, but it will require more work because I believe the Hummer shouldn’t sit any higher.