<%@LANGUAGE="VBSCRIPT"%> ROCKCRAWLER.com - 2003 Hummer H2 Technical Briefing
2003 Hummer H2 Technical Briefing


Hummer H2Can it Really Go Off-Road?
Unlike many of the SUVs on the market, the H2 is Rubicon-tested and has already proven itself a worthy off-roader in it's current Beta format. GM has taken these hand-built H2s over the Rubicon several times, proving that it can handle it and come out alive and driving. We wouldn't recommend trying that in many other of today's production SUVs.

With 9.4" of ground clearance, an approach angle of 39.8 - 43.6 degrees (depending on tire size) and a departure angle of 35.9 - 39.7 degrees, the H2 should be able to attack most obstacles that a typical four-wheeler would point it at. No, you won't see the H2 showing up at an extreme competition, but you certainly could take the H2 over the majority of the trails in the US, assuming it can physically fit.

The rear's departure angle is certainly less than, say, a Jeep Wrangler, because of it's rear cargo/seating area hanging out further. However, equipped with the optional air suspension, at a flick of a switch, the H2's backside will rise up two inches to help you clear obstacles.

The H2 uses a brand new transfer case built by Borg-Warner. The 44-84 allows a 40/60 torque split to the front and rear axles. The 44-84 is a full-time 4WD transfer case with a planetary center differential. This case allows five different settings:
- 4HI Open (dry road surfaces
- 4HI Locked (semi-slippery surfaces)
- 4LO Locked (severe off-pavement use)
- 4LO Locked + Eaton electronic rear differential locker (climbing and steep grades)
- Neutral (flat towing), 4 Lo Lock.

Hummer H2The Eaton electronic rear differential is a big plus for those who will want to really use their H2 off-road. We've used the ELocker ourselves in a Chevy Avalanche. The locker offers on/off operation at the press of a button. Operation is instantaneous and offers full lock between the left and right axle shafts in the rear of the truck. The ELocker will only work when the transfer case is in 4LO. It automatically disengages if you shift into a 4HI setting.

Helping out off-road, the Bosch 4-wheel ABS brake system uses their new Automatic Brake Differential (ABD), which is specifically calibrated to prevent unwanted activations when off-road. Other ABS systems can act unpredictably off-road, however, the ABD automatically adapts to the selected driveline configuration, even when rockcrawling or mud bogging. The system senses wheelspin and depending on the transfer case settings, can supply braking to up to three wheels, thus sending 100% power to a single wheel that has traction.

Will the H2 crawl? Well, crawling is all relative. The H2's ratios add up like this: The 4L65-E 4-speed automatic transmission has a 1st gear of 3.06:1. The Borg-Warner 44-84 Transfer Case has a low range ratio of 2.64:1. The axle gearing is 4.10:1. Multiply these ratios together for a final crawl ratio of 33.12:1. Compare that to a Jeep Wrangler's stock ratio of 27.80:1 (automatic with 3.73 gears) or the upcoming Wrangler Rubicon's amazing 65.92:1. The H2's crawl ratio is certainly respectable and much lower than most other SUVs on the market and should be low enough for most owners.

Once you've gotten the H2 off-road, you'll need underbody protection. Hummer has built in skid plates for under the motor, fuel tank, and transfer case. Frame-mounted bars protect the rocker panels and an intermediate ladder helps keep the rocks away from the transmission.

Hummer H2Final Thoughts
When we first saw the H2 concept back in 2000, we wondered first if it would ever be produced and second, whether it could actually go off-road and really get used. After seeing it in person and watching videos of the H2, we feel like it will definitely have a place in the upscale SUV market. Buyers of the H2 will be those who want to be different, live large, and be seen. We probably won't see a whole lot of soccer moms in H2s but we probably will see some. Certainly, most of them will probably be a lot more comfortable in a Lexus, BMW or Range Rover. However, those with adventure in their blood just might buy into the H2.

Now for those who actually want a real off-road vehicle, the H2 will certainly be a contender. With only a few other true four wheel drive, off-road savvy, SUVs left on the market, the H2 will not have much competition. The list is pretty short, really, and is made up almost soley by Jeep and Land Rover in the US, anyway, not including pickup trucks.

Even though the front end does not use a solid axle, the H2 has a good amount of wheel travel and has lots of flex in the rear. This coupled with the larger tires, a real transfer case, traction control and the ELocker should make the H2 quite the off-roader. Will it take on the competition trails of Cedar City, Las Cruces, and Farmington? Absolutely not. Will it go head to head against a Jeep Wrangler on most of the trails in the US? The answer is probably yes, assuming you don't mind scratching your paint.

If an H2 comes in at $50,000 then you can bet people will line up at the door. For the hardcore rockcrawler, the fifty large may be better spent on a Wrangler with all the goodies, such as axles, Atlas transfer case, lockers, etc. But for someone who wants a full-size truck, and more importantly, one with the Hummer name on it, the H2 is right up their alley.

We can't wait until summer to get our hands on one.



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