some H2 fast facts (Full Version)

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some H2 fast facts

  

Greenblade -> some H2 fast facts (5/23/2006 2:30:02 AM)

A bit of how the big-bad offroading SUVs stack up on paper

Ground clearance (per spec)

H1: 16"
H2: 10.8" (with air suspension engaged)
Wrangler Rubicon: 10.3"
Mercedes G class: 8.3"
H3: 9.1" (with optional offroading tires)
Range Rover: 10.8" (with maximum boost)
LR3: 9.5" (max boost)


Approach angle:

H1: 72 deg
H2: 43 (w/air suspension engaged)
Wrangler Rubicon: 44.9
Mercedes G class: 36
H3: 39.4 (w/offroading tires)
Range Rover: 34 deg (w/max boost)
LR3: 37 deg (w/max boost)


departure angle:

H1: 37.5 deg
H2: 40 (w/air suspension engaged)
Wrangler Rubicon: 33.9
Mercedes G class: 36
H3: 36.5 (w/offroading tires)
Range Rover: 26.6 deg (w/max boost)
LR3: 29 deg (w/max boost)


Breakover angle:
H1: 29 deg
H2: 27.5 deg
Wrangler Rubicon: 25.4
Mercedes G class: don't know
H3: 25 deg
Range Rover: 30 deg (max)
LR3: 28 deg (max)


I take polite issue with the ground clearance spec for the rubicon based on the ones sitting int he local dealer lot. They aren't nearly as high-off-the-ground underneath as an H2, and i'll take photo/measurements to make the point and post them on sunday. But whatever, just taking everybodies word for it and not actually measuring the vehicles, the H2 is as good as it gets.

The land rovers have a higher breakover angle, but at expense of poor for this group approach and departure. The H2s clearance owes apology to only the H1.


Suspension travel and 4wd features would be good to add, i think, but i can't find enough info/aren't knowledgable enough. The H1 has optional 4 wheel locking, the rubicon has that, the H2 has rear/center locking, the G500 has 3 locking diffs, the LR3 has center/rear lockers, the Range Rover has no specs at all for alot of the offroad stuff including this (as far as i can tell at landroverusa.com ) and the H3 has center/rear lockers. So the H1 and teh rubicon maybe have an advantage there?? The h2 also have a very advanced computer controlled traction system that you can watch working when you put the big truck to task, some of these others may also, but probably not the Jeep (low $$$).


Height/track width/curb weight
H1: 77 / 72 / 8100 (wagon) ratio = 0.935
H2: 79 / 69.4 / 6400 ratio = .88
Wrangler Rubicon: 71 / 59.5 / 3800 .838
Mercedes G class: 78 / 59.6 / 5,550 .764
H3: 74 / 65.5 / 4700 .885
Range Rover: 75 / 64 / 5500 - 5900 lbs .85
LR3: 74 / 63 / 5100-5800 lbs .85


So here the hummers are 1st-through-third in guesstimates of stability based on width to height. Its not that simple, i know, but the width -vs- height of center of gravity will be the defining aspect of angular stability and what not. The H1 is king, H2 and h3 are next, and the G is the highest to its width ratio by quite a bit. whatever thats worth




So, by the numbers (and these things are very important, if your approach angle isn't adequate, you'll shove your nose into something, if the departure isn't, you'll clank your bumper. but what do i know? ) the hummers fare very favorably.

The basic 4wd goodies seem to be about the same as well. What else is there? tires i guess. the bigger the better, at least for some things. i think? that seems to be one of the first steps when making a non-jeep offroading machine (chevy 350, lift kit, etc.)


This stuff is very entertaining to me, because you can read the review of any of 1000 or so flaming nuts, who've never set foot in a hummer, much less offroaded with anything, talk about how its worse than a 2wd Explorer (actually read one guy explain that he'd been in the army, and knew humvees like nobody, and his 2wd explorer could easily outperform a humvee. zoinks )

ok


  
shortbus -> RE: some H2 fast facts (5/23/2006 10:07:02 AM)

you and dennis been hanging out or something? that's way too much detail. . . .[sm=headbang.gif]

Dennis -> RE: some H2 fast facts (5/23/2006 10:12:12 AM)

Whatchu talkin about Willis?...I was just going to comment on how well he compliled the data..In fact, I copy and pasted his post to a word doc for future reference..[sm=proof.gif][sm=smiley20.gif]

Greenblade -> RE: some H2 fast facts (5/29/2006 5:47:46 AM)

'mornin. before talking about off-roadin stuff, i thought i'd mention that if i drove a '95 Civic i could realistically work alot less than i do. Or is it because i work alot that i drive a hummer? yeah, that's the one.

some of the basic traction stuff

Differential locks
H1: optional package would give it front/center/rear diff locks. center lock is standard
H2: center/rear lock is standard
Wrangler Rubicon: front/rear/center all 4wd modes have locked center
Mercedes G class: front/center/rear
H3: center/rear on all models
Range Rover: center only (other sources have said it has no locks, limited slip center differential only)[sm=bustedsign.gif]
LR3: locking center, optional locking rear differential


The H1 and H2 have similarly-described traction control systems. The systems use the brakes to slow free-spinning wheels allowing the differentials to send torque to wheels with traction. a 10% grade can be climbed with 3 zero-traction wheels. The H2s is said by hummer to be "perhaps the most advanced ever offered in a commercial vehicle", so perhaps they consider it better than whatever the H1/Humvee uses. The H2 also has the option of reducing the effect of this system, allowing more free-spin in the tires to spin your way through sand, mud, deep snow, and other such muck. Standard torque distribution in the H2 is 40/60 front/rear.

The H3 borrows from the H1 and H2 and offers a similar constantly-computer controlled traction control system.

The G500 has user-selectable diff locks -vs- the H2s more limited possibilities. The H2 offers rear diff lock only in combo with center diff lock, in the G500 you can choose whatever combo you like (my understanding). i'm not sure if that's useful or not, it seems like by the time you need the rear and/or front locked, locking the center would be a given... The G500 utilizes a system akin to that in the hummers - brakes slow spinning wheels... In the G500, this system disengages when any differential is locked. Default Torque split is 50/50 in the G500

The Wrangler Rubicon offers electrically switchable from-cabin locking. when four wheel drive is engaged, it has a 50/50 torque spolit. it doesn't have any electronic goodies help you along in the rubicon, but, then, its alot cheaper. to counter the "its alot cheaper", its by far the least practical - seating and cargo room - of the lot, the lowest (save mebbe some H1s on the road) comfort/luxo, and its by a huge margin the loser in the "coolness" or "status" element of a vehicle purchase when tossed in with this group. they are freaking everywhere, including at least 4 at any given college bar on any given night. And frankly, i don't think that a $32,000 rubicon is remotely better bang-for-the-buck than a $64000 H2, much less a "base" level H2 (which comes with all the goodies but the air suspension)

The RAnge Rover can shift into 4-lo on the fly, has 4-wheel electronically controlled air suspension that is from what i understand faster and more advanced than the optional air suspension on the H2. it has more electronic goodies than any of the other trucks including a hummerish traction control system and more, from hill descent control to terrain recognition software, and a really pretty (i LOVE it) computer display discussing these things. but with no front or rear diff locks & crappy angles, maybe its safe to say the Ranges intended goal was petering around the pasture, and not tackling the ridiculous things.

The LR3 seems to have most of the goodies of the Range, but with optional locking rear diff. I read in 2 places that the Range offered no center lock, but just a limited-slip center diff.


Axels/suspensions
H1: 4 wheel independent
H2: independent front, live rear
Wrangler Rubicon: live front/rear
Mercedes G class: live front/rear
H3: independent front/live rear
Range Rover: ?
LR3: ?


I have a question for people with H2s an

Greenblade -> RE: some H2 fast facts (5/29/2006 5:49:21 AM)

the reviews and "showdowns" of these different machiens off-road are almost bizzare sometimes.

for example, i once read one where several trucks were compared, and in part of the comparison they had to drive an H1 across a mud-pit, and then winch the rest through... but the H1 got 3rd or 6th or something in the "overall off-road score".

WTF? isn't off-road about making it through that mud pit?

Linus Gump -> RE: some H2 fast facts (5/29/2006 12:18:09 PM)

I know your info is correct, buecause I have done similar research in the past. The only question that comes to mind now, and when I did my own home work is; how does the Wrangler Rubicn claim to have a 10.3 inch ground clearance sitting on 31 inch tall tires, and the H3 shows a 9.1 inch clearance sitting on 33 inch tall tires? Ground clearance is measured from the ground to the lowest point on the vehicle. This is typically the differential or center section of an independant suspension. the Jeep uses Dana 44 axles, and the housings are the same size, if not slightly larger, then the ones under the H3. I measured my H3 and in the stock form, I actually had 9.5 inches under both the rear axle and under the IFS skidplate. From the center line to the bottem of the differential would be 7 inches based on the tire measurement of 33" since the tires and diff are on the same center line. If you apply the same math to the Jeep's numbers you get 5.2". 1.8" would be a significant difference since these numbers only reflect half of the diff. In the area of gears bigger means stronger. If memory serve, the D44 has a ring gear diameter of 8.8 and the H3 has a diameter of 7.5-8, and the housings hold a similar amount of fluid. If my ring gear is smaller, why would I have a larger case? Could it be that Jeep is measuring somewhere else to boast better numbers?

Greenblade -> RE: some H2 fast facts (5/29/2006 2:09:17 PM)


quote:

ORIGINAL: Linus Gump

I know your info is correct, buecause I have done similar research in the past. The only question that comes to mind now, and when I did my own home work is; how does the Wrangler Rubicn claim to have a 10.3 inch ground clearance sitting on 31 inch tall tires, and the H3 shows a 9.1 inch clearance sitting on 33 inch tall tires? Ground clearance is measured from the ground to the lowest point on the vehicle. This is typically the differential or center section of an independant suspension. the Jeep uses Dana 44 axles, and the housings are the same size, if not slightly larger, then the ones under the H3. I measured my H3 and in the stock form, I actually had 9.5 inches under both the rear axle and under the IFS skidplate. From the center line to the bottem of the differential would be 7 inches based on the tire measurement of 33" since the tires and diff are on the same center line. If you apply the same math to the Jeep's numbers you get 5.2". 1.8" would be a significant difference since these numbers only reflect half of the diff. In the area of gears bigger means stronger. If memory serve, the D44 has a ring gear diameter of 8.8 and the H3 has a diameter of 7.5-8, and the housings hold a similar amount of fluid. If my ring gear is smaller, why would I have a larger case? Could it be that Jeep is measuring somewhere else to boast better numbers?


yep.

clearance to the bottom of the Wrangler Rubicons (by my measure) differential is ~9 inches. maybe 9 1/4" considering the overhang on my ruler. Under the body clearance is just over 10 inches, and i think that's where they get their spec.

The H3 and H2 are indeed higher off the ground than the Rubicon, as you mentioned. The Land Rovers ground clearance is similarly optimistic, and you could measure much lower points than the spec'd clearance in any driving mode.


The attached pics are taken in a dealer lot under a Rubicon, one is the front axel/differential the ohter is the middle of the underbody.

Another perplexing thing about the underbody protection on the Rubicon is that it sort of tilts down at the front, making a "scoop" that seems like it would have some potential to dig into dirt over steep / sharp hill/bump tops like the ones i played around on a week or two ago.

Greenblade -> RE: some H2 fast facts (5/29/2006 2:32:24 PM)

i guess one other thing that might be relevant is crawl ratio.


Axels/suspensions
H1: 35:1 in older models and 45:1 in the H1 Alpha
H2: 33:1
Wrangler Rubicon: 65-69:1 depending on year, 73:1 in '07
Mercedes G class: 34:1*
H3: automatic: 56:1 , manual 69:1 (i think there might be 2 different available crawl speeds depending on options)
Range Rover: 35:1*
LR3: 46:1

* - taken from a review's graph. within +/- 1 or so


So the H2's crawl ratio isn't that great. i'm not sure what the significance of that is. The Lr3 and H3 & rubi have improved ratios relative to the rest of the otherwise similar pack.

Linus Gump -> RE: some H2 fast facts (5/29/2006 4:54:21 PM)

The H3 has two different crawl ratios because the Adventure package has a 4:1 low range, vs. the 2.64:1 in the base and Lux, and the differenc in 1st gear ratios of the automatic and manual trans, so actually there should be a total of four different ratios. The importance of these numbers is how much vehicle control you have when the going gets tough. The higher the number, the slower you can go over an obsticle without incurring vehicle damage.

Greenblade -> RE: some H2 fast facts (5/29/2006 5:20:28 PM)

is higher always "better" for crawl ratio, or are there times when it would be good to have a lower one? i can grasp some of the times that a higher one would be preferable...

if you had a higher craw ratio, like the H2, could you counter whatever up-side there might be to a lower crawl ratio by just allowing the tranny to shift into 2nd gear?


Linus Gump -> RE: some H2 fast facts (5/29/2006 6:24:19 PM)

Things like mud and snow require the tires to spin relatively fast to aid in self cleaning and for mobility. Think of it as reaction traction. For every pound of goo you sling backwards, one pound of vehicle is pushed forwards. A higher (numerically lower) ratio like what is in the H2 would be better for this, but it will require more power because of the loss of mechanical advantage given by the lower ratios. The other choice, if you have limited power, is to have an engine that has a very high RPM range to counter the speed reduction of the gear sets. Often the best choice off road is to select the low range in the transfer case, and a higher gear in the transmission. As a general rule in vehicles equipped with manual transmissions and low range ratios around 2.73:1, low range and 2nd or 3d gear is the approximate equivalent of high range and 1st gear. Automatics are geared different, so the rule of thumb is harder to apply, but 3d gear/low range seems to match close to 1st gear/hi range. Obviously with a manual in low range, you have better gearing selections, both faster and slower then if the transfer case was left in high. Over all, it comes down to the type of wheeling you do most. If you are a mud bug, you want huge power and higher gears. If you are a rock crawler, you want light power and low gears. If you are somwhere in between, like most people seem to be, something in the middle will work the best, but not be the best for the extreme ends.

Greenblade -> RE: some H2 fast facts (5/31/2006 8:05:01 AM)

hmmm... reaction-traction. i guess you'd have to toss quite a bit of mud to move an H2. [:o]

That was an interesting read, cool. How about for powering up steep hills? Does anybody get their jollies out of that? Outside of a big run at the hill, it seemed in my toying about that the H2 had a good combo for that.

I suppose low-gearing could drive an H3 or Wrangler up any hill, maybe just slower? What the heck is the limiting factor for hill climbing, anyway? Traction of course, but is the traction tire-based or does it come down to locked diffs and computer traction control and all of that? Center of gravity would play a role, i guess, ultimately limiting how steep you could go w/o tipping, or w/o mild tipping that lifts the front a bit? dang that would be steep. so its probably traction/power.


I think i'm getting a rough feel for how all of these different things - jeeps and hummers and differentials and wide and heavy and light - sort of interact. And i accept that its not raely possible to say "better" or "worse" except in obvious cases. A skinny little jeep can sneak through some narrow trail amongst the trees. A big wide hummer can rip down an open trail at far higher speeds & is less likely to do this: http://www.vintageoffroad.com/videos/hellsroll2.mpeg (watch til the end).

on a side note, an H2 breaks a tie rod when its tire slips off a rock and the truck lands with tie-rod-on-rock... and it finds its way to what? 100 places on the web?

some guy does that and nobody cares. you do have to admire the ability of the hummers to draw a crowd - real or figurative cyber


Linus Gump -> RE: some H2 fast facts (5/31/2006 11:46:09 AM)

You are getting the idea. For hills, the big thing is tipping over. If you have a low center of gravity, then it becomes more of a traction thing. The climbing numbers for the Hummers are for a vehicle properly loaded to max GVW in high range, and probably represents the steepest incline that you can maintain traction to climb, or the safest sideslope you can cross without rolling over. Somwhere amonst all of my junk I have the formulas to figure out where your center of gravity is on your vehicle for any loading configuration. Once you do that, it just becomes a matter of determining the maximum angle to keep the center of gravity within the wheelbase/track and you will know how steep of an angle you can climb/cross without rolling. Then all you have to do is worry about the traction aspect of it, and that can change from one day to the next, or from one run to the next.

Greenblade -> RE: some H2 fast facts (6/1/2006 11:20:29 PM)

that's interesting about the gross vehicle weight in high range. hi-open? that's very interesting. because the H2 can scale a steeper slope than its rating. i would suspect that for safeties sake the vehicles are rated quite conservatively.

a formula for calculating center of grav would be interesting. very interesting, i think i'll google for a spec on the H2 with respect to that - center of grav.

Greenblade -> RE: some H2 fast facts (6/1/2006 11:24:43 PM)

hey linus, i think the FJ Cruiser is another vehicle with over-stated clearance. almost 10" is the spec... but by my measure today its not as good as the hummers.

i'll zip over to the lot and take some pics as i did with the wrangler.

  

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