A few good points there rwinch, however:
1. The comparison is merely to illustrate that not "all" competent off road vehicles need to have a solid axle. Secondly there are aspects of the IS on the H1 and the Expedition ('03-+) that are similar. The differentials, both front and rear, do not hang down in the center of the drive path, which allows for greater ground clearance under the center of the vehicle. The drive shafts are articulated through the frame rails, although on the H1 they have dual articulations w/ gearing to transfer more torque and power.
2. Internationals rock... of course they do, and of course i am aware that they have solid axles. I have never said anything denegrating about solid axle vehicles. I happen to own an '01 Excursion Limited 7.3 PSD 4x4.
3. "Serious offroaders".... not sure who that really refers to. Is there a certain number of hours one should obtain to become certified... but you are correct, most of the rigs which people use regularly off-road have solid/live axles, but i think that is due to a lack of availabilty of IS vehicles. Greater articulation for solid axles... not really sure why that would be the case. Usually the limiting factors in articulation have to do with wheel well clearance (thus lift.. which i will get to shortly), frame clearance and suspension compononent clearance. In fact, solid axles limit their own articulations by being solid. the higher one wheel goes, the lower the other, and eventually the vehicle will roll. The wheel which maintains contact with the ground will be slowly lifted of the center tread onto the edge of the tread and eventually the sidewall. Even with a limited slip differential (which in my opinion should be standard equipment on every vehicle made, not just trucks or off-roaders), you begin to lose tread contact and thus traction. This situation does not occur with IS. Of course both vehicles willl evetually roll if pushed too far. Now you say that more power is transmitted through solid axles. In theory you may be correct, but if that power is not effectively transferred to the wheels because of loss of traction, then is it relly more power transfer (e.g. washboard roads where solid axles skip and hop, losing traction, as well as in the situations with the articulation issues previously mentioned, dips/holes or rutts where the one wheel drops, end up lifting the other wheel off the road with a solid axle even if it is ever so slightly). Let's see... "easier to lift...and you can put more shocks on..." Do you mean that there are more kits available for the solid axle vehicles? Because there are kits available for the ('03-+). It can easily be lifted up 6". As far as more shocks.. I think you will find that that is mostly for show. A good, well-valved, single chamber single shock is all that anyone needs, especially at slow speeds going over big rocks and such. Multiple shocks will inhibit articulation and spring action. You are right about the springs on the '98 Expedition, the front springs anyway. Are you sure the rear springs on the '98 Expedition 4x4 are coils? I am pretty sure they are leafs on the rear. Let me know. Oh yeah and the durability issues of solid axles compared to IS. You are of course referring to the solid metal casing around the solid axles whic the IS axles do not need because they, like their differentials are neatly tucked up and away.
Next, here is something to consider: the factory 4x4 Expeditions '98-'02 all sit (are lifted) approximately 4" higher of the ground than the 4x2 models of the same year. The factory 4x4 Expeditions from '03-+ sit at the same level as their 4x2 counterparts. The 4x4 '03's and newer are not "lifted" from the factory. So in order to make a fair comparison perhaps one might want to lift the '03 4" and then try to knock its off-road performance compared to the '98-'02's. Point of fact: All Expeditions rock! If you have a '98 KEEP IT! If you want a new one GET IT! I do not think that there are any vast differences in these very capable vehicles. These vehicles are not "the choice", however when it comes to what i think rwinch is referring to as "serious offroading" such as bouldering or muddin'. If you want a "serious offroading" vehicle try something lighter with a shorter wheelbase (and a winch). The other issue is going to be the driver. The skill of the driver will make more difference than which year your Expedition is. There are reasons why Ford did not lift the '03-+ 4x4 Expeditions(i wish they had), many of which i do not know i'm sure. Probably C of G (center of gravity), one of the things which can also be important off-road. The reason I can take my audi and my subaru places where you guys can not go in your trucks is because i can traverse a 42 degree slope and because i can ascend even steeper. Low C of G. Which also provides for better power transfer. The higher your vehicle is lifted, the worse the power transfer. Anyone who lifts their truck more than 6" over stock has a serious Napoleonic Complex. The same goes for multiple shocks. These things are just for show and do not improve off-road performance. Take one of those trucks with a 12" lift and 40" tires out in the mountains to follow me and he will end up in the bottom of a gorge because the slopes are too steep for that high a C of G. A lift and bigger tires are nice and can enhance performance off-road to an extent. I plan on lifting my '04 4x4 Expedition XLT Sport 4" and putting 33" tires on her. She should then be able to go anywhere a mechanized vehicle should. If i encounter a field of 6' boulders or a mud bogg 6' deep, i will drive around it (off-road all the while), or i will get out and go for a hike (which is the main reason i go off roading anyway).
Happy Trails,
Exsport
