Solid axle SUV

[tjkj2002]

Ditto.........and they won't fit anywhere off road around here unless you run a dozer before it.

I never understood why they wern't made with a SFA.......

Dave

Not so,I have been places where a well built TJ would have a very hard time getting to in a run of the mill goverment HMMWV.There hauling capicity(up to 10,000lbs) and being able to go in those same places is unreal.In Afganistan my contact truck(a HMMWV with a portable tool shop) would put to shame most mod'ed wheelers,even at a curb wieght sitting around 15,000-16,000lbs.Tranversing 60 degree+ climbs and desends,2+ feet of mud,and high speed travel on very rough terrian.And as for being harder to repair,FALSE,just a different way is needed,not harder just different compared to a SFA vehicle.In the case of the HMMWV everything about the suspension and driveline is simple and easy,heck changing a CV shaft takes about 10 mins max,and the fact with 18" of ground clearance there is rarely a need to jack the vehicle up except to take a wheel/tire off.

Now I'm all about SFA,doing the coversion on my KJ,but a well built IFS/IRS setup can be just as good if not better.It's all about the $$$$.


Oh and the HMMWV and cilvian H1's all run aluminum diffs also.

 

[Ry' N Jen]

Not so,I have been places where a well built TJ would have a very hard time getting to in a run of the mill goverment HMMWV.There hauling capicity(up to 10,000lbs) and being able to go in those same places is unreal.In Afganistan my contact truck(a HMMWV with a portable tool shop) would put to shame most mod'ed wheelers,even at a curb wieght sitting around 15,000-16,000lbs.Tranversing 60 degree+ climbs and desends,2+ feet of mud,and high speed travel on very rough terrian.And as for being harder to repair,FALSE,just a different way is needed,not harder just different compared to a SFA vehicle.In the case of the HMMWV everything about the suspension and driveline is simple and easy,heck changing a CV shaft takes about 10 mins max,and the fact with 18" of ground clearance there is rarely a need to jack the vehicle up except to take a wheel/tire off.

Now I'm all about SFA,doing the coversion on my KJ,but a well built IFS/IRS setup can be just as good if not better.It's all about the $$$$.


Oh and the HMMWV and cilvian H1's all run aluminum diffs also.

Point made!

 

[Marlon_JB2]

but a well built IFS/IRS setup can be just as good if not better.It's all about the $$$$.

Exactly my point.

What the Liberty could have been (Bob Sheaves)
I am one of those rabid Jeep fans that hates the KJ, for what it is. There was an opportunity to showcase a good independent front suspension (IFS) and the management blew it. If you remember back before it was introduced, I was a supporter of the car, because I knew what Chrysler had on the shelf (from the "King Of The Hill" prototype) and didn't think the management ignorant enough to NOT use it. Unfortunately, I was wrong and the "little girl's car" that debuted was a mess. All it would have cost was another $70 per vehicle (yes, that's a lot, but IMHO, the cost was justified-you don't see new HMMWV's running around under $100K today and the KJ could have had that much mobility).

The one bright spot for me is the Rescue show car-I know from my work on the Dodge Ram 4 link over constrained system, that this vehicle is (again, for me only-I am not telling anyone their ideas are wrong) a ray of hope and lust (amazing what yanks my crank, ain't it?) because of the air springs, long travel, AAM axles, and the possibility of an inexpensive (relatively speaking, of course-for home installation) of a CTIS system. All of this wrapped in a basic (meaning simple construction) body that is free of frilly plastic and junk (obviously, I am discounting the wannabe lamps built into the roof rack-another useless affectation from Design Office).

What many off roaders forget (or never knew) is that Jeep, in 1962, invented the first independent front suspension (IFS) for an off road vehicle in the US [Wagoneer] and offered it as an option.

The suspension Evan Boberg talks about in his book started out as the 1962 Wagoneer suspension-that was the genesis of the improvements...

My disgust with the KJ comes from the half-hearted job done on the IFS. Personally, I don't care what suspension is used, as long as it performs to the intended goals and parameters. In this respect, I have to admit the KJ does well-it was designed as a "girl's Jeep"...people may not like this characterization, but nontheless, it is quite accurate in describing the performance parameters. Jeep had, on the shelf, a design that would make the currect suspension seem as antiquated as the hotchkiss used on the CJ's, when looked from a technical standpoint. Unfortunately, there are only about 20 people in toto that have driven this kind of suspension, and 4 of them are NOT from Chrysler (I built a more advanced version of the KOTH Jeep suspension for a friend of mine under a Chevy full size Blazer (the GMT 400) that had 18" of wheel travel and a stock track width).

Unfortunately also, people that are not suspension engineers tend to be a bit ignorant about the pros and cons of variuous designs, hence the fear (justified in some cases) that the Jeeps will be "screwed up". by people (meaning the design and engineering staff of the controlling company) that have no idea what a Jeep is. These types of people generally cling to some perverse idea that change is bad-I agree with you on the statement, but not the reasoning there. What people need to understand is the the word Jeep, since it's inception, has ONLY meant one thing and one word....

MOBILITY

The history of Jeep has never been centered aroung "change" but rather using the most defined parameters (it started with the military as "everyone knows"- but I would bet any amount of money that not 1 in 10 "experts" can list even 5 of the original military mobility requirements. Jeep has always been a purpose built vehicle-it has ALWAYS hit the intended target. That is not to infer that the targets were acceptable to the marketplace (the FC's and the KJ are 2 different examples of bad targets that were hit and while one failed, the other has been prosperous). Until a good independent suspension is manufactured in the general marketplace and people try it....change will always be viewed as bad.....

Actually, it predates the Kinetic system, which is marketed by Tenneco Automotive now.

The suspension I am describing is one that, in addition to allowing the left and right tire to move independently of each other, allows the axle to move vertically as a percentage of the total wheel travel, the point is to allow the CV joints to be used for turning and power transmission without exceeding the limits of travel. What Evan described in the book (meaning comparing the HMMWV IFS/IRS to a Jeep Link/coil) demonstrates the limits of Rzeppa and tripod joint construction. This all means that a conventional IFS is limited to 8" of vertical travel, in general with a fixed axle, as used on the KJ. With the "floating axle" design this can easilly increase to 12" and more, IF the length of the control arms is optimized.

You can search the US Patent office for "Evan Boberg" and call up the patent and drawings for this design to get an idea how it works.

 

[icarl]

Exactly my point...

I wonder when this was said. It would be interesting to hear what he says about the 2008 liberty IFS to see if he thinks it is any better. I heard the diff was supposed to be stronger.

 

[Marlon_JB2]

I wonder when this was said. It would be interesting to hear what he says about the 2008 liberty IFS to see if he thinks it is any better. I heard the diff was supposed to be stronger.

Have you seen the 2008 Liberty IFS?

For a sneak peek, look under your KJ.

Sure, a few changes have been made. it's not 100% identical, but 90% ain't much of a change.

Bob still isn't happy.

 

[J-Thompson]

Ya'll can say what you want
bottom line if you can not keep the wheels on the ground then you MUST have a locker
most ,not all, IFS rigs do not even have a locker option thus they will not be even close to a TJ with out a locker as the wheels will stay on the ground in a TJ long after the IFS rig gets a wheel up
I did not use a JK because the traction control gives it a leg up over the TJ

Off road is all about traction
on road it is all about comfort
99% of people buying SUV's would give up traction to get comfort
now if you want both you need to buy comfort from the dealer
and add traction your self but you will still reach your limit long before an SFA rig with the same mods
you add a locker he adds a locker
you add 3" of lift he adds 3" of lift
ect.

 

[Dave]

Marlon....did you get the Bob Sheaves posting off the ALLPAR website??

I have read that before but can't remember where. It is good.

Dave

 

[tjkj2002]

Off road is all about traction
on road it is all about comfort
99% of people buying SUV's would give up traction to get comfort
now if you want both you need to buy comfort from the dealer
and add traction your self but you will still reach your limit long before an SFA rig with the same mods

You haven't driven offroad some of the higher end IFS/IRS rigs have you?(and not the luxury kind either)

A H1 is bone jaring even on smooth pavement.You gotta pay to play,there are custom CV's that have been tested in the Baja1000 in 1000HP trucks and never failed,no boots and no grease either($50,000 a pop though).

Yes SFA is cheaper but not really any better.You add lockers to a SFA vehicle so adding lockers in a IFS/IRS vehicle is no different.



I have offroaded both SFA/SRA and IFS/IRS vehicles and they are about equal.the KJ is the exception so hear comes the SFA to match the SRA,cheaper then a correct IFS/IRS setup.

 

[o8k]

good thread, talk it out

my 2 cents

1. yes the kj is an SUV sorry, it is... get over it... (i can get you a got groceries sticker when your willing to come to terms w/ this, hehehe)
2. there is no "right way" to do IFS and SRA (IMHO), cept start over and do all independent or all solid axle.
3. remember humer 1 is independent all round but there are geared hubs where the wheels attach so the axles dont come in at the center of the wheel, but up higher, thus getting the A arms up and out of the way too
4. my kj libery owns joo, bish! (well not joo all, but ya know...)

 

[Marlon_JB2]

Marlon....did you get the Bob Sheaves posting off the ALLPAR website??

I have read that before but can't remember where. It is good.

Dave

Yup.

 

[Ry' N Jen]

3. remember hummer 1 is independent all round but there are geared hubs where the wheels attach so the axles dint come in at the center of the wheel, but up higher, thus getting the A arms up and out of the way too


Thanks to Mercedes Benz.
So much for American ingenuity.

 

[kj lad]

Solid axles are preferable in most cases because the engineering is much simpler so in theory should be more robust.

I get the impression that most of you consider rock crawling the only serious offroading that a 4x4 can do. That's not so. In practice most offroading involves every surface! Rocks are just a small part of it.

IFS in theory should generate more traction as the tyre should stand flat on the ground where as a solid axle will make the wheels travel on their edges in high flex situations.

I suggest that solid axles are more reliable that is why the first vehicle over 2/3 of the African population saw was a landrover defender. Until the TD5 emgine was fitted it was hands down the most rugged and reliable offroader. However the Toyota landcruisers and Nissan Patrols are now probably the best expedition vehicles. Expedition vehicles are (in my opinion) the best indication of the capabilities of a proper offroad or cross country vehicle as they combine ability, ruggedness and reliability.

Just my pennies worth!

Ian