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Cherokee (KL) architecture discussion

Discussion in 'Rumors and General Chrysler Discussion' started by hotmach, May 7, 2020.

  1. LouJC

    LouJC Active Member

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    Actually anyone who knows Jeep history knows they’ve done this before! The XJ introduced in 1984 combined a stiff and light unibody with live axles and multi link coil front and rear leaf suspension; the Grand introduced in ‘92/93 added the rear coil multilink rear suspension for further refinement. When the TJ Wrangler came out a few years later it featured a suspension system nearly identical to the ZJ and WJ. The combination of the lighter unibody and live axles would work just fine and is far superior off road to the IFS and IRS used on the current Grands and smaller Jeeps because it has less travel and clearance. However live axles add unsprung weight and it is difficult if not impossible to make them ride and handle as well as independent suspension.
    Personally I’d live to see a full steel body Wrangler built on the Gladiator frame, with full 3 row seating and a large cargo area. THAT is what the Grand Wagoneer SHOULD HAVE BEEN!!!
    Think the original Grand Wag which has both more interior seating space and far more cargo space than any Grand Cherokee ever built....
    ps the Grand Wag SJ and the J10 Jeep pick up shared the same platform and many parts; a super size Wrangler based on the Gladiator frame would be a great product with none of the compromises of the modern Grand (cramped, too small cargo area, suspension inadequate for real off road use).
     
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  2. Dave Z

    Dave Z It's me, Dave
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    Original Wagoneer had an IFS option. Lil Blue has already been mentioned as an IFS Jeep (admittedly BOF) with far better off-road capability than CJ or Wrangler.
     
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  3. T_690

    T_690 Well-Known Member

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    Actually it's not platform related. More AWD system and powertrain choice.
     
  4. T_690

    T_690 Well-Known Member

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    But no IRS?

    Issue with IS is how to make aftermarket lift systems. That's one of the reasons why they never went along that route with Wrangler.
     
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  5. Dave Z

    Dave Z It's me, Dave
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    The head of FCA India would disagree with you.

    I think it was IRS too, I honestly don't remember.

    Bob said that aftermarket lift systems were not a consideration. For every dollar they made from people installing those, they lost a dollar on warranty and bad feelings from junk systems or poor installs blamed on Jeep.

    He described why they did not do IRS. I think it was a mistake, overall, but it worked out well either way. THe ideal, IMHO, would have been to do a Willys — to do both. A standard Wrangler for the ordinary person and a higher-end model (say, a Rubicon model) with the front and rear IRS for those who wanted an out-of-the-box ultra-stable off-road vehicle that could beat the best.
     
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  6. LouJC

    LouJC Active Member

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    Ifs or irs is limited in lifts by a few issues:
    CV joint angle
    In some cases the angle of the upper front ball joints can cause binding and aftermarket control arms are needed to correct the angles. These are common issues with lifts over 2” on the Grands with IFS...
     
  7. Zagnut27

    Zagnut27 Jeepaholic

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    As I recall Bob S was not a fan of lift kits...trinkets and trash I believe he said. Lil Blue had at least 12 inches of wheel travel without compromising the cv joints, could hit a curb at speed without tipping over, longer arm independent suspension. It was a really interesting design, though cost seemed to be the killer for why it wasn’t adopted.

    Here’s the Allpar article for anyone who wants to see/review again:

    Li’l Blue: the amazing independent-suspension Jeep Wrangler experiment (at https://www.allpar.com/SUVs/lil-blue.html )
     
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  8. freshforged

    freshforged Well-Known Member

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    Yes, I am aware. My concern is that live axles might not provide the on-road characteristics that TODAYS buyers expect. Everyone wants to have the comfort of a boulevard cruiser with the performance of a F1and the off-road chops of a mountain goat. Pick any two. And be prepared to pay.
     
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  9. CherokeeVision

    CherokeeVision Well-Known Member

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    Another balance to think about is weight balance. Nose heavy FWD and the handling characteristics that come with it aren't what I want in an off road capable vehicle.
    I would argue that having too much weight on the front reduces capability.
     
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  10. Dave Z

    Dave Z It's me, Dave
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    Audi begged to differ for years, and of course when the first American FWD performance cars came out in the 1980s, they simply trashed the old RWD models at the track (the Omni GLHS in particular). While that's not really a fair comparison, it does show that there's more to life than which wheels are driven.

    I will say putting the battery into the trunk is a good thing... though you pay for those long heavy copper leads.
     
  11. LouJC

    LouJC Active Member

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    It’s always what the car companies think they will make the most profit on. I know my idea for a Grand Wrangler probably will never get built but given what Toyota, Nissan and Mitsubishi sell in certain world markets, there is a world wide demand for such more practical and functional vehicles. The fact that Toyota, Nissan and Mitsubishi don’t sell theirs here though is telling. Apparently they don’t see adequate market here in the US yet these variants are often seen in South America, Africa and the Middle East. It would be nice if we had that as a choice though. Functionality vs overstuffed luxury.
     
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  12. CherokeeVision

    CherokeeVision Well-Known Member

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    Oddly, when I drive over uneven pavement heights at intersections, especially on turns I prefer the feel of my 01 XJ over our 09 Malibu. The firmer suspension seems to impart less head and body motion. Plus I will give due to the spring rate on the XJ which I know someone on Allpar stated played a huge part on the XJ not fatiguing the occupants.
     
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  13. Mopar392

    Mopar392 Well-Known Member

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    Ram 1500 comes with IS, and there are multiple lift kits and some of them for 4".

    I don't think there is a huge interest on lifting Unibody IS SUV.
     
  14. AC TC

    AC TC Well-Known Member

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    - it wasent needed anymore due to both better roads and better suspension tech. and it wasent as cheap as a standard setup and it did have parts that broke.
    But the case was against airsprings and adjustable suspension, here is the Citroen Hydractive way better and more robust.
    - another nice feature is that you can quickly move the wheigt load on the wheels, your front left is starting to climb a rock, its suspension softens to easy the uppward movement while you left rear stiffens to keep thing level..just an example.
     
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  15. MJAB

    MJAB Well-Known Member

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    It is not the architecture the reason the Renegade is "sub-Rubicon" capable.

    The Small architecture was changed to make it 4wd.
    500X project was not there. There was only the 500L.

    The reason why Renegade is sub-Rubicon capable it is because there is no reduction gear. It is all about gear ratio.
    Renegade has even a better breakover angle than most JL Wrangler... just to say...

    Just try to drive a Jeep Wrangler without activating the low range and go off-road uphill or on difficult obstacles that need very low speed.
     
    #55 MJAB, May 14, 2020
    Last edited: May 14, 2020
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  16. LouJC

    LouJC Active Member

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    true I have only seen a few lifted Jeep WK2s that have IS front and rear.
    However those who go to lifts that high will have problems with the things I mentioned, the inner CV joints will be at too steep an angle unless the differential is lowered; and the lift does change the angle of the upper ball joints and can put them in a bind, left uncorrected this can cause a catastrophic failure. These issues are the same with the coil over shock independent front suspension no matter whose it is; if you look at Jeep, Ram, GM, Ford, Toyota they are all basically the same design. Jeep’s live axle suspension is just superior off road and the complaints that people have with modern Wranglers are usually because of ill advised aftermarket lifts with extremely heavy and stiff “E” rated tires that are appropriate for a 6,000 lb 3/4 ton pick up not a 4500 lb Jeep. Look at Jeeps own Rubicon, approx a 2” lift, 32” “C” rated tires. Yet people think they “must” go up to 4” and 37” tires; then complain when it rides and handles like crap. Of course it does; they have completely upset the engineering built into the original design. Just because the aftermarket sells it and 4x4 magazines promote it doesn’t mean it’s good engineering!
     
  17. MJAB

    MJAB Well-Known Member

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    Off-road capabilities.
    One should ask what use I want do with the vehicle, where I want to go, on which tracks/roads/... I need to go, what I have (if I have to) to transport, how much I much use I will do of the vehicle off plain perfect tarmac and, but not least, how much I can spend to purchase and maintan the vehicle.

    What is off-road for You? Not for alls means rock crawling.
     
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  18. Dave Z

    Dave Z It's me, Dave
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    There is not enough articulation in the Fiat platform and architecture. There was even less in the original GM-Fiat platform.

    Renegade is not lacking in breakover angle; it's short. Length is the enemy of breakover. However, it is lacking in articulation.

    Look at the photos on Allpar of different vehicles going over the Chelsea offroad course. You will see that the Cherokee has much more extension of its wheels as it goes over obstacles. Wrangler keeps all four wheels on the ground, all the time. Cherokee sometimes goes up on two wheels, in extreme cases one wheel. Renegade looses a wheel far more often.

    If it was just a low gear, they would have put in a low gear.

    Again, look at Li'l Blue if you want to see an IRS design that can outperform a lifted JL.
     
  19. LouJC

    LouJC Active Member

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    The articulation is poor due to the short length and limited travel of stock control arms, which is by design because the standard CV design cannot tolerate more than a certain angle of operation. In fact this causes issues with lifts on modern Wranglers too because they use CV joints on both ends of the rear driveshaft and the rear end of the front driveshaft. The CVs have to be changed to high angle units with lifts over 2” or after market shafts built with double cardan joints. CVs are used due to lower vibration but they have their draw backs...
    lil blue used longer control arms to get better articulation but with lower unsprung weight than live axles.

    With our live axle Jeeps the only upgrades I’ve done are going to 30” tires and Bilstein high pressure monotube shocks. All we need for what we do...
     
  20. T_690

    T_690 Well-Known Member

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    GM? This is very insulting to Italians who had developed platform in question. That nonsense is repeated over and over again on this forum.

    Speaking about Renegade and off road. Me and mister @MJAB have right. AWD with reduction and more powerful engine would solve the thing. Or are you implying that 2.4 Cherokee with no reduction could pass Rubicon? The ball is in your half.
     

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