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The 2018 Jeep Wrangler JL status thread

Discussion in 'Mopar / FCA News' started by 12soldier, Aug 8, 2015.

  1. AutoTechnician

    AutoTechnician Well-Known Member

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    Your understanding of high/low pinion and reverse cut gears is incorrect. When you use a low-pinion different in a front axle, you "drive" using the "coast" side of the gears. The coast side is significantly weaker than the "drive" side of the gears. This is because a differential ring gear is not a simple bevel gear, but actually has an asymmetric tooth profile. One side provides more strength under power than the other.

    When you use a high pinion differential in the front, you "drive" on the "drive" side of the gears. A high pinion differential by nature requires a "reverse cut" ring & pinion, but that's not any weaker at all than a "standard" cut gear set.

    Basically, while going forward (reverse gear would be opposite for all of these):
    Low Pinion Diff in the Rear = Strong, power is applied to the "drive" side of the gears
    Low Pinion Diff in the Front = Weak, power is applied to the "coast" side of the gears
    High Pinion Diff in the Front = Strong, power is applied to the "drive" side of the gears
    High Pinion Diff in the Rear = Weak, power is applied to the "coast" side of the gears

    There is nothing inherently weaker about a high pinion reverse cut gearset, but it will be weaker if used in a rear axle application, just like how a low pinion is weaker when used in a front axle application.
     
  2. Dr. Jeep

    Dr. Jeep Well-Known Member

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    Yes, thank you, you are correct, thanks for correcting my phrasing and terminology. However, the original point stands, any driveshaft issues in the JL could be further corrected by the use of a high pinion rear centersection, but the gearset is going to need some changes to handle the requirements of the vehicle.
     
  3. Rick Anderson

    Rick Anderson Well-Known Member

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    If you have a reverse cut gear set, wouldn't you be switching the drive and coast side of the gears?

    I don't know if this is correct, BUT, this is what I envision as I think about it.
    Low Pinion Diff in the Rear = Strong, the pinion pushes the ring gear away from it to rotate it in the direction to move forward.
    Low Pinion Diff in the Front = Weak, the pinion pulls the ring gear toward it to rotate it in the direction to move forward.
    High Pinion Diff in the Front = Strong, the pinion pushes the ring gear away from it to rotate it in the direction to move forward.
    High Pinion Diff in the Rear = Weak, the pinion pulls the ring gear toward it to rotate it in the direction to move forward.

    In Reverse, the pinion and ring gear swap to the reverse dynamic, whether that be going from push to pulling or contacting drive side to coast side.
    Which you've already confirmed, so I know I've got that point right at least.
    And a front axle is just a rear axle turned around and running in reverse, so a high pinion in the front would be the same as low pinion in the rear.
    That is obvious from what you've posted.

    What I'm kinda stumped on, if you reverse cut the gear set, why isn't the coast and drive sides of teeth reversed, thus a high pinion in a rear axle would be contacting the drive side of the teeth. The thing that jumps out at me, as you look at how the gear set rotates, a high pinion in the rear axle (or low pinion in a front axle), the pinion would be pulling the ring toward it, while a low pinion in the rear axle (or a high pinion in the front axle), the pinion would be pushing the ring away from it.
     
  4. andognam

    andognam Member

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    When and where the JL will be presented to the public for the first time ?
     
  5. link3721

    link3721 Yes, This MK Goes Off-Road

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    I would hazard a guess of summer 2017 at an off-road playground.
     
  6. 12soldier

    12soldier Well-Known Member

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    Maybe a place where they receive a "trail rated" badge??
     
  7. Muther

    Muther Well-Known Member

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    It would be intro'd in NY, if it was to be at a show. Most likely, I'd say at the Easter Jeep Safari, Jeep has really made that the place they go to show stuff off.
     
    xjgary likes this.
  8. Ruptured Duck

    Ruptured Duck Active Member

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  9. crmarczak

    crmarczak Active Member

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    As someone who runs with the soft top 12 months a year, and the rear and side panels off 9 months a year this top discussion is interesting. Any time I get around 2-3 nice days in a row I've got the top down and the doors put in my rear seat. Now since I run pretty much open all I need to do is unclasp the two hooks by my visors, pop out the plastic lips from above the doors, then fold it down. Probably takes 30 seconds. Putting it up though can be much more annoying, the 10 year old fabric does not like to be re-clasped without being very hot and stretchy, or without my undoing of a rear corner clip.

    I have no problem doing this, I've got a handle on it over the years and I don't mind the mess. That being said it can be a hassle as here in New England it tends to get gold quickly and the fabric becomes less malleable at that point. I could very easily see a little sallie sue not undoing the top because it could be a pita to her. So I guess I am very interested to see how this rumored automated top might function should it be a thing.
     
  10. valiant67

    valiant67 ...

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    Here's what I hate about the soft top - having to unzip that stupid window to put anything larger in the back (and it happens a lot for me). Plus the flapping of the windows drove the dog crazy.
    Here's what I hate about the hard top - it's more time consuming to remove the front panels than to fold the softtop back partway. And you can't open the rear or side windows for additional breeze.

    But I've been happier with the hard top than the soft top.
     
  11. JKU12

    JKU12 Well-Known Member

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    I've always found the soft tops to be a pain the butt. Zipping the windows in and out, trying to keep them scratch free when not in use, in cold weather finding the material really hard to stretch, etc. Therefore I tend to run hardtop in winter and if I take it off for summer, run with no top on, except for spiderwebshade.

    Any redesign of the soft top to make it easier to go up and down on a more regular basis would be a much needed welcome from my perspective. As it is now, you have to leave the house with a particular configuration and it's hard to adjust on the fly. This doesn't work well when a Wrangler is used the way it's supposed to be used - ie for outdoors adventures over multiple days
     
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  12. Rick Anderson

    Rick Anderson Well-Known Member

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    The 2nd hand report of seeing a JL at a Dealer Preview, said it was a soft top and a cooperate person on hand said it would be easier to get up and down.... ...again take it with a grain of salt...

    But, to me when I hear that, think integrate roof, sucked in to fit a soft or hard top over it, so that the soft/hard top fits flush with the body. Likely very open and shaped to support soft top fully at all points. i.e. no more bows and rods with plastic pivots that break, to make a supporting structure over the sport bar that has no support for the soft top in some places. It would be like pulling a tarp taught over a box and snapping it down.

    Again, this was a 2nd hand recounting of a preview with the 1st hand person NOT mechanically inclined enough to really understand what she was looking at.... .....so hardly a confirmation of what it will actually be.
     
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  13. Ruptured Duck

    Ruptured Duck Active Member

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    The older JJ concept may be what a lot of people are expecting. This has been noted several times and Bob had noted this as well.
    jj.gif

    Still holding out based off some patents filed.

    soft top patent png.gif
     
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  14. AdminDave

    Staff Member

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    which is rather similar to the Fiat 500C... but with more cross bracing.

    That would allow a LOT of weight loss for the Wrangler so it's not all bad.
     
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  15. Rick Anderson

    Rick Anderson Well-Known Member

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    I look at the patent drawings, and that looks nearly as open as the sport bar, a different looking sport bar even. More cross bracing then a Fiat 500 likely because its more open than a Fiat 500.
     
  16. Ruptured Duck

    Ruptured Duck Active Member

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    This patent is for a garage door type lowing of the soft top. Only shows 2dr version. You would still need to remove the side windows to allow it to work if I'm looking and reading it correctly. It still has a spring assist (currently not available on 2dr versions) to aid in the up and down movement. This design helps to keep everything in alignment as (ONE) person operates. Now it could possible have a powered option like a cabled sunroof movement but the side windows would have to be removed for it to work correctly. There have been two aftermarket power tops offered for the JK 4dr.

    Hope the moderators will allow the videos to stay. It looks like advertising but I'm not promoting either one. The Rugged Ridge version is no longer offered.

    Rugged Ridge made one... NOTE IT IS NO LONGER ON THE MARKET AND NOT BEING SOLD

    It was a very expensive item and had engineering challenges but did keep the side windows in place. It used two hydraulic rams like most systems have.
    MyTop currently still offers a power top

    It is also rather expensive as well. It uses a gear driven system rather than hydraulics.
    Both tops tried to deal with the side windows as best as possible. The Rugged Ridge top folded almost as far down as the factory top. The MyTop did not sit down quite as far and made your rear view mirror useless.

    The biggest challenge for both designs was getting the bows to move past the sport bar as they are lowered. The Jeep is tapered front to back so the front of the tops (Header) needed to get wider as the moved backwards. This is something Jeep would not have to worry about if they were to start from scratch.
     
    #1256 Ruptured Duck, Jun 9, 2016
    Last edited: Jun 9, 2016
    Mike V. likes this.
  17. Dave Z

    Dave Z It's me, Dave
    Staff Member Level III Supporter

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    It's bigger, heavier, has a rougher life, and most likely the 500 relies on the convertible exemption.
     
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  18. MJAB

    MJAB Well-Known Member

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    In a structure like the one used for the Fiat 500C can be installed the side curtain airbags (that Fiat 500C have) that are useful for ejection mitigation from lateral windows.
     
  19. WXman

    WXman Active Member

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    That's been my guess. I'm betting that they bring one to Easter Jeep Safari next year. If they do, the media will be all over it like a soup sandwich.
     
  20. Rick Anderson

    Rick Anderson Well-Known Member

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    That is consistent with the different things we've heard so far. There would removable panels, you'll like the new roof, something like the Liberty SkyRoof, etc, etc....

    The roof will integrated, steel stampings, spot welded together to form somewhat resembling tubes with some bracing, to be open and look somewhat like the old sport bar.

    The soft top will be only the roof and rear window, it does NOT extend down or around the sides. It will easily retract all the way back and down behind the rear seats. The side windows will be pop out panels you can stow between the retracted roof and the rear seats.
     

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