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  1. #1

    Gears.....Axles.....Drive Shafts....Etc

    Hey Everyone!

    Here is the Gear thread! Tell us about your set up and how you like it.

  2. #2
    1st set up Ive driven with

    2012 Jeep JKUR Pentastar
    4.10 gears
    305/75R17 tires Duratrac Goodyear 34.4"

    This is stock everything, but tires. How do the 4.10s deal with the larger tires? Just fine. I think that the truck was OVERGEARED from the factory. It felt more natural on the highway with the 4.10s and the larger tires. I could cruise at 75 mph where before i would have to keep in a higher zone of the RPM band to maintain that speed.

    Overall Thoughts- This was a gearing improvement, raising the tire size with the stock 4.10 gears.

    Click image for larger version. 

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  3. #3
    Senior Member
    Join Date
    Feb 2014
    MD/PA line
    My stock rubicon 6 speed with 4.10 gears was a bit too jumpy off the line. The front end would pop straight up in the air, even under light acceleration. I'm sure it was a combination of suspension, gearing, and the fact that it was a manual trans that caused it. Point is, I could see myself with the exact same vehicle on lightweight 33-34"s without having to re-gear.

    37s, body armor, huge rear bumper and tire carrier, winch...I'm thinking a re-gear is necessary without having the additional power you have with boost. But its all just opinion really when it comes to drive-ability and how each person feels about revving it up before shifting, etc. And its magnified with the automatic need to re-gear sooner based on what I've read, and/or gear a bit higher in the axle to achieve the same "feel" the average person likes.

    Personally, I'm doing Yukon 4.88s with the factory E-locker with 37" km2s. Driveshafts will become important. For now, a teraflex exhaust spacer will work to keep the front shaft's boot off the exhaust.

  4. #4
    Betty's Current Set-Up

    4.10s with 37s

    3.6 Pentastar....Supercharged.

    Ok so can the standard 3.6 pentastar turn 37s well with 4.10s? I really dont know. Betty was supercharged before the 37s got installed. How did the Supercharged Pentastar do? Just fine. I've had 4.88s in the house for over a year now. I've felt no reason to install them as the truck is a dream on the highway as its geared right now.

    She cruises at 90 mph with no problem. Thats the best part. 7 hour road trip? No problem. Black Betty is the truck of choice because of her power and gear set up. She comfortably eats hundreds of miles at a time.

    I think its easy to run long road trips in with BB because she cruises so fast, you always feel like your making good time. So psychologically, she keeps the driver in a good mood. I'd get depressed plodding along getting passed every few seconds.

    The only downside to this set up is that the police are a serious concern. You can easily forget how fast your going.

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  5. #5
    We are going to change Betty to 4.88s later this month for a more aggressive trail set up. I'll let you know if I like it less.

    Here is all the Yukon Gear we are going to install.

    Its their chromoly axle shafts and 4.88 gearing. Its all the complete axle seal set up.

    Got it all from randy's so its all from the same manufacturer and should all fit together perfectly.

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  6. #6
    Senior Member
    Join Date
    Feb 2014
    MD/PA line
    MAN, I'm super jealous! You're going all the way with chromolly shafts too? I just did a ring/pinion change. It won't be as strong as yours after you're done, but I figured I'd replace one when it busts. Maybe I should have done it when i swapped mine out. I just wasn't thinking that far ahead. I went with yukon too, everyone seems to think they are good for the price and my local shop said it is their preferred setup.

    With the increased weight of the 37s, I think the gear change was essential. I feel that pulling out in 1st with the 4.10s would have required a bit of feathering while revving the engine more than I'd like. That means more clutch wear and I wanted to avoid that.

    Having not driven on the 4.10s with 37s, it is difficult to make a direct comparison. The shop had the axles apart to do the Artec truss setup and when he put it back together he threw in the 4.88s. Pulling out with the 4.88s feels about like the stock 4.10s felt and I didn't mind how low it was geared so it works for me.

    Highway driving is perfectly acceptable with the new setup. I haven't re-calibrated my speedometer yet for the new gears/tires, so I can't provide the RPMs at a given speed. But when I get that fixed, I'll know where I'm at and can share.
    Last edited by Snarf77; 03-09-2014 at 07:35 PM.

  7. #7
    I have a 2012 JKUR 6-speed also, and I loved the stock gearing with the rubicon tires in the mountains. My jeep would pull itself around in 4hi like it was in throttle needed unless I was in a really steep area. Now that I'm on 35s, I'm dying for a regear. I will install 5.13s from yukon, with chromoly axle shafts, and Tom woods rear drive shafts. Should be very interesting with the magnuson...called them yesterday about a purchase, so this may all be happening sooner than expected.

  8. #8
    My dad's is a 13 jku sport auto with an AEV budget boost,285x70xr17, and a ripp supercharger(gen2 tune). With the new tire dad dropped 4.56 gears in. In all honesty the gears made a bigger"knock you back in your seat difference" than the ripp did. My dad only drives the highway maybe once a month for a very short distance. He wanted his jeep to accelerate like a performance vehicle and still be a capable off roader and daily driver. That's exactly what he got, and surprisingly enough his <45 mpg increased. It also helped get the jk into the higher areas of the rpm band so the ripp kicks in sooner after you mash the skinny pedal, instead of the normal wait.
    Attached Thumbnails Attached Thumbnails image.jpg  

  9. #9
    With the ripp and stock 3.73s on stock rubi tires the 0-60 was 7.94

  10. #10
    Quote Originally Posted by Deola View Post
    With the ripp and stock 3.73s on stock rubi tires the 0-60 was 7.94
    Is that an auto? stock tires?

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