6 pages on this!! wow.

07-11 on 35s go with 4:88
12 on 35's go 4:56.

 

Yes, it's an auto. Gearing principles apply to both.

Of course. There are many variables involved, even between same transmissions.

I don't need to justify that, because I didn't feel a huge loss of power after bigger tires. Regearing was kind of silly for such small power loss. All I'm trying to say is that there are alternatives to regearing, with its own pros and cons.

I don't drive fast on highway, I try to keep to 60-63mph, always use cruise control. This mileage was hand calculated during 4-5 runs between Seattle-Bellingham I did recently. My city mileage however sucks big time. I was in 14's on stock tires, now in the 12's.

True, that heavier loads, tires, impact the entire drivetrain, not just the transmission. However, lower diff gearing only aids the transmission if transmission is in a gear that's too high. If diff gearing is too high, then transmission should be in a lower gear. The output gear ratio to the wheels will be the same or close. I don't know how many more times this needs to be repeated to get the point across?!

Think of a bicycle, you have gears in front at your crank arms (pedals), and in the rear at your axle. If your rear gear is too high, you simply select a lower gear in the front. If rear gear is too low, you select a higher gear in the front. The output gear ratio to the rear wheel will be the same or very close, depending on how much you can fine tune your output gear ratio. They are not independent of each other, and work as a system. The load on your legs will be the same regardless of how you shuffle your front and rear gear sets, as long as you can come up with an efficient/optimal output gear ratio.

In a vehicle when you have a heavy load behind you, or are simply climbing a steep grade, or cruising on flat roads, the gearing works the same way. Let's say you have 4.88 diff gears, in 5th gear manual (1:1 gear ratio), and the engine produces a theoretical 100 ft-lbs of torque. This means you'll be putting 488 ft-lbs of torque to your rear wheels (let's say it's just enough to happily move the vehicle). Now if you had 3.73 diff gears, that would put only 373 ft-lbs of torque to the rear wheels, and you might find that the engine started to work a bit too hard to move the vehicle (engine load increases). So you'd have to lower your transmission gear to add more torque to the wheels. You go down to 4th gear (1.25:1 gear ratio), and now you got 466 ft-lbs of torque at the wheels. Your wheels don't care how this additional torque got generated (through lower diff gears, or lower transmission gears, or perhaps a lower transfer case gear, or maybe even a turbo). All that your drivetrain cares at this point is whether or not it can handle all the torque going through it. Axle shafts will need to be the strongest, as they get to handle the most torque. All that transmission cares about at this point is whether or not it can handle the engine torque input, which did not change between 3.73/4th gear and 4.88/5th gear ratios, and stayed at a constant 100 ft-lbs.

 

This is getting heated hahhaahha.

I am goin to regear. It's just a matter or when and if I have convinced myself to run 4.88 or 4.56

 

I know about as much as you do about this Jeepwave, and from all the comments so far I've chosen 4,56 for on-road drivability and also in case i ever end up with smaller tires. Sounds like 4.88 boxes you in as an offroad machine.

 

I wouldn't say that 4.88s make it an off road machine. 4.56s will give you a great on-road vehicle with good off-road performance. 4.88s will give you a great off-road vehicle with good on-road performance. So you just have to make the call which is more important to you. Also if you have 37" tires in your future that would play into the decision as well.

To help make the decision easier, a 6 speed rig with 4.56s and 35" tires has almost exactly the same overall gear ratio as a stock 6 speed Rubicon (3.8 liter). So if you have driven a stock 6 speed Rubicon or you can drive a 6 speed Rubicon that will give you an excellent idea of what 4.56s would feel like. 4.88s will shorten each gear up a bit and at highway speed be a couple hundred RPM higher.

I hope that helps!

 

This may be a really stupid question but I'm up to be laughed at :/... Would a super chips change this at all? Or is that basically only changing shift points in an auto?

 

If you're looking for performance gains out of a superchips, don't waste your money on it as it does nothing. Even if you would get extra 5hp out of it, you would never notice a difference. There is a reason they don't provide a dyno sheet to compare performance gains. It does have, however, some other features that may or may not be useful to someone, but power gains isn't one of them.

 

Good grief, man !!! You just ooze with foolishness !!! A good chunk of this thread are these absurd comments you make that go against just about everything known to mankind !!! You're not even addressing the question that jeepwave asked !!! You just oozed more foolishness out and its getting all over my computer screen !!! It's so absurd, I can't stop using the exclamation point !!!

For the love of Jeeps, please educate yourself with some simple searching on this forum and on Google !!! Within 3 minutes (yes, I timed myself), I found the following links:

The Official Superchips Forum • View topic - HP and MPG gains for a 2007 Jeep 3.8

https://www.jk-forum.com/forums/modi...essions-80188/

Jeep Wrangler JK Tuner Shootout - Jp Magazine

@ jeepwave, I don't have the answer to your question, but I think it's a great question and I hope someone other than TheTerminator can give an intelligent answer or share their personal experience. Personally, I also would like to better understand how a tuner helps with a regear.

 

I just have to say that this has been a great thread! But this comment just made my morning!

Thanks for that man! You said with 100% accuracy, exactly where my thoughts were going as I read each back and forth comment, page after page. I got to your comment and just errupted with laughter!

I really doubt the OP expected a Jeepocalypse to unfold over such a simple, yet probably, very often asked question!

To TheTerminator, I'm with ya bro, sometimes it's hard to give up the fight.

With that said, I'm going to have to side with the common sense, common knowledge, factually, and technically sound majority on this thread and say that the OP could see and feel benefits with a regearing. It was suggested to the OP to stay in the 4.56 to 4.88 range to maintain some level of DD ability while improving the off roading ability and I totally agree.

 

I think the terminator drives a Hummer H3!!!!!!