Quote:
Originally Posted by JacksXJ
with 3.07 gears and 31's and can cruz at 70mph reving at 2000rpms in 5th gear

No you aren't, fix your speedometer lol

Verified the speed with GPS - maybe the tach is off?
Not sure if it makes a diff but I also have a 62mm throttle body, K&N air intake and free flowing muffler......

 

so basically what I've learned here is that 3.55s are too small of a difference to be worth my money, and that 4.10s drive like **** on the freeway over 65 mph. oh, and that 3.73s aren't worth my time. Can I get a real answer? what good are 3.55s gonna do me? Even if I found a cheap set of axles, why waste the money?


For the record, I will regear when I go to 33s. But thats a long way down the road, so assume I'm staying on 31s forever.

 

Who said 3.55s weren't an option? That's the most common swap for 5 speed owners with AX-15s and what I have sitting behind my shed to go in in a few months. Are you reading responses from all those AW4 owners?

I never said anything about any ratio not being 'worth it', I am just trying to understand your logic about the whole upgrade path and help you appreciate the following cost/benefit:

3.55:1: Stock ratio found easily in abundance, few hundred bucks for a good set plus whatever your cost to refurbish. Can install yourself. Near stock on 31" tires (slightly under).

3.73:1: Rare ratio, hasn't been stock since D44s were in XJs, would have to buy new gears, have them professionally installed, and refurbish your axles anyway. Deeper than stock on 31" tires.

4.10:1: Stock on 4 cyl gas XJs, highly desirable as complete axles. Few hundred bucks more than most used stock axles depending on market, plus refurbish yourself. Install yourself. Too deep for 31s on the highway, good for 33s.

If cost was your #1 concern or if you have a long commute I'd stick with 3.55:1. If you have a short commute I'd just go straight to 4.10:1s, drive around town in one gear higher than before all the time, enjoy a better crawl offroad, and use the cash saved vs 3.73s to make up the difference in fuel on highway trips. It depends on your Jeeps other duties. Then again for all I know you have a set of 3.73s for $100 and some dude to set them up for free.

Go back and click on the Grimm Jeeper gear calculator again and look at how everything works out. You can do two configurations side-by-side for comparison.

 

3.55 x 26 / 31 = 2.97
3.73 x 26 / 31 = 3.12
You have these two gear choices 3.55 or 3.73 to bring your Xj back to stock parameters. 3.55 would be closer to the stock 3.07 ratio but the 3.73s will give you a little better acceleration. I did the math assuming you will stay with 31s but if going to 33s then the 4.10 gears will be a better option. As stated earlier, you want the math to end up as close to stock ratio for best engine performance.

 

I should point out that we are all just trying to help you out. Tone doesn't come across via text well, so it may seem like we are being dbags, but its not anyone's intention.

So just have a bit-o-patience with us as we try to covey our thoughts to paper...haha

This is a really good assesment of the situation.

Gears are trickey, and not something that just everyone can do. Its also not something you wanna mess up.

Usually regearing is expensive. So most of us really stress that regearing should be done minimally.

Some folks can get it done cheap, but not everyone. And thats a big factor that changes from person to person.

 

One thing the beloved Grimmjeeper calculator does not take in to account is mass.Not only are your tires taller,duh, but they are wider and HEAVIER. More rolling resitince. Probably not running stock wheels either,more weight there. More mass takes more power to get rolling regardless of auto or manual trans. Just thought I would add to the confusion.