According to this you should only be at 1978.73 RPM with that setup..you sure? Thats a 1100 RPM difference.
http://www.rocky-road.com/calculator.html

 

Thats the plan. I'm either going to buy 2X 4.10 axles or 2X 3.55 axles.
My only concern really is 4.10 being too low and cruising RPM being too high and bad for engine & mpg. I do drive 70mph sometimes.

 

Yeah, That is a really cool chart.

70? Is that all? This '92 really likes 75 but feels a little light @ 80. It has a real grove @ about 73mph.

Both hands on the wheel!

 

I was thinking the exact same thing.



That speedometer must be wayyyyy off. Passing a lot of people at 60mph, perchance?



Joe
EndlessMtnFab

 

I didnt think the speedo was that off, I must be wrong, Time to take another trip down the highway

 

Why not split the difference with 3.73s? Tow package XJs and ZJs have that gearing. And its not uncommon to see 3.73s in the Explorers too. I've got 31s on my ZJ and on my Explorer both with 3.73s and I don't recall my RPMs, but even with BB lift I can still pull 19-21 MPG averages. The EX is a bit heavier and more square and gets just under 18 for average.

Just another option.

 

Ya, I've thought of that, but I figured that a D30 with 3.73 would be a hard find. I'm gonna test out just driving in 4th gear for awhile. It ends up being about the same ratio as 5th gear with 4.10's.

 

so on that chart you have listed....do you wanna stay in the green????? cuz if that is the case then 4:10's is what you want....cuz at stock with 3:55's which is 27 or 28 tire then you are in the green..unless u have a manuel of course....jus thought i would throw that out there..that if bein in the green is what you should be in then 4:10's would be the way to go



http://jeephorizons.com/tech/rpmchart.html

 

4.10s all the way! I'm going to go up to 31's soon and I'll run 3.55s until i can find a 4.10 D30 and a 4.10 8.8 with disks and LS!

 

One thing that chart doesn't mention is another variable which is your final transmission gear. Its using 1.0 for it, which is a manual 4th gear ratio. 5th gear is 0.79. Somthing to consider.

I deduced this from using this site that someone kindly provided earlier.
http://www.rocky-road.com/calculator.html

 

good point....i didnt know if any of the variables changed since u have a manuel.

 

31's and 4.10's is where it is at. I am sitting at 30's and 3.55 and want to regear.

I would not pay to regear to 4.10 though just get a 8.8 out of an explorer and a 4cy dana 30 they should be stock 4.10