5.13 or 5.38 gears w/2.7L?

[Incognito]

Dana/Spicer is now offering 5.13 and 5.38 gear sets ( on top of 4.88) for Wranglers with the new M186 M220 axles.
It shouldn't be long before they offer them for the M190 and M210.

Considering that both of the Bronco engines are more powerful, but the M190 and M210 IFS differentials are stronger,...

How big would you go with tires on the Bronco with the deeper gears?
Lockers, LSD, or open size limits?

Sponsored

 

[VoltageDrop]

With a 4.69 first gear in the auto I don't imagine there will be much need for gears lower than 4.70. The F150 comes with 32" tires and 3.55 gears with the 2.7/10AT. That yields 1638 RPM at 70 MPH in 10th gear. On the Bronco with 4.70 gears, to get that RPM in 10th you would need 42.5" tall tires. Gear sets get weaker with lower ratios so I'm perfectly content with 4.70 even if I got to 37's.

 

[kodiakisland]

This is just me, but if I'm running 37+ tires, I don't care what my rpm is at 80+mph. Not sure why so many focus on that unless they are just going to be cruising the interstate. I'm most interested in what happens 0-50mph as that's where my off road vehicle spends most it's time. Especially on 37+ tires.

 

[VoltageDrop]

This is just me, but if I'm running 37+ tires, I don't care what my rpm is at 80+mph. Not sure why so many focus on that unless they are just going to be cruising the interstate. I'm most interested in what happens 0-50mph as that's where my off road vehicle spends most it's time. Especially on 37+ tires.

I used 10th gear as my reference point but I could've just as easily used 2nd gear at 10 mph. The point is 37" (or even 40") tires on 4.70 gears is still what Ford would consider reasonable based on the gearing they put in the F150.

 

[Incognito]

I was just running the numbers on the back of a napkin today. And I'm texting while shopping, so.....

With 33"s, and the 2.3L/6speed and 4.46 gears, it is running 2200rpm at 75mph.
Drop to 5th, and you only bump up the rpms to about 2800. You have to drop to direct, 4th, to get the turbo to kick in at 3400rpm and maintain speed.

With 5.38, you are at 2800rpm at 75 and only need to drop to 5th for 3400rmp and hit the power band.

Crawl ratio also is a crazy 108 to 1.

Sponsored