Gearing question

EarthX

Owner of Earth Exploration Technologies
 
Joined
Mar 6, 2005
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After driving around on my 38s I've decided it's time to re-gear. Now all this gearing stuff is a little over my head right now. I hoping someone will help me calculate what gear I need.
The rig is now set up like this:

fj80 axles with 4:11 thirds
stock slit case
4l60e tranny
38" tires

With the 38s I think I'm feeling the tranny slip while driving up hill while under hard power.
I bolted up some 275/70/16 tires I had sitting around and the difference is amazing! Until I re-gear I may run these, even though it looks ridiculous.
What would be the equivalent of the 275/70 in r&p gears?

Someone educate me.:cheers:
 

EarthX

Owner of Earth Exploration Technologies
 
Joined
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Perfect. Thanks for the link.
I think you're right, 4.88s seem to be the sweet spot.
 

EarthX

Owner of Earth Exploration Technologies
 
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Ok, after messing around with that calculator a bit more, Im having a had time deciding which would work better; 4.88s or 5.29s. At 70 mph, 4.88s should put me right around 2114 rpms. 5.29s around 2292. Not a whole lot a difference. Im thinking that the 5.29s might make up for that slightly higher rpm with great low range performance. Any thoughts? Does those rpms seem to high for highway use?
 
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you start to sacrifice some strength once you move past 4:56. You also may need to ground down your ring on a ratio higher than 4:56 with and ARB.
 

EarthX

Owner of Earth Exploration Technologies
 
Joined
Mar 6, 2005
Messages
904
Location
Lake Arrowhead
you start to sacrifice some strength once you move past 4:56. You also may need to ground down your ring on a ratio higher than 4:56 with and ARB.
Ive heard mixed opinions on the strength of 4.65's. I wont be going higher than that and whatever I choose will be cryo treaded, Im not worried about the strength. Also Im runner factory elockers so no ARB for me.
 
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