ECODIESEL DIFF RE-GEARING

[Tpsillos]

4.56s with 37s pencils out to be about even with the stock tires on 3.73s.

i'm using 4.56s with BFGs 37s right now, and while it works OK, i'd be happy with a slightly larger tire (like at least a Mickey, or maybe something in a 38).

4.10 would be closer to factory than 4.56 with 37s.
But with a stage 2 tune it was fine with 40s(Baja boss m/t)and 4.10. Now the first two gears are pretty useless, all it does is change gears now until I hit 45 then it’s in 8th.

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[zouch]

"closer" isn't all there is to it; i'd rather gear a little deeper than not deep enough.
(and FWIW, i started out with larger tires than your example.)

being lower helps make up for the increase in rotating weight, increased wind resistance from larger tires and more drag associated with lift. (not to mention the increasing weight of the vehicle).

(that, and personally, i have a 2.72:1 t'case, so lower puts me more where i wanted to be when crawling.)

ideally, i would have been able to find gears around 4.3x from a reputable manufacturer, but 4.56s also put me closer to a slightly larger tire size if that's what i choose to do.

adding more power while making the engine turn over slower doesn't seem like a good recipe for cooling, either, but i play where it's hot, so that's not a consideration everyone needs to make.

4.10 would be closer to factory than 4.56 with 37s.
But with a stage 2 tune it was fine with 40s(Baja boss m/t)and 4.10. Now the first two gears are pretty useless, all it does is change gears now until I hit 45 then it’s in 8th.

 

[Tpsillos]

My Jeep came with 255/70/18s which is where my calcs came from. Also not a Rubi case but I have one to try and install when I figure out how to make it work(doesn’t fit, it was an amw 392 swapped t case with their adapter).
I have no complaint with the low gears off roading which I do alot of but it’s also my DD. I am from the south east so it gets hot but I have an egt gauge and have had a dozen diesels, two with over 1000hp still.
But driving over 70 mph the rpms are to high draining fuel and city driving is a bummer bc 0-60 is almost twice as slow now.

 

[Ratbert]

ideally, i would have been able to find gears around 4.3x from a reputable manufacturer, but 4.56s also put me closer to a slightly larger tire size if that's what i choose to do.

I'd avoid nonstandard gears if at all possible. My 4.63s were a nightmare to deal with. If/when something happens you're stuck waiting on the replacement. Or, like mine, the one company that makes them no longer makes them.

Fortunately I'm on 4.56s now, all paid for by AEV to make things right.

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