dual Dana 60 gear question!!
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Joined: Aug 2010
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From: papillion nebraska
Year: 1992
Model: Cherokee
Engine: 4.0
New tyres are 37" in diameter (nominal)
Old tyres are 29" in diameter (nominal - 235/75-15 metric is nominally 28-7/8" static diameter, rolling diameter closer to 28-3/8" or so.)
Click this link - http://www.snoman.com/HTML/axlecalc_5a.html - scroll down and use the third calculator (if you were dealing with a manual, we'd recalculate, the 3.07:1 gearing is a horrible mismatch. But, you've got a good start...)
Per that calculator (and several others, I checked,) you're going to want to go around 4.55:1 gearing in your axles. This is perfectly doable without having to swap axles entirely, and most axles you're likely to swap to will still support 4.55:1 gearing (although a carrier swap will be necessary to change ratios that drastically, as I recall. I don't have the carrier break table handy, but you can ask your gear vendor or check online. Or, if you're going to buy locker/LSD carriers, you can go ahead and just order those at the same time anyhow.)
Old tyres are 29" in diameter (nominal - 235/75-15 metric is nominally 28-7/8" static diameter, rolling diameter closer to 28-3/8" or so.)
Click this link - http://www.snoman.com/HTML/axlecalc_5a.html - scroll down and use the third calculator (if you were dealing with a manual, we'd recalculate, the 3.07:1 gearing is a horrible mismatch. But, you've got a good start...)
Per that calculator (and several others, I checked,) you're going to want to go around 4.55:1 gearing in your axles. This is perfectly doable without having to swap axles entirely, and most axles you're likely to swap to will still support 4.55:1 gearing (although a carrier swap will be necessary to change ratios that drastically, as I recall. I don't have the carrier break table handy, but you can ask your gear vendor or check online. Or, if you're going to buy locker/LSD carriers, you can go ahead and just order those at the same time anyhow.)
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Joined: May 2010
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From: meriden Ct
Year: 2000
Model: Cherokee
Engine: 4.0
well its got 3.55 so no. 4.69 would be exactly the same as stock on 37's. I like to go a little deeper than stock to help with ire weight and leverage off road. I run 4.88 with 35's and I think its a pretty good combo.
A 5.13 could still put you at 2272 RPM at 65 mph and 2620 at 75 so not bad at all. thats what I would do. 5.38 would probably be best off road but would sacrifice a little at highway speed.
A 5.13 could still put you at 2272 RPM at 65 mph and 2620 at 75 so not bad at all. thats what I would do. 5.38 would probably be best off road but would sacrifice a little at highway speed.
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Joined: Jan 2010
Posts: 139
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From: Eagle County, Colorado
Year: 1996
Model: Cherokee
Engine: 4.0L I6
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