Need better gear ratio.

[AzFrank aka Desertson]

Alright you guys,differentals are not my strong point. I have a 79'Cherokee w/ Quad-Trac+ reduction unit, and stock Dana 44 frt-rear.What would be a better gear ratio to put in.
Its daily driver and weekend wheeler.
Thanks!

[RamJetFSJ]

What size tires do you have?

[AzFrank aka Desertson]

32x11.50. After I logged off I realized I forgot the tire size.Doooh!
Thanks RamJet

[RamJetFSJ]

If it were me, Id do 3.73s or maybe 4.10s if your not worried about gas milage and want some more performance. The 3.73s will give you a 65mpg cruising RPM of about 2614. 4.10 will give you 2873 rpm, which is starting to get a little high for the AMC motors.

Im putting 4.56s in my rig, with 32s but I have a overdrive 700R4 and a motor that doesnt mind whining down the freeway, and want maximum acceleration... With my OD, 4.56s and 32s, at 65 Ill be turning 2200 rpm.

Check this link out for a neat calculator to figure out what your RPMs will be on the highway with different gears/tire sizes.

http://www.ring-pinion.com/calculators.shtml

[derf]

With an automatic (the Q-Tracs came with autos) the final RPMs at 65 will be about 10% higher.

With 32's, 4.10 gears will give you a good off road performance without completely killing you on the highway. 3.93's or 3.73's will be a little better balanced. 3.55 or 3.31 will be better for highway.

If you go above 3.73 gears, you'll have to replace the carriers in your axles (the part the ring gear bolts to and that holds the spider gears). This will raise your cost.

[RamJetFSJ]

Those numbers I gave should take into consideration a auto with a non lock up coverter (the 10% should already be taken into consideration).

The calculators at randys ring & pinioin are great. Do the conversion for any speed, any gear, any tire and get #s for Auto, Auto OD, manual, and Fifth Gear Manual OD

I forgot about 3.93s. That would be a better choice that 4.10s I believe...

[AzFrank aka Desertson]

Thanks guys for the help,Now comes the fun part,asking the wife for the OK.I wear the pants in the family,she said I could tongue.gif !LoL