Gear Changes..

[ClarkGriswald]

Somewhere around here I remember seeing an article that explained how ya figure out what R&P ya need to change to when you put on big tires.. does anyone remember where that is?? Or just know what the proper ratio would be to change to in order to run 33's on a 88 Grand Wag. it has 2.72's now and 235 tires.. Also my D44's arent marked on the axle tubes at all like the descriptions I have found as to how to ID them.. there is a lot of printing on the diff covers and a tag between two bolts on the left side of diff cover.. both of these side tags have 2 72 on them so I assume since it is the only number common to both axles that this is my ratio. How do you know if you have the trac lock rear end or whatever they call it? my rear and front axle's seem to have a slightly different shape ONLY on the bottom of the housing.. the front has a kind of tab of metal hanging down where the rear is more rounded. but they are shaped the same I'm sure they are both 44's. (pretty dang sure) they both are stamped with dana and the triangle symbol.... thankx for any info ...

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88 Grand Wagoneer
D44's front\rear
AMC 360
TF 727
NP 229 (Funky)
Bone Stock (for now)
NO RUNNING BOARDS!

[Ralph]

2.72:1 is indeed the gear ration of your differentials. As for Trac-Loc, I'm fairly certain that was never available for a 2.72 differential, as it was used in the axle of vehicles with factory towing option and 3.31:1 axles.

[ClarkGriswald]

Ok that is a good answer that I will buy.. thanx.. um. found a tiresize \ gear ratio calculator if i go from my 2.72 gear ratio with 235\75r\15's to 33's the optimum ratio was 3.11, 3.39 for the more torque low end side.. anyone running 33's out there? what ratio are you using?

(And how come I have to keep editing my message's cause I continually spell ratio, "ration" hahaha. dangit.. )
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88 Grand Wagoneer
D44's front\rear
AMC 360
TF 727
NP 229 (Funky)
Bone Stock (for now)
NO RUNNING BOARDS!

[This message has been edited by ClarkGriswald (edited August 07, 2000).]

[BIGUGLY]

4.09's with 33's. But it's not an every day driver. Great off road.

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79 Cherokee
BIGUGLY
360 Stroker/TH400/QT/44's
edelbrock performer pac
3"lift 33x12.5

[ClarkGriswald]

Yeah I bet that rocks with 4.09's and yeah I drive mine all the time so would want to stay close to how it runs stock mabye a hair to the lower end side

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88 Grand Wagoneer
D44's front\rear
AMC 360
TF 727
NP 229 (Funky)
Bone Stock (for now)
NO RUNNING BOARDS!

[joe]

Here's a couple of formulas to play with:
rpm=mph*gear ratio*336/tire dia.

What your new effective gear ratio will actually be after installing larger tires:
new ratio=old tire dia*old ratio/new tire dia.

What new gear ratio you need to install to get back to your original ratio after adding larger tires:
new ratio=new tire dia*old ratio/old tire dia.

On the last one keep in mind that big tires weigh a lot more so you'll lose some power there. Rather than regearing to get back to original I'd go with the next lower gearing(higher numerically) to compensate a bit for the added weight.

Have fun, all it takes is money... http://www.cs.colostate.edu/~zeimet/ubb/wink.gif
-joe

[porkchop]

Hey clark where did you get that calculator. I lost the link and been trying to find it for awhile now. Thanks.

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'67/'79 Wagoneer mix
Body of a 33 year old
Heart and legs of a 21 year old.
360,TH400,QT,D44's F&R
32X11.50's

"I regret that I have but only one paycheck to give to my Jeep."

[ClarkGriswald]

There are a few that I found.. here they are...
http://www.ring-pinion.com/RPMCalculator.html
http://www.4lo.com/



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88 Grand Wagoneer
D44's front\rear
AMC 360
TF 727
NP 229 (Funky)
Bone Stock (for now)
NO RUNNING BOARDS!

[Marc_01]

Porkchop,

Richmond gear has the calculators also: http://www.richmondgear.com. And they have info on what ratios are availible for the D 44's.