Gearing for dummies

[1BADMAZDA]

Hey guys new to the site.
Just traded my 00 mustang for a 94 mazda b-2300. Mustang had some issues! plus I really missed having a truck.
I think it was an even trade this truck is lifted with all the goodies

This thing wont pull 4th very well and 5th non exsistant
this truck has a 6in lift with 32x11.50x15's

what size gearing should I run ?

 

[Hahnsb2]

4.56s at least.

 

[Ozwynn]

+1............ 4.88 or 5.13 if you want to go to 35" tires.

 

[Chris.S.]

Yup, what they said.

 

[1BADMAZDA]

thanks!

 

[Will]

What I would do is drive your truck and figure out where you want the motor to be at cruise speed. The rule of thumb is that you should be in a gear where you can still accelerate. So if you decide the motor feels the best. Say, 2,800rpm. Then use the spreadsheet I attached and plug in your tire size then your 2800rpm (or whatever) in the Engine RPM box and play with the Axle Ratio until you get the speed you want in 5th gear.

Or use it any other way you want. But I would do a lot of thinking so you know exactly what you are doing when you change the gearing.

 

[doorgunner]

I did a fast check in the Tech. Lib. and a rough estimate would be for each 1 inch increase in tire diameter, you need to increase the gear ratio 0.15 (or more)

30" diameter stock size tire
35" diameter of new tire
5" difference of tire diameters
0.15 x's 5 = 0.75 increase needed in differential
3.27 oem ratio differential + .0.75 increase = 4.02 (4.02 rounded up to nearest available ratio) = 4.11ratio(or more)

Edit: does this look kinda right (I may or may not know wut I'm doin)/never mind-u alreddy got good
advice.