Axle swap for better gearing

I have a 92 b2200 5speed. At 70mph im running about 4500 rpm. I would like to swap out my gearing or axle to bring my rpms down at freeway speeds. I have a 1980 ford courier axle laying around. Would swaping the courier axle be any better? The courier axle came out of a courier with the ford 2300 motor.

with the stock tires (205/75/14) your truck will go 104mph at 4500 rpms. that tire is about 26.1 inches tall.

"Oh, so i need a 15?" NO. a 205/50/15 is only 23 inches tall, that translates to 92 mph at 4500 rpms.

You must be running a tiny tire to only get 70, or your clutch is gone.

you need a tire that is about the same diameter / tall as the original.

Im running a 16 rim with a 45 series tire.. Clutch is good, i cant run a bigger tire, or i wont lay out.

your tires are like 23 inches, thats why.


check the gear on that other axle. spin the drum exactly one revolution and have a buddy mark and count how many times the pinion spins, your mazda is a 3.9 to 1, you looking for less, like 3 - 3.5 to 1. it might work

So that explains why my gearing is so : . Well theres no way in hell im running a stock tire. Also, i posted in Modification tech. I still would like to know how to modify my truck more to get around this problem. Freeway speeds are unbearable. i feel like my motor is going to blow going down the freeway.