Easy wheels

[fierce beagle]

Hey I'm a brand new owner to a 73 Indian parts rig that the PO said was some sort if commercial heavy duty outfit, and a 72 brave D20. Bought the Indian for the 440 to put in my 69 gtx.
My brave has the 16" split wheels while the Indian has regular 19.5 wheels. I am real cheap and trying to get away from the split rims.
I would like to swap the entire rear end from the leaf spring perches down in order to get solid wheels, brakes with boosters, and heavy duty axle. Up front I would swap the the entire cross member down to get disc brakes and solid wheels.
I took the measurements and everything looks like it would fit.
The only thing I don't know about is the rear end gear ratios. I couldn't find any tags on the diff housing. From the taller tires I know I'll lose some power. PO swapped a 360 I to the brave, so that helps.
Anybody know what my gear ratios are? How do I determine what I have in each?

[Surfinhurf]

Tools needed
A flat surface
Masking tape
4 feet of string
Chalk (for marking)
Hydraulic jack with stands (if needed)
Simple five steps
Park your rig on a flat surface.
Tape one end of the string to the bottom (6 o’clock) of the rear drive shaft. Using a clock method to determine location, bottom would be 6 o’clock, and the top would be 12 o’clock.
Mark the rear tire where it touches the ground.
Now push your rig forward so that the tire make one full rotation
Look at string on the drive shaft.
The string will wrap around the drive shaft and the amount of wrap it has will tell you roughly what gear ratio you got.
Example:
If the string is wrapped around the drive shaft 3 ½ times than you have the 3.50 to 1 gear ratio.
If you got the string wrapped around 4 ¼ times than it will most likely be 4.11 to 1 gear ratio.
If it is wrapped 4 ½ times than it will be 4.56 to 1.
If it is wrapped 4 ¾ times than it will be 4.88 to 1.

If you don’t have room to move the rig, here is another way to do it. Instead of pushing the rig just jack up on rear tire and rotate it one full turn with vehicle in neutral. Count the number of wraps and times it by 2. The total is what you use to figure the gear ratio. Note this procedure will only work with open diffs.

[fierce beagle]

Awesome! I'll do that when I get home.
Thanks

[Rickf1985]

Or you could pull the diff cover and the ring and pinion gears should be marked with the tooth count right on them, divide ring gear by pinion gear. If they aren't marked just count the teeth on each and do the math.

Surf, I like the string idea, I usually just counted revs of a chalk mark. String is MUCH easier.

[fierce beagle]

Are there any negatives to going with 19.5" 5 lug wheels?

[Rickf1985]

None that I can think of but do your homework because I have seen this conversation come up many times before and I seem to remember there is some reason the swap is not as simple as it sounds. Dave is the Doge guy on here, he has been pretty busy but hopefully he will see this and chime in.

[fierce beagle]

Thanks Rick for the response.  Thought I'd repost the question for additional feedback.
Are there any negatives to swapping entire rear end and front end out from a 73 Indian 19.5" 5 lug wheels on to my 72 brave that has 16" 8 lug split rims? I would swap from the spring mounts down.

[Surfinhurf]

Just a couple of questions I would ask:
Will a 19.5" wheel fit in the wheel well, both height and turning angle
What is the gear ratio in the new rear end,(with taller tires) and will it be enough for the 360 engine in your rig
Will the 5 lug hub support your GVW
Is the axle width the same
Will you need to modify your driveshaft, IE is the pinion yoke in the same position (fore/aft)
Will you need to modify your hard brake lines and emergency brake
Will the front axle clear your engine/transmission/exhaust
Will the shock mount on the new axles allow the shock to mount to the old shock mount on the frame
Is the axle diameter the same or will you need new u-bolts
Your rig will sit higher, will you need to modify your step?

Good luck, post pics

HURF

[fierce beagle]

Thanks, perfect questions.
Might take me awhile to check that all out, but I'll get back to you all with progress.

[kb2crk]

I know this is a few months late but the 5 Lug axles are rated for a heavier weight than the 8 lug. The front axle with the 5 lug is usually rated for 4000 llbs and the rear with the 5 lug should be a Dana 70 HD rated for 10,000 lbs. A lot of the 440 RV chassis had a 4.56 ratio rear. Hope this helps some.