High gears?

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g49bridges

g49bridges

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Hey guys, this is not really an A body question, but figured maybe some of you mopar gurus might have some insight. My non A body car, a 68 charger, has a 8.75 rear. I recently started going through the car to see exactly what I had. Jacked up the rear and turned the wheels and it's definitely an open case, but the odd thing is the gears...1:1 ratio! One rotation of the tire is exactly one turn of the pinion. I know it used to be a circle track car, but that's about all I know about the car. Has anyone ever heard of such high gears? Because I have not!
 
If it's an open differential, you'll need to keep one tire on the ground then count the revolutions as the spider gears will allow the other tire to turn and not be accurate.
 
I dont even see how this is mechanically possible. Like to hear this one as well
 
Dubob said:
If it's an open differential, you'll need to keep one tire on the ground then count the revolutions as the spider gears will allow the other tire to turn and not be accurate.
Click to expand...

This is wrong, you need to turn both tires at the SAME TIME, 1 revolution (might require a helper) and count the driveshaft rotation.
 
If you turn the shaft instead of the wheels then both wheels usually turn and you don't need a helper to try and do "Synchronized wheel exercises"

Same result, just going at it from the other direction.

A piece of tape or something on the shaft and a tire both will help keep your counts.
 
Dubob said:
If it's an open differential, you'll need to keep one tire on the ground then count the revolutions as the spider gears will allow the other tire to turn and not be accurate.
Click to expand...

Right as far as it goes, read onswards

replicaracer43 said:
This is wrong, you need to turn both tires at the SAME TIME, 1 revolution (might require a helper) and count the driveshaft rotation.
Click to expand...

RustyRatRod said:
THIS is correct. ^^^^^
Click to expand...

NO, no NO!!! Here's how you "do" an open rear end, and it's easy!!!

You DO leave one wheel on the ground!!!

And you go around and turn the jacked up wheel TWO revolutions while counting driveshaft turns. That will directly give you the ratio, IE 3 1/2 "plus a bit" is 3.55, etc

If it's limited slip (suregrip) then you jack up both wheels, and turn either wheel ONE turn, counting the shaft
 
67Dart273 said:
Right as far as it goes, read onswards





NO, no NO!!! Here's how you "do" an open rear end, and it's easy!!!

You DO leave one wheel on the ground!!!

And you go around and turn the jacked up wheel TWO revolutions while counting driveshaft turns. That will directly give you the ratio, IE 3 1/2 "plus a bit" is 3.55, etc

If it's limited slip (suregrip) then you jack up both wheels, and turn either wheel ONE turn, counting the shaft
Click to expand...

More than one way to skin a cat I would say! I never thought about the number of turns trough the spider gears and figuring it that way........ sounds reasonable.
 
I have done it both ways and it comes out the same. If you keep one wheel on the ground and do it, then simply multiply your answer by 2.

It works fine either way. You can turn both wheels together as long as they stay together the result will be the same.
 
Ok, that makes much more sense. I never knew you needed to keep one wheel on the ground with an open case! Good info guys, thanks. I will do that as soon as I get a chance this weekend.
 
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