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| | | | Joined: Sep 2006 Posts: 42 Wrench Fetcher | | Wrench Fetcher Joined: Sep 2006 Posts: 42 | Hi guys, Just trying to figure out my rear end gear ratio without taking off the rear cover. If the input pinion makes 1 full turn and the tire turns 66% of a full turn, what's my gear ratio ? | | | | | Joined: Jul 2004 Posts: 5,708 'Bolter | | 'Bolter Joined: Jul 2004 Posts: 5,708 | oldkoot,
Here is a procedure I have seen posted on this site...I can't take credit for it. See if it works.
"Jack up one wheel. Mark the driveshaft and the wheel. Make 2 complete revolutions with the wheel & count the turns on the driveshaft. It should be fairly close."
Stuart | | | | | Joined: Sep 2006 Posts: 42 Wrench Fetcher | | Wrench Fetcher Joined: Sep 2006 Posts: 42 | Stuart, If thats correct, and I'm doing the math correctly, the drive shaft will turn 3.3 times around for 2 revelutions of the wheel. | | | | | Joined: Sep 2006 Posts: 42 Wrench Fetcher | | Wrench Fetcher Joined: Sep 2006 Posts: 42 | So I'm going to guess that I would have 3:31 gearing in my rear end as this seems to be the closest GM gear ratio I can find. | | | | | Joined: May 2005 Posts: 8,878 . | | . Joined: May 2005 Posts: 8,878 | To get a more accurate guesstimate turn one 10 turns while you count the other, then calculate. | | | | | Joined: Jun 2005 Posts: 46 Wrench Fetcher | | Wrench Fetcher Joined: Jun 2005 Posts: 46 | i'm guessing its closer to a lower 3 series, unless its a posi rearend, you have to make 2 revolutions of the rear wheels to count the revolutions made by the driveshaft, so 2 divided by your .66 comes out 3.....there are 3.07 & 3.08 rearend gears, just depends on what the rearend is out of. | | | | | Joined: Sep 2006 Posts: 42 Wrench Fetcher | | Wrench Fetcher Joined: Sep 2006 Posts: 42 | This is out of Caprice Wagon or Police Special as it has 12 x 2 brakes. | | |
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