Ok, so I believe my 1999 TJ has stock gearing but I don't know. It has a 2" body lift and they put on 33x12.5x15 tires. How can I find out what gearing is in there now without pulling the diff covers off and counting the teeth? I got the rear tires off the ground and put a piece of tape on the drive shaft and tire and with 1 rotation of the tire I get about 2 1/4 rotation of the diff. I saw a video of a guy doing that and he got about 4.5 rotations on the diff to 1 rotation on his tire and he said he had installed 4.56 gears so that was about right. With that math I have 2.14 gears which doesn't make sense. I'm assuming it's because of the bigger tires?
Need help figuring out my gearing
- Thread starter Lilbomb
- Start date
Tire size makes no difference. Watch the whole video, it talks about open diff and locked diffs which are determined differently.
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For open diff, jack up only 1 wheel. Spin wheel 10 times and count DS rotations. Double DS rotations and then move decimal point to the left 1 time. That is your gear ratio.
Example
10 tire rotations = 18.5 DS rotations
18.5 X 2=37.0
Move decimal point left 1 position. 3.7
So, that would be 3.73
Example
10 tire rotations = 18.5 DS rotations
18.5 X 2=37.0
Move decimal point left 1 position. 3.7
So, that would be 3.73