Gearing vs. tire sizing

[iceman]

Hey, great site. I found the gearing and tire calculator and would llike to know the difference between using larger tires vs. the 5th gear swap to lower rpm. I know that the 5th gear will only change 5th gear but how is rpm affected when using larger tires? Your calculator doesn't have a slot for that.

[BillK]

Larger tire will lower rpm regardless of the gear. Every gear will go down the same percent.

[iceman]

What I mean is what is the gearing for every gear so I can put it into the calculator. This is for a '98 jetta.

[chittychittybangbang]

Here is what you want:

gear - ratio
1 -----3.777
2 -----2.117
3 -----1.360
4 -----0.971
5 -----0.755

final drive - 3.157

This is for a 02a CTN 5 speed transmission for the 1Z AHU engines. I didn't put it up because 5th gear is the most relevant to a 5th gear swap. You will also want to change the speed input field to see what engine rpm the engine will be at. Here is the link to the tire, wheel, gearing, and engine rpm calculator - http://www.myturbodiesel.com/1000q/tirewheelCalc.htm

[iceman]

I think you reversed 1st and 2nd gear, I put in the numbers and they don't match up with what I see.

[chittychittybangbang]

Whopps! I read the manual too fast, 1st is actually final drive. The listing is now fixed and should be correct.

[iceman]

Great, these new numbers seem correct. 1st gear is so low that I wanted to raise it too, not just 5th.