So, I've been doing some research on this subject and attempting to find out what options do exist on the C200 as it relates to gear ratios. I think I've finally found what I was looking for. It looks like you can buy a replacement gear set from Nissan for the C200 Rear End, and change your final drive gear ratio. There are only a couple of options so you may not get where you want to go, but for some of us this may be an options.
So here are the facts on the gears in the C200 rear end:
Model - Gear Ratio - Number of Teeth (Gear/Pionion)
QR25DE KC M/T 4x2 - 4.083 - 49/12
QR25DE KC A/T 4x2 - 3.692 - 48/13
VQ40DE KC A/T 4x2 - 2.937 - 47/16
VQ40DE CC A/T 4x2 - 3.133 - 47/15
VQ40DE KC A/T 4x4 - 3.133 - 47/15
VQ40DE CC A/T 4x4 - 3.357 - 47/14
What this means is if you've got a 4 cyl. KC M/T then you've already got the deepest set of gears Nissan has for this drive, but for everyone else on the list it looks like you've got at least one set of gears to switch to. On courtesy parts these gear sets go for
about $500, but you may be able to find a used set for less. I am not sure if you will need to replace the differential case or not (it looks like there is a 4 cyl and a 6 cyl case) or if the dealer will do this work for you. But I called my local dealer to get this information and we seem to be heading down the path of them doing the work.
For me it looks like I can go from 3.357 to 3.692 or 4.083 Now if you use a calculator (like the one at
4Lo.com) you can determine what your new gear ratio should be to compensate for your bigger tires. For example if I were to go from 30.5" to 32.8" tires the new gears should be 3.61:1 and Lo gears (e.g. for rock crawling) would be 3.94:1. So this seems to tell me that for my "new configuration" I should go to the 48/13 gears (3.692) out of a 4 Cyl A/T and I'll be back to an optimal setup. Otherwise my effective ration will now be 3.12:1
NOTE: If your model is not listed here, then you've got the other rear final drive and I did not get the specs on that.