Can Anyone tell me what ratio my gearing is & what tire size best suits
My code on the id plate is
A343H G254

 

G254
G = 8" axle
25 = 4.56 31" tire option
4 = 4 pinions V6 rear carrier

So basically a 31" tire suits your gear ratio you can run 32's with minimal power loss. If you come across a salvage truck or 4 runner with the G144 option definately pull the diff's the 14 = 4.875 ratio that would be ok for 33's.

Here's a good tech ref if you want to indentify another axle:
http://www.off-road.com/toyota/tech/other/4_axles.html

 

Oh
I was thinking of dropping down to 30's to improve mileage around the city

 

I checked the size of my spare & its only 30" so I guess thats what this had standard.
I put them side by side there is very little differance.