Yeah, it's hard-core tech, I know. :shaking: :emb3: but I've been searching for a couple of weeks on this and can't find shit. Does anyone know what gear tooth count to use in the TJ 231 t-cases for use with 5.38's and 37's? Every table I can find stops at 4.88's. I tried a few that I had sitting in the garage but they were all off. I don't care if it's a little bit off, but the 'ol speedo says I'm cruisin' at 50-60 mph in 2nd gear :grinpimp: and I'd like to know how fast I'm actually going when I'm headed up to the trails and getting flipped off :flipoff2:

5.38 and 38" SX (spare mounted on rim measures 38.5" tall), I'm using 40 tooth speedo gear and my speedo is right on, verified with my gps.

Thanks, but my 37" Irok's are measuring about 36 1/2" mounted. It's got a 36 tooth gear in there now, maybe I'll give a 38 or 39 tooth gear a try.

With 37" Iroks (36.5) and 5.38's I use a 39 tooth gear, not sure exactly how accurate but it seems pretty close.

Let us know how you make out, Good Luck.

Cool, I'll pick one up and see how it works, thanks!