Speedo pinion question

[Torkmnstr]

I have the stock pinion in the tranny and it pegs my speedo. I am running bfg's 295/50/15 with a 3.91 gear. So my question is with my diameter at 26.6 tall tire should I go with a 37 tooth gear? I have looked at charts and my diameter falls in in-between the 36 tooth and 38 tooth, with no definite tooth size for my diameter. Anyone else run the same setup? Thanks all.

 

[minnesota guy]

With that tire height, I would run a 39 tooth gear. Factory speedo's were off. My experience is to go up to compensate.