gear ratio question

[sonic1]

I was just playing around with one of the top speed calculators and I bought a torque converter kit for my 212 predator I put in a go kart which is strictly got off road use, and the kit came with a 10 tooth and a 12 tooth sprocket, my axle has a 60 tooth on it and I went with the 10 tooth for the 6:1 radio but on the top speed calculator it says with a 10t I can get 32 mph and with a 12t I can get 39mph, should I stick with the 10 or go with the 12 to get the extra 7mph? Or will that screw up the ratio, I'm still really new to all this so any help is appreciate

 

[jeep2003]

id probrobly go with the 10 tooth and if its winding out too much then consider changing up the ratio. Its safer to do that to save the belt. and if you are offroad only top speed will probrobly rarely be reached even with that ratio