If there is the same gearing ratio in the axes and transfercase ,why are diferent sizes in the oem.tires, can I install the same height,example
24x8x11 front and 24x9x11 insted of the 23x8x11 and 24x9x11

 

I would not recommend your tire scenario. I'd keep the ratio the same. The Honda 300 4x4's have smaller (in diameter) tires in front. If you put taller tires on the front I'd keep the same ratio, so if you went with 24" front tires then I'd put on 25" rear tires.

 

The front and rear indeed have different ratio's. However, a lot of the people around here, that only ride in the mud, run 26 inch tires all the way around. They don't drive or handle very well on hardpack, but not much of a problem in the mud. I wouldn't recommend different size tires unless you would be using them in mud only.