If my current tire size on my atv is 24x10x11 (Rear) and 24x8x12 (front) and i have new ITPs and there 25x10x12 (front) 25x8x12 (rear) Will they fit? im worried about the rear size being differnt. please help!

 

No, they will not fit. Your rear rim size is 11 inches. The new tires are 12 inchers.
Your new tires:
25x10x12 is a rear tire
25" overall diameter, 10" width, 12" rim size

25x8x12 is for the front and will fit your front rims
same as above but with an 8" width.

I am guessing you have a Rancher. If you can find some rear wheels from a Foreman 450 or 500 they should work. Or else get all new wheels.