thanks.
I don't have an idea about a brand to buy yet.
So i checked a general site (http://www.tyresizecalculator.com/tyre-wheel-calculators/tyre-size-for-rim-size-width-calculator)
According to that for 7.5 Width and 40 profile, ideal is 215 or 225 and the max i can go to is 235.
So there goes my 245 plan