I used 185/70/13, Tyres to get rid of hitting on ground issue on jumps. Much improvement found , beside tyre calculator which told that only 02 mm ground clearance will increase. So i decided to find out, what actually overcame this issue. My conclusion is it is not the size of the tyre which did good. It was hardness of the tyre of Bridgestone which does not allow car to go down much.
So :
if tyre sizes are same then car with soft tyres will hit ground, and the car with hard tyres will not hit on most of the jumps.
Whatever size you select , it should be hard tyres, if you want to avoid your car hitting ground, but it will decrease joy ride.
And if you do not want to loose joy ride then opt for soft tyres.
Michelin Tyres are soft, Bridgestone tyres are hard.
Any other opinion will be wellcome.