Tire sizing and handling.

[be350ka]

I am hoping that someone can give some input on tire sizes and the associated handling characteristics when mounted to a fixed rim size. For example, I have a 696 and the front tire is a 120 60 17 and the rear is a 160 60 17. Obviously, Ducati has a reason for that sizing. But, the question I have is what made them go with these sizes. Would a 55 be terrible in some way? Or what about a 70?

Now, what about width? On some tire manufacturer sites it gives you the minimum and maximum rim width for certain tires. My rear rim is 4.5 wide and aparently can handle up to a 170mm tire. What type of handling characteristics would I notice from going to a 160 to a 170? What if someone put on a 180 or 190?

I am new to the motorcycle game, but I have been playing with mountain bike tires for some time now and there are pros and cons to these types of variations. For example, a wide tire on a narrow rim will tend to roll when pushed hard. Is this same for motorcycle tires?

Thanks guys. Just thinking out loud here and trying to understand the correlation between rim width and tire profiles.