Above all, do not mix bias ply and radial tires on the same motorcycle unless it is with the approval of the motorcycle or tire manufacturer. This is possible in some cases, but again, it should only be done with the approval of the motorcycle or tire manufacturer. When considering wider tires, you must factor in clearance for both width and diameter, the effect on stability and handling, along with whether your rim is wide enough. If wider tires are approved for a motorcycle, it is usually permissible to increase by only one size designation. When fitting a larger tire, always allow for some tire growth from the new to used situation.
All tires increase in size after they have been inflated and are run for a few hudred miles.
When a motorcycle manufacturer decides on the tires for a particular modiel, they make sure that the speed rating of the tire meets the maximum speed capability of the motorcycle. If you fit higher speed-rated tires, there is a good chance that you will sacrifice some other performance aspect such as mileage. This being the case, it is usually best to stay with the speed rating of the original tires. They're all you really need. Definitely not when they are worn smooth, or worse, when they are worn to the carcass.