Select a synchronous round.
Click the round value handle (1).
Type a value in the Edit Dimension Value box and press Enter.
Note:
You can also use the scroll wheel on the mouse to dynamically edit the radius value. The scroll behavior is controlled by the Solid Edge options→Helpers page→Enable Value Changes Using the Mouse Wheel option. If the option is unchecked, use Crtl+mouse wheel to change the value. If the option is checked, use the mouse wheel to change the value.