Currently have 17" oem alloy rims on my 2010 accord coupe. Thinking about getting 18" premium oem rims. What differences in ride quality should I expect and should there be any mounting troubles?

 

No mounting issues, the ride maybe slightly stiffer as the rubber of the side wall will have to be smaller. To get the correct size use Tire Rack, when entering vehicle info you can choose plus 1 on tire size, that will tell you the 18 inch tire you will need.