Bigger tires.
 

This might be a stupid question, but here it goes. I just swapped the wheels from my parts car to my runner. The new wheels are the 225 60 R14 and the old ones are 195 60 R14. Visually,the difference is small, but there's noticable difference in driving characteristics. I'm getting more road noise. I sorta expected that since there's more rubber on the ground. I also expected there to be a change in acceleration and even mileage, but what I'm wondering now
is how do I recalibrate the speedo so that reads right. I'm usually pushing right at the limit and in Alameda, the cops are no joke. It's a mostly residential town so I wanna be sure that when I'm reading 25 I'm not going 30.

Any help is greatly appreciated.