Great point that's often overlooked. Remember, you're now going further than what the odometer indicates.

 

The change from skinny 32s to skinny 33s is no biggy.

Assuming your speedo is accurate with the 32s, when you change up to 33s from the 32s, your actual/real speed when the speedo reads 70mph is 67.87878788mph.

Minimal difference in fuel economy between the two doesn't justify all this thought process. Get your new tires already!