The rule of thumb I've always heard was that you could go one size wider if you went down a size in aspect ratio which is what you have done. I went from 215/65/17 to 225/60/17 on our 2001 and the speedometer was perfect when I checked it over a 10 miles stretch of interstate.
2001 GC ES, 207K miles, Chrysler 2000,000 mile club license plate holder
2015 Volvo V-60
2012 Camry hybrid
1970 Camaro, original owner