Rep Power: 286

I bought another pair of 17s for my car. As I look around the site. Some people have 215/45/17s and some have 205/40/17s. What size is better for our cars? Also I know the 215/45/17s on my old wheels didn't affect the speedometer. Would the 205s differ?

 
Rep Power: 288

yes. not significantly, try checking out a tire calculator to get somewhat exact measurements. so why not stick with what works?

 
Rep Power: 276

http://www.eunos.com/tirecalc/tirecalcold.html