Big mistake going from a 235/45 to 235/40?
 

Just bought new wheels and now I am thinking about shoes for them. My current stock set is 235/45R18 on 8-inch wide Sport wheels and I am going up to 19x8.5 with a 45 ET. I am thinking of staying with the 235 size to be safe,but thinking of going to a lower profile tire (235/40R19).Will a thinner sidewall make that much of a difference, as far as ride quality (4.2" versus 3.7"?) and most importantly, will the wife notice the ride quality right away? Thanks,HB

Yes, the shorter side wall will give your car a ride quality which will be noticeably harsher and wheel damage will be much more likely as well. And due to the greater rotational mass of the 19" wheels, your car will also suffer a slight reduction on fuel economy, slightly reduced acceleration and braking abilities and the only thing you end up with is a "look".