If I change the stock tires and wheels on my Infiniti M35x from 18" (aspect 45) to 20" (aspect 35), handling should improve but will the ride be significantly harsher? The change is mainly cosmetic and I don’t want to ruin a good ride…this is my wife’s car.
Yes, the ride will be significantly harsher–both for the passengers and for the vehicle’s wheels and suspension components. Unless you drive on velvety-smooth roads, you can anticipate a high likelihood of bent wheels and prematurely worn-out ball joints from the impact of potholes.
I live where potholes are a way of life. I would not have those things on my car for any reason. Of course I would not have them if they did not increase the chance of damage, I feel they look like some silly teenager thing or someone trying to relive their teens.
why would handling improve? in what way?
Thank you for your advice. I am getting a clear picture that I should not consider this change. With regard to cappy208’s question…I have read that shorter, stronger, sidewalls result in more precise turning ability. This may or may not be true. More importantly to me is the information that VDCdriver provided. Scary.
Handling is theoretically improved a bit because of less sidewall flex (what sidewall? 
) and the ride will be harsher because of less sidewall movement.
I wholeheartedly agree with the others about forgetting this idea. There is so little cushion in the sidewall of those tires that wheel rims will take a severe beating. Every pothole is a potential wheel cracker.
While going into a local mall a year or so ago I saw a “riced out” Nissan parked in the lot and it was fitted with “rubber band tires” as they call them. This car was tastefully done though (black on black) and from a distance looked really good. As I walked by it I saw that all 4 wheel rims on this car were literally beat all to hxxx even though the rest of the car was immaculate. The wheel rims were marred badly and had nicks/hunks out of them completely around the circumference of all 4 wheels.
Personally, I’m not even a fan of 45 series tires and I certainly would not go less than a 45. JMHO anyway.
Thanks ok4450. I appreciate your evaluation.
I’ve got an idea! How about using regular steel wheels with normal sized tires (65 or bigger), and having a plastic hubcap that “overhangs” the inner part of the sidewall to make it look like you’ve got alloy wheels and low profile “rubber band” tires? Best of both worlds!
I doubt that small a wheel would actually clear the brake caliper of that particular vehicle.