How big is too big?
 

2012 Scion TC, stock 18" rims. I've called like 12 Toyota dealerships to see what size tires i can put on with out effecting drive-ability, nobody in any of the service or parts department has any clue. So here I sit before you.

How large of a tire can I put on my 2012 Scion TC with out effecting drive-ability. I'm old and I don't like the road noise. :rolling:

Please no guesses and no "I heard from a friend". Only looking for real input from actual experience. I know it might be a while before I hear something back.

Thanks in advance for any helpful input.

Why not use the properly sized tire?..