you should be safe with a 40 series tire, thats pretty thin. but i remember having trouble with the inner plastic lining in the wheel well when i had my 17's on 205-40's in my cr-ex. but as long as your springs keep their bound and rebound. and shocks are in good shape you should be fine. i would have some conscern if you had like a 3" drop or more.but should be fine.