Wider tire on narrow rim has excess tire roll and loose slight tread contact and tire will roll more in cornering,
Wider rim with narrower tire will make a stiffer sidewall.

They are pushing 285 on stock rims just a hair over reccomended (9.5 - 11 for a 285) yes it fits but will roll tire more in cornering , 305/30 is max size that will fit but 10.5" + rim is needed (305/30 - 10.5 - 11.5).
I thinking about getting tsw bathurst 19x10.5 and can be perfect for 275 I running now (275/35 - 9-11 width rim) and can run wider for my summer tires if I want.