275/40/20 tyres

Hi all, new here, thought the title may grab , own a t5.1 you can see him on instagram #jeanclaudevancamper . any way im here because of wheels and tyres, right , my van has 20" bebb alloys , 8.5j , dont know offset...came with the van from , its a t28 converted to a camper. standard suspension...

Well, put the wheels on tonight with the 275/40/20 tyres, and all went well, little bit of rub on the engine cover underneath at the edges....any ideas on how to fix it....... Here is a close up, As i say the only issue is full lock, touches the side of the lower engine cover, which...