which size ??

hi everyone,i am looking at getting some bfgoodrich all terrains for ma car,ino they are the tires i want ,and need for what i am doing,but i am undesided on the size,i dont want 265/70 they are too big as i am not lifting my discovery,so i am looking around 245,but how different are they to the size i have now witch are 235/70/16 ??

This is the best tyre size calculator I've found

Custom rims, wheel tire packages for your ride - RIMSnTIRES.com

it looks as if the 245 is not that much bigger than the 235,but i suppose the more rubber you have on the road the more grip and stability ,so thanx for that it has helped,appriciated