they'll fit but it will be suspension and tire size dependent.
You can run a 245/35/18 square setup if you install camber plates up front (highly recommended modification for the 1 series anyway), and then a 245 will fit in the rear with an inner fender roll. it might still rub on very hard bumps, but a lot of setups out there rub.
Here's a photo of a 235/40/18 NT-05 on an 18x8.5" et38 APEX ARC-8 wheel front and rear. Without going into detail. a 245/35 will have less, or at least more predictable issues vs the 235/40 we tested. It's WAY taller then the stock 215's for the front. and even taller then the oem rears. But technically you could run 235 all around as well, or even 225, but that's not really an upgrade.. It's all debatable...
