I've got 155/80R13 at the rear. Wanna go 14".. those 165/70R14 are 0.3" bigger in diameter.
I once had quite a few people at the back and it didn't rub though. either 165/65 or 165/70..
175/65R14 is an option too.
By the way, is having 2 different tire width for front and rear a good thing or bad thing for the k11? (Slightly wider at the rear)
I would keep the same tyre sizes both ends to be honest, don't know if the MOT tester would be happy with two sizes (!)
I think you could run them without problems myself, try the bigger ones buddy.
