What's the bmw 4 series steering wheel size?

The steering wheel size of the BMW 4 Series, at least, for recent model years and going by the 430i, is going to be 14 and a 1/2 inches in diameter with a grip of 3 and 3/4 inches. If You're replacing this, You can expect upwards of $200, and You're going to need to have this professionally installed, because the airbag's going to need to be properly set in (and progRammed). If You're just grabbing some steering wheel covers, You can usually find some quality ones for under $30 that add a bit of a retrofit to Your Bimmer; plus, the leather ones sure do feel nice on cold mornings!