First and foremost: suspension before wheels.
Secondly: build your wheels around your car, not your car around your wheels.
All MKVs are 5x112.
VW center bore is 57.1mm.
Mercedes center bore is 66.6mm.
Factory tire sizes: 225/40/18, 225/45/17, 205/55/16.
Tire Size Conversion
195mm = 7.67"
205mm = 8.07"
215mm = 8.46"
225mm = 8.85"
Tire Size Breakdown
215 is the width of the tire.
40 is the height of the side wall.
18 is the size of the wheel.
45 series tires on 17" wheels.
40 series tires on 18" wheels.
35 series tires on 19" wheels.
OE Wheel Listing
Charlestons: 18x7.5 ET51
Classix: 17x7 ET54
Detroits: 18x7.5 ET51
Huffs: 18x7.5 ET51
Interlagos: 18x8 ET41
Karthoums: 18x8 ET51
Omanyts: 18x7.5 ET51
What will fit?
18x8.5 ET45 with 215/40/18s is the ideal fitment for a MKV is without camber or fender work.
18x8.5 ET35 with 215/40/18s is the most flush fitment without much effort. Front fenders will need rolled and pulled.
Offset is a measure of how far the hub mounting surface is from the center of the barrel. A positive offset indicates that it is further toward the face of the wheel, and a negative offset indicates that it's behind the center of the barrel.
Offsets on MKVs can vary from ET30 to ET50 without much alteration to the car/suspension.
Spacers are used to do exactly what the term sounds like... space out the wheels.
If you run a 20mm spacer on your wheels that are ET51, your new offset will be ET31 as you are pushing the center of the wheel further away from the hub.
Ball seat lug bolts for OEM wheels.
Conical seat lug bolts for AFTERMARKET wheels.
Stock thread pitch is 14x1.5mm
Stock head size is 17mm
Stock lug bolt length is 27mm.