Are wheel spacers safe? Does the wheel spacer you use matter? What is hub centric? Today I will show how you how to install wheel spacers properly and safely. We will be installing 10mm Spacers in the front of my MK7.5 and 15mm Spacers on the rear. In addition to the right spacers, we look at using the proper length wheel bolts when installing spacers. Also using the proper bolts for the wheels you are using Conical Seat bolts or Ball Seat bolts.