Bought a set of 4 for my 2002 Honda Civic Si. The size of the studs on my car is 4x100. It was just what I needed when I bought a set of spare wheels and snow tires. The new steel wheels I bought didn't match my hubs. 5mm is the exact thickness to solve this problem on my car, but don't stick out so much that it looks like a Super Mario Cart. The fit of the spacers was ok. They are universal so I wasn't expecting an exact fit. I mounted the wheels on spacers, tightened the nuts, and cruisedβ¦