Hokie1200

To fit HRE's made for a C240 to my C230 Sport (front), 5mm H&R car-specific spacers were added along with 30mm wheel bolts. At 40+mph, I get slight vibration in the front. I am assuming for now that the wheels and tire balance are fine.

The 30mm bolts (dull silver) seem to have a more shallow tapered head compared to the HRE-supplied bolts (shiny silver). Also, the 30mm bolts engage the hub 1-2mm less than the OEM bolts even though they should have 1-2mm more depth.

Are there different tapered head specs available?
Can this slight difference be the cause of the vibration?

Hokie1200

I traced the picture of the bolts. The HRE bolt has a 60 degree bolt-to-head angle. The 30mm bolts have a 55 degree angle. This would mean a slight gap between the bottom of the wheel's bolt seat and the lugbolt. Also, the bolt shaft would not engage the hub as deep. Is this 5 degree difference enough to cause vibration or will I be fighting the spacer once the lugbolt is corrected?

Hokie1200

I got 27mm bolts from HRE with a 60 degree head angle. Vibration in the front was greatly reduced, but at 60 mph+ I got some minor vibration. Then I remembered the wheels/tires were balanced without the metal valve caps. Took those off and vibration is gone. Crossing my fingers that 75 mph is not a problem.