yes, with the 4.0mm hexes, the arms must be shaved when used with some wheels. I always shave my 6.1 Arms before I install them. My bet is that when they designed the new arms, they did not test smaller wheels like the muchmore's on the car. If they are not shaved they rub pretty badly on the ribs at the bottom of the arms. I shave those completely off, being careful to leave them perfectly flat. This helps setting tweak easier.