Hi there all you experts. I would like to know the difference in hat size of the 1972 914/4 rotors. Before my car was mine, it belonged to a former(retired) co worker. He wanted me to restore his brakes, front and rear. He bought the parts and the first set wouldn't fit on the spindle(deep hat), the second set, the caliper wouldn't bolt up. So he ended up getting the rotor resurfaced. Are there 3 types of rotors for the 914/4 and if there are, what differentiates the rotors and what are the dimensions of said rotors. Asking for a friend...

IIRC, early ('70 ~ '72) brake systems are different than late ('73 ~ '76). They changed the calipers to dual bleeders and rotors became hub-centric instead of lug-centric. It's possible your friend purchased late rotors or someone changed to late struts or even later 911 struts which took 3.5" bolt spacing calipers

I was going to change to late calipers and rotors on my '71, but ultimately decided to stick with the original spec components to avoid any misunderstanding when ordering replacement parts.

I’m pretty sure there was a mid year rotor.

Mark is correct. There were 3 types of rotors. There was a mid 72 year rotor. There are only two types of rotors available though. The early style rotors came from the VW Type 3 for 70-72. Mid 72 had early offset with hub centric center, 73- up rotors and brakes came from the VW Type 4.

I appreciate that fellas. Does anyone know the dimensions of the different rotors? Then maybe I can explain to the parts people what the correct rotor for my car.

Something to consider is that "correct" doesn't always mean "available".

I would ask those more aware for an actual Part No for the unique mid year or consider swapping over to a more available set up.

Best bet is to upgrade to 73 on struts because of the hub centric rotor.

early rotors 70-72 through id number 4722919032. late rotor 72-76 starting with id number 4722919033. SO very late 1972 models starting using the late rotors and pads, but actually the late 72 models had the late offset but not the centering disc for the hub centric mounting of the wheel

My thanks to the doctor...