5-Lug Vented Rotors on Rear, Some Questions Options

[Spoke]

The next project for my 914 is converting to 5-lug suspension. I have the front struts and rear hub from a 1972 911 to start with.

The rear will have vented rotors. I have some questions about doing this part of the conversion.

Two questions:
1) Will I need longer studs in the rear? Before adding the spacer, a lug would catch with 11 rotations on a stud. After adding the spacer, a lug catches with only 8 rotations.

2) When I add the spacer, the rotor is no longer centered perfectly on the hub. How do I center the rotor on the hub?


911 Hub



Hub with spacer



Hub with spacer and rotor. 911 rotor has been cut by Eric Shea. Thanks E.



With the spacer, the lug only catches with 8 revolutions, down from 11 in its stock state. Is this enough or do I need longer studs?



With the spacer, the rotor lip that centers it on the hub now misses the hub because of the spacer. How do I center the rotor now? Do I use just the 2 little hold-on screws to center?



One of the calipers that will be used.

[Jeff Hail]

Are those SC or Carrera rear rotors? Looks like the latter by the pics. Doesn't look like the pads are going to fit in there.

[Spoke]

Are those SC or Carrera rear rotors? Looks like the latter by the pics. Doesn't look like the pads are going to fit in there.

SC as Eric mentioned. I got the rotors from Eric and I was able to coax him to cut the rotor diameter to size. I couldn't find a shop around me who would do that. (IMG:style_emoticons/default/dry.gif)

On final install, the pads fit very nicely. Had a little issue getting the adjusters to pop out (it was over a year since the calipers were restored).

The one thing that I didn't like and still don't about the vented rotor adaptation is the rotor itself is not self centered now.

Because the spacer goes between the rotor and hub, the rotor no longer contacts the edge of the hub and loses the centering.

The mounting screws hold the rotor in place but do not provide very good centering. There's still a lot of play in the rotor concentricisity. I used a run-out gauge to center the rotors then tightened the rotors with the mounting screws.