RSR 73 Replica Front hubs for 930 brakes

[CJMRSR]

In the final stages of setting up my front wheels to front fenders and have run into a slight issue.I have 1985 930 brakes and 930 hubs and 9x15 genuine Porsche wheels with ET3 offset and it's throwing the wheel out roughly 1 inch too far. Is there a different front hub I can use that's narrower but still use my 930 rotor and calipers? Or should the wheel arch but wide enough to accommodate my current setup?

[CJMRSR]

[Bill Verburg]

Originally Posted by CJMRSR

In the final stages of setting up my front wheels to front fenders and have run into a slight issue.I have 1985 930 brakes and 930 hubs and 9x15 genuine Porsche wheels with ET3 offset and it's throwing the wheel out roughly 1 inch too far. Is there a different front hub I can use that's narrower but still use my 930 rotor and calipers? Or should the wheel arch but wide enough to accommodate my current setup?

yes, just remove the 930 rotor and hub and replace the hub w/ a '72-89 911 hub and a '78/79 930 rotor and hat assembly.

the oe '78/79 930 rotor assembly consists of an annulus an 2 rings held together w/ t locks to enable the float.

These are available and Elephant has their own version of this







There used to be simpler more modern annulus + hat + McLaren spring loaded bolts but I don't know where to get this version today. Possibly Willwood

The advantage of this later simpler setup is less rattling

[CJMRSR]

Originally Posted by Bill Verburg

yes, just remove the 930 rotor and hub and replace the hub w/ a '72-89 911 hub and a '78/79 930 rotor and hat assembly.

the oe '78/79 930 rotor assembly consists of an annulus an 2 rings held together w/ t locks to enable the float.

These are available and Elephant has their own version of this







There used to be simpler more modern annulus + hat + McLaren spring loaded bolts but I don't know where to get this version today. Possibly Willwood

The advantage of this later simpler setup is less rattling

Thanks Bill. So the 78'79 930 rotors are compatible with the later 85 calipers? I presumed they are just double checking.

Do you know what hubs came on the original 73 RSR's? Just want to check my fenders are not the issue, ie they are wide enough.?

I will check with Willwood and others to see if they do the simpler option.

[Bill Verburg]

Originally Posted by CJMRSR

Thanks Bill. So the 78'79 930 rotors are compatible with the later 85 calipers? .

yes

Originally Posted by CJMRSR

Do you know what hubs came on the original 73 RSR's? on.

regular '73 911 hubs which are the same through '89. The 9" ET3 wheels were designed for these hubs

the 930s changed to the 1 piece rotor 1/2 way through 1980. The '80 up 930 hub pokes 21mm further out than the 911 hub, so the spacers were discarded. These are designed for Fuch 7ET23.3 or 8ET23.3 wheels.

[gled49]

78-79 turbos used a 1” wheel spacer with the front hub. Later turbos incorporated the wheel spacer into the hub, like you have, not allowing 9” wheel fitment.

[dannobee]

I can see those are not later model 930 hubs. On the '81 and up hubs the access to the allen bolt is through a hole drilled into the hub at the widest diameter. Looking at the last pic you can see the notch for the allen key at the edge of the hub's dust cap surface at the 3 o'clock position.

Later model 930 front hubs look like this.

https://www.parts-wise.com/93034106501-485337/

There are a few different sized 911 hubs with various spacing. Look here.

https://forums.pelicanparts.com/porsche-911-technical-forum/473760-can-anyone-confirm-front-wheel-hub-depth-67-vs-later.html

But are you sure that the wheels are sticking out too far?

https://pbase.com/slidevalve911rsr/image/52667194

Also, there are two different sized hubs taking two different sized grease caps, 58mm and 72mm. See post #18 here.

https://forums.pelicanparts.com/porsche-911-technical-forum/1098829-front-wheel-bearing-inspecting-parts-questions.html#post11412501

[Bill Verburg]

Here's a comparison of the '78 -79 and the '80 up 930 setup. A '73 RSR would have used the same configuration as the '78 -78 w/o the 21mm spacer


VCI used to sell the simpler floating system using he McClaren spring loaded bolts, the 911 hubs and flat hat


here's a similar Coleman 930 setup

[CJMRSR]

Originally Posted by dannobee

I can see those are not later model 930 hubs. On the '81 and up hubs the access to the allen bolt is through a hole drilled into the hub at the widest diameter. Looking at the last pic you can see the notch for the allen key at the edge of the hub's dust cap surface at the 3 o'clock position.

Later model 930 front hubs look like this.

https://www.parts-wise.com/93034106501-485337/

There are a few different sized 911 hubs with various spacing. Look here.

https://forums.pelicanparts.com/porsche-911-technical-forum/473760-can-anyone-confirm-front-wheel-hub-depth-67-vs-later.html

But are you sure that the wheels are sticking out too far?

https://pbase.com/slidevalve911rsr/image/52667194

Also, there are two different sized hubs taking two different sized grease caps, 58mm and 72mm. See post #18 here.

https://forums.pelicanparts.com/porsche-911-technical-forum/1098829-front-wheel-bearing-inspecting-parts-questions.html#post11412501

It looks like my shop has mocked it up using a non 930 hub, I will check with them tomorrow.
I am going to see the car in a couple of weeks so I will assess then if the wheels are too far outboard. Some of the photos are quite deceptive with the lighting.
Thanks for your reply and the info.

[CJMRSR]

Originally Posted by Bill Verburg

Here's a comparison of the '78 -79 and the '80 up 930 setup. A '73 RSR would have used the same configuration as the '78 -78 w/o the 21mm spacer


VCI used to sell the simpler floating system using he McClaren spring loaded bolts, the 911 hubs and flat hat


here's a similar Coleman 930 setup

Thanks Bill, that's exactly what I needed to see to get my head around it. I will look and see who is selling an appropriate set up, at least I can maintain the 930 caliper up front to match the rear.

[Bill Verburg]

Originally Posted by CJMRSR

It looks like my shop has mocked it up using a non 930 hub, I will check with them tomorrow.
I am going to see the car in a couple of weeks so I will assess then if the wheels are too far outboard. Some of the photos are quite deceptive with the lighting.
Thanks for your reply and the info.

They must be quite creative to use a 911 hub w/ a late 930 rotor
here's a an '80 up 930 rotor and hub, the hub gas a built-in 21mm spacer and the rotor has a built in 21mm counter spacer to move it back to fit the caliper






compare that to the flat '78/79 rotor, which used the 911 hub and a separate removeable spacer to move just the wheel 21mm out.

[CJMRSR]

Originally Posted by Bill Verburg

They must be quite creative to use a 911 hub w/ a late 930 rotor
here's a an '80 up 930 rotor and hub, the hub gas a built-in 21mm spacer and the rotor has a built in 21mm counter spacer to move it back to fit the caliper






compare that to the flat '78/79 rotor, which used the 911 hub and a separate removeable spacer to move just the wheel 21mm out.

Thanks Bill, I do like the 911 hub w/ a late 930 rotor hub solution with the counter spacer. Do you know who did this?

I have found elephant racing do a hat kit adaptor, they have a floating and non floating option. Not sure what the difference is as they would both be connected to the rotor and the hub..
I couldn't find anything else that solves this apart from the original Porsche parts for the 78-80 930 set up but they soon add up in price.

[Bill Verburg]

Originally Posted by CJMRSR

Thanks Bill, I do like the 911 hub w/ a late 930 rotor hub solution with the counter spacer. Do you know who did this?

I have found elephant racing do a hat kit adaptor, they have a floating and non floating option. Not sure what the difference is as they would both be connected to the rotor and the hub..
I couldn't find anything else that solves this apart from the original Porsche parts for the 78-80 930 set up but they soon add up in price.

The one piece rotors above are factory '80 up 930. They cannot be used w/ the 911 hubs

As i understand it you issue is that the front 9ET3 pokes too far outboard. The most likely cause is the late 930 hub. switch to a911 hub which does not push the wheel outboard.

to use a 930 size 32x304mm rotor w/ the 911 hub you need a flat rotor annulus w/ a flat hat, factory 3 piece/ t-slot '78-79 are 1 option. The 2 Elephant appear to be another though I am unfamiliar w/ them. As long as they are designed for regular 911 hubs they will be fine.

floating are very desirable for a track car due to the high temperatures generated, the high and variable temps cause a lot of expansion and contraction which combined w/ their holey nature lead to premature cracking of the rotor. The downside on t-slots is the extra noise generated around town. Mclaren developed a spring loaded bolt that allows float and doesn't contribute to noise issues.

some installations are also 2 piece but the parts are bolted solidly together.

Just a guess but the Elephants are likely offered as solidly bolted or 1 of the 2 above floating designs. Bothe for use on 911 hubs.

To reiterate
930 hubs move the wheel outboard 21mm more than 911 hubs.
the factory 1 piece 930 rotor is only compatible w/ the 930 hub
to get a 32 x304 mm 930 size rotor w/ 911 hubs you need a multipiece design w/ flat rotor and flat hat.
floating is more desirable for track use and as long as noise isn't an issue fine for street use.

[CJMRSR]

Originally Posted by Bill Verburg

The one piece rotors above are factory '80 up 930. They cannot be used w/ the 911 hubs

As i understand it you issue is that the front 9ET3 pokes too far outboard. The most likely cause is the late 930 hub. switch to a911 hub which does not push the wheel outboard.

to use a 930 size 32x304mm rotor w/ the 911 hub you need a flat rotor annulus w/ a flat hat, factory 3 piece/ t-slot '78-79 are 1 option. The 2 Elephant appear to be another though I am unfamiliar w/ them. As long as they are designed for regular 911 hubs they will be fine.

floating are very desirable for a track car due to the high temperatures generated, the high and variable temps cause a lot of expansion and contraction which combined w/ their holey nature lead to premature cracking of the rotor. The downside on t-slots is the extra noise generated around town. Mclaren developed a spring loaded bolt that allows float and doesn't contribute to noise issues.

some installations are also 2 piece but the parts are bolted solidly together.

Just a guess but the Elephants are likely offered as solidly bolted or 1 of the 2 above floating designs. Bothe for use on 911 hubs.

To reiterate
930 hubs move the wheel outboard 21mm more than 911 hubs.
the factory 1 piece 930 rotor is only compatible w/ the 930 hub
to get a 32 x304 mm 930 size rotor w/ 911 hubs you need a multipiece design w/ flat rotor and flat hat.
floating is more desirable for track use and as long as noise isn't an issue fine for street use.

Thanks again Bill. I understand fully what you are saying. I will need the 911 hub with the 930 flat rotor with an appropriate flat hat. Point taken on the floating for track use. It's mainly going to be a street car so I am going to try and get a solution with the McLaren spring loaded bolt.