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Posted by: gms Apr 13 2014, 08:04 AM

mount up on lathe


Stock version on left


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Posted by: gms Apr 13 2014, 08:05 AM

Stock version on left


Mmmm hub-centric!

Posted by: Eric_Shea Apr 13 2014, 10:47 AM

Took me a while. I was looking for the lathe marks and missed the obvious end of the shaft.

This has tremendous potential. Have you checked rotor offsets? 944?

The 911 rotor will need to be spaced 10mm out and the 914-6 will need 5mm BUT... the 944 rotors may just be the ticket!!

AND... it pulls the offset in another 1/4" plus. Right where we need it!

(Eric exits stage left and scrambles for parts...)

Posted by: SirAndy Apr 13 2014, 10:58 AM

I like that!

I had a set of those 944s at some point, probably lost in space by now (or at McMark's shop).

Posted by: Eric_Shea Apr 13 2014, 11:04 AM

Those are probably a different offset altogether. It would be worth measuring though.

Posted by: Travis Neff Apr 13 2014, 01:03 PM

So 5mm off the backside of the wheel bearing side? Is this so that you don't have to use a spacer, or is there another added benefit.

Posted by: CptTripps Apr 13 2014, 02:25 PM

This is timely. I think I'm fighting what this fixes...

I put my 5-lug rears on yesterday and they're just a LITTLE lose. I was thinking I needed a spacer, but taking 5mm off the back might be easier. I can have a machine shop take that off.


https://www.youtube.com/watch?v=Lw9jVBF2lOQ

Posted by: Luke M Apr 13 2014, 02:48 PM

With the later 5 lug hubs you need to put a spacer between the hub and bearing.
PMS sells the spacers for the later hubs.


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Posted by: Travis Neff Apr 13 2014, 03:04 PM

The worry I have with the spacer is that it pushes out the hub 5mm, which reduces tire clearance (I have my fenders pulled a little bit, and don't want to pull them more running 7's)

Posted by: Eric_Shea Apr 13 2014, 05:06 PM

Doug, you need the hub shaft spacer that Luke suggests. Late model hubs are made for the later 911 bearings which are the same ID size but "thicker" than the early bearings used on 914's and early 911's.

Travis, the spacer doesn't push this hub out any further. The extra 5mm for the later hub came off the backside of the hub. This effectively makes the shaft longer to fit the new bearing, which is what Glenn machined off (the "end" of the shaft). By doing it this way, Glenn has moved the hub face "inward" giving you more tire clearance. If you put the spacer on the hub-centric hub it makes it identical to the early hub.

Again, by machining the end off, Glenn will be moving the face inward and the hub shaft will now fit the early bearing. I'd be willing to bet 944 rotors are the ticket here.

Posted by: jaxdream Apr 13 2014, 05:38 PM

If you pull those hubs you might stand a chance of destroying the wheel bearings . to tighten up put a spacer ( possibly 4-5mm ) on the backside of the stub up against the inner bearing race between the flange of the stub where the cv mounts, other wise source another set of wheel bearings just in case . YMMV.......

Jack

Posted by: CptTripps Apr 14 2014, 09:25 AM

The hubs actually come out relatively easy. (Not just "pull out" but I can get them in/out without the press.)

I've already called PMS about 2 spacers and will see if I can get them here quickly.

Posted by: mskala Apr 14 2014, 09:47 AM

Took me a while to realize this is about modifying a later-model part.

But what is the point of this? Trying to gain 5mm clearance at the expense
of modifying brake mounting?

Posted by: SirAndy Apr 14 2014, 11:40 AM

The point is to have hub centric hubs so you don't have to rely on the wheel studs to center your wheel ...

Posted by: worn Apr 14 2014, 11:45 AM

Is the difference in shaft lengths the reason I had to offset my M calipers when I used a 911 stub? I should have done more reading before assembly.

Posted by: mskala Apr 14 2014, 12:58 PM

However, you already have the studs there, which will center the wheel. I don't see
any mod to the part to make it threaded for using wheel bolts.

Posted by: SirAndy Apr 14 2014, 01:03 PM

You lost me there ... Wheel bolts????


The point is that with even with 5 studs, you're relying on those to center your wheels when tightened and there is a chance that you'll torque down your wheels slightly off center and create a wheel imbalance.

The inner 3 piece ring on the new hub shown in this thread makes sure that the wheel is completely centered. Hub centric they call them for that reason.
That allows for proper wheel fitment every time with now chance of getting them off center.

Posted by: mskala Apr 14 2014, 01:36 PM

The lug nuts are spherical and will center to the studs. So what you're saying is
that Porsche is incapable of producing a hub with properly aligned studs, but it is
totally capable of producing a perfectly aligned ring for centering.

Posted by: mskala Apr 14 2014, 01:42 PM

lug nut


wheel bolt

Posted by: r_towle Apr 14 2014, 02:30 PM

It is quite possible to torque down a wheel offcenter.
Aluminum wheels, steel (bolts or nuts) can grab the wheel in such a way that you can honestly mount them off center, and they bounce like crazy.

I learned all about this with my BMW....with stock wheels....
I jumped up to 7 series which had a center hole 2mm larger....wheel bounced all over the place.

I had to get special adapters, little plastic sleeves that fit over the hub....fixed it.

I mounted those wheels probably 20 times trying to figure this out.
Had them balanced at least 5 times, at three different shops.

Ended up being a 4 dollar little sleeve, all was well.

rich

Posted by: SirAndy Apr 14 2014, 02:32 PM

No, that's you putting words into my mouth


What i'm saying is that after 40+ years, there's a lot of hubs out there with studs that aren't perfectly straight anymore and there's also plenty of wheels that aren't prefect anymore.

I know because i have both of those problems above ...

Posted by: Mike Bellis Apr 14 2014, 04:14 PM

So what year 911 have these hubs that can be milled down 5mm?

Posted by: jaxdream Apr 14 2014, 05:47 PM

Maybe the OP will enlighten us as to the source of those turned down hubs , they do look like 944 / 951 hubs . Could be the reason to turn down, shorten ???


Jack

Posted by: bdstone914 Apr 14 2014, 05:57 PM

911 started using the hub centric hubs in 74. Not sure about using 944 hubs. There are probably more 74 and later hubs than the 69 to 73 hubs that are the desired five lug swap. I think you are also going to need the 74 and later longer stub axle.

Posted by: Eric_Shea Apr 14 2014, 09:47 PM

No. That's because of the vented rotor.

914-6's use a 911 rear hub.

Posted by: Eric_Shea Apr 14 2014, 09:56 PM

Remember, once you do this, the rotor offset will be your biggest challenge. Too busy fighting Cayenne's today to measure the offset of the 944's here.

Posted by: Travis Neff Apr 18 2014, 11:30 PM

Bump.. Looking to hear what rotor and caliper you are going to use