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Solving a Hub and Spindle Mystery: Part 1
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ideola  



Joined: 01 Oct 2004
Posts: 15501
Location: Woodstock IL

PostPosted: Fri Oct 31, 2008 8:16 am    Post subject: Solving a Hub and Spindle Mystery: Part 1 Reply with quote

OK, Rasta, here's a chance for you to flex your PET muscles.

I need some help with this. I have three different styles of front hubs, all from various makes of 944's. Here is what they look like:
  • The one on the left is stamped 477.405.605.D and comes from ???
  • The one in the middle is stamped 951.341.605.00 and comes from a 1986 951
  • The one on the right has no stamping and comes from a 1987 944S

I'm confused by a few things. The version of PET that I have shows ALL the hub numbers for 944's from 1983-1990 as ending in 065 regardless of the prefix. The parts are stamped ending in 605. So it looks like PET has a typo.

Moreover, the diagrams in PET do NOT depict the style of hub that is photographed on the right, and yet I have multiple sets of these. What is concerning is that the rotor for this hub is completely different than the rotors for the other two. The first two hubs mount in FRONT of the rotor as depicted in PET. But the hub on the right has the rotor mounted in front of it (rather than behind). Unfortunately, I don't have a correct rotor lying around to illustrate the hub on the right, but you can see by looking at the design closely that there is no way for the rotor to mount behind this hub, as with the other two. PET does not have an illustration that corresponds to this hub. Here's a photo to illustrate:


The hub on the left is a standard 944 hub, designed to take normal five lug rotors. The hub in the middle takes a MASSIVE rotor that is not only deeper but also larger in diameter, such that it can accommodate the Brembo 4-pot calipers. This brings into question three things about the hub on the right:
  1. What type of rotor can it use? They necessarily MUST be different than the rotors displayed above because the rotor can't bolt to the back of the hub, but must slip over the front of the hub, similar to how rear rotors are setup. Are there multiple styles of compatible rotors, both in terms of thickness and diameter? This leads to the next question:
  2. What type of calipers is it compatible with? Can either the floating or the fixed style caliper be used? Or are these hubs only compatible with one style of caliper? It's hard to nail down because PET doesn't necessarily show you combinations, and these hubs aren't stamped with a part number to begin with.
  3. What is the resulting offset when everything is bolted up?


Once we have the answers to Part 1, I'll post Part 2 of the mystery.
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15 981 GTS | 88 924S SE | 82 931 Holbert | 82 931 Rallye | 81 937 | 81 Euro 931 | 81 Weissach | 80 US 928 | 80 US 931 '941' | 80 US 931 | 80 931 GTR | 79 Sebring | 78 D-Prod Replica | 78 w/D-Prod kit | 78 Poli-Form | 78 Limited Edition | 77 Martini
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Rasta Monsta  



Joined: 12 Jul 2006
Posts: 11354
Location: PacNW

PostPosted: Fri Oct 31, 2008 8:46 am    Post subject: Reply with quote

As you surmised, PET has the wrong number or those castings are all stamped wrong.

The number 477 405 065 comes back as a front hub to the following apps:
  • Early 924 M471 & GT.
  • 81+ 931.
  • Early 944, through 86.
Also as you surmised, the second setup with thick rotor and thin hub are from a 87 and later 944/951/968 M030/758 brake setup. The distance from the wheel mounting surface to the spindle would be the same. . .the Brembo setup allows a thick rotor without disturbing the offset.

I'm bettting the one on the right is a 928 part. . .there doesn't appear to be any toofah progeny that didn't have the hub setup in front of the rotor.
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Last edited by Rasta Monsta on Fri Oct 31, 2008 9:01 am; edited 2 times in total
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ideola  



Joined: 01 Oct 2004
Posts: 15501
Location: Woodstock IL

PostPosted: Fri Oct 31, 2008 8:56 am    Post subject: Reply with quote

By splined, do you mean in the interior of the center? If so, the answer is no. I know that one came from a 87 944, one from an 87 944S, and one from an 89 944 w/ABS, the fourth one I don't know but it looks identical to the first two. The one from the 89 w/ABS of course has the ABS ring on the exterior of the hub.

So no, the one on the right does not come from a 928. I know this for certain. What I'm puzzling over is the rotor and caliper arrangement, as I don't have any examples to look at, PET illustrations are not helpful, and I'm not about to order a set of rotors just to find out
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15 981 GTS | 88 924S SE | 82 931 Holbert | 82 931 Rallye | 81 937 | 81 Euro 931 | 81 Weissach | 80 US 928 | 80 US 931 '941' | 80 US 931 | 80 931 GTR | 79 Sebring | 78 D-Prod Replica | 78 w/D-Prod kit | 78 Poli-Form | 78 Limited Edition | 77 Martini
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ideola  



Joined: 01 Oct 2004
Posts: 15501
Location: Woodstock IL

PostPosted: Fri Oct 31, 2008 9:26 am    Post subject: Reply with quote

Actually, looking at your response Rasta, I think the second setup is NOT what you've identified. The middle piece DEFINITELY came from an 86 951, which PET says is 951.341.065.00, same number (almost) that is tamped on the hub itself (951.341.605.00).

Also, I know for a fact the hub on the right came from 87 944's, which PET says is 951.341.605.00. The M030 option is listed as 951.341.605.08.

Where it gets really confusing is trying to sort out the brake options. There are 477, 951, and 928 part numbers all listed.

The real point of this post is two-fold:
1. What is the offset of the hub on the right?
2. What calipers and rotors are compatible with the hub on the right?
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15 981 GTS | 88 924S SE | 82 931 Holbert | 82 931 Rallye | 81 937 | 81 Euro 931 | 81 Weissach | 80 US 928 | 80 US 931 '941' | 80 US 931 | 80 931 GTR | 79 Sebring | 78 D-Prod Replica | 78 w/D-Prod kit | 78 Poli-Form | 78 Limited Edition | 77 Martini
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Rasta Monsta  



Joined: 12 Jul 2006
Posts: 11354
Location: PacNW

PostPosted: Fri Oct 31, 2008 9:50 am    Post subject: Reply with quote

To clarify, hubs don't have offsets. Are you really asking "what wheel offset will work with these hubs and 'X' fender?"
  • 924 M471/924S Offset was 52.3 (steel control arms, narrow fenders "late offset").
  • CGT Offset was 23.3 (wider fenders, "early offset").
  • Early 944 offset was 23.3 (steel control arms, "early offset")
  • Post 87 944 offset was 52.3 (longer control arms, "late offset")
  • Post 88 951 offset was 66 (long arms, wider 7" wheel)

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ideola  



Joined: 01 Oct 2004
Posts: 15501
Location: Woodstock IL

PostPosted: Fri Oct 31, 2008 10:02 am    Post subject: Reply with quote

Well, the reason I asked about the offset relative to the hubs is because the post-87 hub is clearly several mm shorter than the other two. Because I don't have a rotor for this setup, it's not clear to me where the back side of the wheel mounting face would be, but it's prettly clear that it would stick out a few mm farther than the earlier stuff. Seems to me this affects offset. But then again, all this stuff confuses me
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15 981 GTS | 88 924S SE | 82 931 Holbert | 82 931 Rallye | 81 937 | 81 Euro 931 | 81 Weissach | 80 US 928 | 80 US 931 '941' | 80 US 931 | 80 931 GTR | 79 Sebring | 78 D-Prod Replica | 78 w/D-Prod kit | 78 Poli-Form | 78 Limited Edition | 77 Martini
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Rasta Monsta  



Joined: 12 Jul 2006
Posts: 11354
Location: PacNW

PostPosted: Fri Oct 31, 2008 10:12 am    Post subject: Reply with quote

Well, color me baffled, nothing in the steering or brakes sections of PET is consistent with Mystery Hub.
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ic932  



Joined: 11 Feb 2005
Posts: 1104
Location: UK

PostPosted: Fri Oct 31, 2008 10:25 am    Post subject: Reply with quote

perhaps i can help solve the mystery. from 87' (regardless of 944 model) the front discs are mounted on the outside of the hubs and secured with 2 grub screws.....like most "modern cars".
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ideola  



Joined: 01 Oct 2004
Posts: 15501
Location: Woodstock IL

PostPosted: Fri Oct 31, 2008 10:39 am    Post subject: Reply with quote

ic932 wrote:
perhaps i can help solve the mystery. from 87' (regardless of 944 model) the front discs are mounted on the outside of the hubs and secured with 2 grub screws.....like most "modern cars".

But what brake rotors and calipers are OK to use? Clearly the same rotors used for the other two won't work. So different rotors are required. But what does that mean relative to calipers? I need to make sure the set of calipers I'm sending to the boys down under will work with everything else.
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15 981 GTS | 88 924S SE | 82 931 Holbert | 82 931 Rallye | 81 937 | 81 Euro 931 | 81 Weissach | 80 US 928 | 80 US 931 '941' | 80 US 931 | 80 931 GTR | 79 Sebring | 78 D-Prod Replica | 78 w/D-Prod kit | 78 Poli-Form | 78 Limited Edition | 77 Martini
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ic932  



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PostPosted: Fri Oct 31, 2008 10:59 am    Post subject: Reply with quote

any 944 cast iron caliper will work. like you say, they are 944S parts. and they only came with bog standard cast iron calipers.

all cars with brembo calipers (S2&TURBO) will have 951...cast into the hubs.

did you take a good look at the spindles? 86 turbo and 87- all have a different (bigger) bolt hole spacing for the struts. i'm not sure that the later hubs can be used on early spindles?
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ideola  



Joined: 01 Oct 2004
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Location: Woodstock IL

PostPosted: Fri Oct 31, 2008 11:39 am    Post subject: Reply with quote

The hubs and spindles all appear to be interchangeable. I have three different types of spindles and three different types of hubs, and they are all interchangeable. I'll have to check the strut housing bolt-up...that's a new one I haven't uncovered elsewhere.
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15 981 GTS | 88 924S SE | 82 931 Holbert | 82 931 Rallye | 81 937 | 81 Euro 931 | 81 Weissach | 80 US 928 | 80 US 931 '941' | 80 US 931 | 80 931 GTR | 79 Sebring | 78 D-Prod Replica | 78 w/D-Prod kit | 78 Poli-Form | 78 Limited Edition | 77 Martini
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ic932  



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PostPosted: Sun Nov 02, 2008 5:57 am    Post subject: Reply with quote

i stripped down and compared an early 944 hub/spindle/disc assembly with a late one.

the later spindle is way thicker so there is absoulutly no chance of interchanging hubs!

to answer your question, if you want to use the hub on the right of your picture (87'944S) first you will need the correct spindle and the later style disc (top-hat style). luckily any cast iron 944 floating caliper will do. but unfortunatly you will need the later 944 struts to fit the spindles.

wheel offset will depend totally on what WHEEL/WISHBONE COMBINATION you use.
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ideola  



Joined: 01 Oct 2004
Posts: 15501
Location: Woodstock IL

PostPosted: Sun Nov 02, 2008 6:57 am    Post subject: Reply with quote

So then the hub on the right and the hub in the middle are both interchangeable with the early spindles?

I'm not sure what you're getting at though, because I have three styles of hubs and four styles of spindles, and they all appear to be interchangeable. The struts, yes, the bolt pattern is different on the later spindles, I did confirm that. I need to get early spindles anyway because the boys down under need the speedo holes. But now it's a matter of making sure I can pair up the correct hubs. I have enough of each style to make it work, but I want to make sure I get them the best alternative without depleting my stock for what I need...

Time to go back into the garage and do some more double checking. And actually, that is the second part of the mystery...I have a mystery spindle and set of front calipers that is unlike any of the others. I'll photograph and post it later on.
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15 981 GTS | 88 924S SE | 82 931 Holbert | 82 931 Rallye | 81 937 | 81 Euro 931 | 81 Weissach | 80 US 928 | 80 US 931 '941' | 80 US 931 | 80 931 GTR | 79 Sebring | 78 D-Prod Replica | 78 w/D-Prod kit | 78 Poli-Form | 78 Limited Edition | 77 Martini
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ic932  



Joined: 11 Feb 2005
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Location: UK

PostPosted: Sun Nov 02, 2008 8:12 am    Post subject: Reply with quote

no, the early spindles require early hubs...end of story. these can be sourced from all 931's and 944's up to mid 85ish.

take the time to compare the spindles (knuckles) you have, pick the one with the thickest "spindle" (the part the hub slips over) it becomes very clear that the early hubs (the ones the guy's in oz need) won't fit. or you could take time to pick the knuckle with the thinest spindle and attempt to fit one of the late hubs to it...guess what, it's a very lose fit!


"So then the hub on the right and the hub in the middle are both interchangeable with the early spindles? "

mate, it sounds like your confused about this stuff. if this is the case is it really a good idea to offer such critical parts for sale!
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ideola  



Joined: 01 Oct 2004
Posts: 15501
Location: Woodstock IL

PostPosted: Sun Nov 02, 2008 8:20 am    Post subject: Reply with quote

Dude, I'm not offering parts for sale, I'm doing these guys a huge favor just by pulling all the stuff together. This is exactly why I posted, to make sure that if I go to all the trouble to pull this stuff together, and they go to the trouble to pay for the ocean freight, that they get the right stuff. And by the way, try finding this information anywhere on this forum or elsewhere. What I've learned thru this process is that there are many more permutations than what the FAQ and various other posts would seem to indicate on first read. So at the end of this effort, we should be able to have a definitive reference for what will and will not work, along with any caveats.

I appreciate your input though, this is the first time I've collected all this stuff together in all the various permutations. Maybe the issue here is that I don't have an "early" hub, i.e. one from a 931 or a pre-85.5 944. I'll get out the dial calipers and measure what spindles I do have on the bench. In the meantime, I've already put out some calls to see about swapping the late spindles and hubs for early ones.
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15 981 GTS | 88 924S SE | 82 931 Holbert | 82 931 Rallye | 81 937 | 81 Euro 931 | 81 Weissach | 80 US 928 | 80 US 931 '941' | 80 US 931 | 80 931 GTR | 79 Sebring | 78 D-Prod Replica | 78 w/D-Prod kit | 78 Poli-Form | 78 Limited Edition | 77 Martini
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