924Board.org

[Juho]

So im thinking of what i could machine now that i have acess to manual lathe and first thing came to my mind that front and rear hubs. Ive designed hubs for our fsae car and i dont think designing these would be a problem. Ive never done machining on a lathe, just some simple stuff like straightening parts but i have people who could teach me that are professional machinists. ive tried to source 5 lug parts for over a year no but no luck so making my own would not seem so bad idea. Only problem i see atm is that the bearing contact surfaces have to be really tight tolerances, probaly talking 0-0.03 and that i cant fea analyze these hubs because we dont know what kind of forces our suspension bears.

[Juho]

these are for bmw and look soo good

[kondzi]

Well, I assume you need also a mill to make it perfect
Idea is good IMHO, I have a manual lathe for a year or so. You can get very precise when using DRO or an analogue / digital dial indicator attached to the not moving part of the lathe pressing against the part that moves.

I'm still learning the proces though and certainly good tooling (knives with inserts) makes life easier.

Having in mind the stock hubs are from cast whatever type of aluminum, if you source a proper 6061 or so for that purpose it would be strong enough IMHO.

On the other hand, aluminum got damn expensive recently...
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Konrad
'89 951 US
'88 Mustang 5.0 LX Convertible (factory specs)
'84 911 Carrera 3.2 RoW (factory specs)
'81 931 RoW (TBD)
'81 Ford Capri 2.8i (factory specs)
'79 Ford Capri 2.9 (heavily modded)

[F3ARED]

Interested in this as Ill need 5 stud hubs for my car and being in Australia, i suspect that wont be cheap nor easy. Racers Edge do make the front hubs from billet aluminium but at $680USD PER HUB its not really a cost effective solution.

Does anyone know where to locate or have a proper dimensioned drawing of the front and/or rear hubs?
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1977 Porsche 924
1987 Range Rover Classic 3.5L V8

[kondzi]

[F3ARED]

Given that the 4 stud hub is integral to the disc and the 5stud hub is separate to the disc, i dont think measuring it will provide anything useful other than bearing OD as i believe the hat heights are different which allows for some of the track width difference between 924 and 944 - i could be wrong on that though. Having the dimensions of the original 5stud hubs would help as no prototyping would be needed; im not trying to reinvent the wheel here, i just want to be able to convert my car to 5stud cost and time effectively. Parts arent necessarily easy nor cheap to obtain for these cars in Oz - being able to get a machinist to turn up some hubs would be fair easier and not too dissimilar in cost as finding OEM hubs and freighting them to australia.

As far as REs hubs go, Im sure they have their reasoning for pricing them at that price - this isnt, and wasnt intended as a slight on them or their product. What I am merely stating is that at almost 2500USD freighted, and after tax, its put simply not a viable option for me.
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1977 Porsche 924
1987 Range Rover Classic 3.5L V8

[kondzi]

I’m sure there was a thread with all the offsets, diameters and so on for 5 stud conversion and options/differences over generations. Search for it then.
I had to turn my front 5-stud hubs anyway for my brake upgrade (search for my resurrection thread - the green 931). With a custom hub why not aim for better disk brake rotors as well…
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Konrad
'89 951 US
'88 Mustang 5.0 LX Convertible (factory specs)
'84 911 Carrera 3.2 RoW (factory specs)
'81 931 RoW (TBD)
'81 Ford Capri 2.8i (factory specs)
'79 Ford Capri 2.9 (heavily modded)

[Mike9311]

Is the idea here that you want 5 lug conversion option in billet?

I have made hubs before but not this type. Its also important to 'bore' the bearing housings so they are truly round. A lathe can do this but a mill needs a boring head.

kondzi is right, Aluminum prices jumped like crazy. I always thought of making some after seeing the racers edge version but now I am wondering about the aluminum cost. I have watched them on Ebay and their price has risen in the past.

I'm going to check just out of curiosity. Might be surprised to learn the 680 might be reasonable


These were made a long time ago and there are some overkill features. I was cnc mill happy. For a lightweight NA (the 80 in my sig) using Honda civic wheels because they were light and cheap at the time. Not only did the hubs save weight, the disc and hub matched the inertia of the original iron disc which is hard to achieve with the larger diameter disc. Eventually I was going to convert the rear as well to disc.








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1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car

[F3ARED]

The idea is to have a means of completing a 5 stud conversion; unfortunately we dont have the luxury of a huge amount of wrecks down here as low volume, good weather and relatively high prices mean the rate of attrition in Porsches is actually quite low, so finding a wrecked 944 to steal the hubs from isnt easy or cheap. It can be difficult with regards to importing used parts too given that Australia has now added asbestos testing as a requirement to importing automotive related things [long story]. In an ideal world, itd be a matter of just following the tried and tested route of sourcing a used 931/944/951 hub and then going 911 disc, brembos etc but unless I get lucky and trip over the required parts, its unlikely to happen.

It never occurred to me to use a 2 piece rotor and mount the rotor to the newly machined hub like you did. I take it you used the standard 4 stud hub for the required dimensions [in which way kodzi would be correct in saying just measured the old hub]?
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1977 Porsche 924
1987 Range Rover Classic 3.5L V8

[Mike9311]

This was much more complicated in my case because I was switching to a Honda Civic bolt pattern and offset as well as a Wilwood calipers.

I didn't have scanning ability in those days so everything was modeled in wood, MDF (cheap dense fiber board), and plastic. I was also wanting to use the 4-lug spindle which is smaller than the 5-lug.

I also wanted to have a full floating rotor instead of bolt on but never finished that part

It should be easier to make a 5 lug hub if you have a hub to take measurements
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car

[Mike9311]

A caliper adapter was also needed. Which for whatever reason at the time, I decided to make them complicated to have fun with new software and the CNC. Bottom pic. The mount holes still needed to be made larger. Imagine the caliper adapters were first made with plywood and glue, the plastic, then aluminum. They should be around and I will take a pic of those as well.

I should add that this setup saved something like -20lbs per side which is crazy light-weighting. The suspension has less work to do

Original quote from my other thread "Even with the new temporary adapters the savings is -8lbs at each side at the rear! This is now close to -40lbs off the front end unsprung and another -16lbs off the rear. All hardware included in the comparison.

-56 lbs (US) of unsprung weight removed total."






_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car

[kondzi]

Wow!
_________________
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Konrad
'89 951 US
'88 Mustang 5.0 LX Convertible (factory specs)
'84 911 Carrera 3.2 RoW (factory specs)
'81 931 RoW (TBD)
'81 Ford Capri 2.8i (factory specs)
'79 Ford Capri 2.9 (heavily modded)

[Euro924S2]

I've made billet front hubs, and twinned them with Jaguar XK8R 300mm discs with 944S2 calipers. That was fairly straight forward, but the rears are a PITA because milling the driveshaft splines is tricky. I resorted to buying a pair of brake drums off Machine7.co.uk which can be ordered blank - ie with no wheel bolt pattern drilled. I then machined off the drum material to leave just a central hub which I drilled to the 5x114.3 PCD pattern I wanted for my jap forged wheels and then used the front brake rotors off a Fiat Ducato 'transit' van as they are the same size as the 944S2 rear discs, but have a lower offset so the calipers bolt up nicely, but the wheel offset could be accommodated.

My advice would be to either pick your wheels and then make everything fit, or
look what's easy to get in Oz and get wheels which work with that setup!


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UK spec '83 N/A with 931 motor with Eaton MP62 'charger @ 15psi. EFI - 565cc inj. Standalone Adaptronic ECU. 951 FMIC. Ally rad. Twin throttle. Recirc valve. Custom manifolds and CAI. 232bhp

[F3ARED]

Mike mate, your work is amazing.

Euro924S2 - Like i said i havent really gone into it too far given that my preference is still to get factory hubs to make life easier. Ideally id like to stick to Porsche wheels/sizes etc so may be a touch more limited in that regard. Sounds like you set the rear discs up to be floating disc [ie over hub and not bolted] - have you got photos of the rear hub once modified, and how did you go about getting the handbrake to work? Had a quick look at the link you sent but couldnt find the blank hubs

Probably should mention engineering requirements down here mean I must have a working mechanical handbrake...
_________________
1977 Porsche 924
1987 Range Rover Classic 3.5L V8

[F3ARED]

Scratch that - found them. Its these hubs I take it? https://www.machine7.com/product.php?xProd=1655&xSec=992

Interesting to know what the height of the drum hub is vs a 931 hub + disc
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1977 Porsche 924
1987 Range Rover Classic 3.5L V8