I've made some progress with the front hubs this week. I've drawn up the adaptors that I need made up. These are based on the adaptors that are posted on http://www.ricola.co.uk/ (follow the links to 'My Car > Speedster > Suspsension + Running Gear > Brakes). The hubs and brakes used for the mods to the speedster are early 944 units, he also uses Drum type spindles. The link to the adaptors are at the bottom of the page.
As I am using later hubs and calipers (from a 944 Turbo) the adaptor dimensions are different. I did a bit of searching to see if I could find bearings that had the same Inner Diameter as the VW units and the same Outer Diameter as the Porsche Hub but could not find any. I did however find a seal that will fit both the Porsche hub and the VW spindle. (I will update this post when I return to work next week as the details are on my desk).
The dimensions you can see on the pics have been taken from the Porsche hubs and the VW bearings that I have, The first image is the outer adaptor and the second the inner.
The strange tolerances are to allow the bearing adaptor and the bearing to be a press fit.
I would advise that if you want to do this mod yourself, make sure you measure the hub and bearings that you intend to use as they may be different from the dimensions here (I'm not sure what changes there were in sizes over the years - the Porsche hubs obviously changed as the dimensions stated on http://www.ricola.co.uk/ are a lot different to mine).
The other thing to be carefull of is the 1mm thickness under the bearings - this sets the hub offset relative to the spindle - too little and the discs will rub on the spindle casting, too much and the overall track will increase.
The bearing adaptors should hopefully be finished by next week which will then allow me to fit the hubs and start work on designing the caliper adaptors. I will post the drawings for these when I have finished.
For anyone who is interested in the package that I use for these 3D designs - it's free and is called Sketch Up. You can download it from http://www.sketchup.com/ The pro version allows for a frew extra features but the normal version is more than adequate for design realisation and also produces drawings suitable for manufacture. I originally downloaded it to design the extension for our house (shown in progress below), I then decided to use it for sketching up some parts for the car. I'd reccomend viewing the instructional videos they have on the site.
You can download the models of the rear suspension adaptors from the downloads page.
