All this talk about D-90 and CS wheels has got me thinking:
It looks like with a milling machine I can easily convert my flatdish wheels into CS wheels (not a big fan of those stick-on fake thingys). They would look better (IMHO) and be slightly lighter. Has anyone tried this?

 

... and would offer better venting to cool the brakes?

I wonder what this might cost to have done?

My 2 sets of dish wheels are BORING.

 

I persued this path with a most capable machine/competition engine building shop - to get a second set of 'CS' wheels: It is feasible, as the orriginal slots in the flat dish and the 'D's of the CS wheels are machined - so cut a little more ...
To do this, one has to configure the curve to program the cutting arc of a CAM table. It is recommended to take a first pass ~1/4" shy of the final pass so the fly cutter will not force chips into the face (marring the surface) on the 'dress' cut. The edges would then need to be radiused - and the cut surfaces protected against oxidation. My quoted cost was $100/wheel for the machining, leaving me the final two steps - not bad, really.
This proposed cut is how the CS wheels were made, and by examining the reverse face, easy to verify that the reinforced web is not comprimised.
Having said all that, I found a 17" set of BBS wheels , but still believe the idea to be a sound one.

 

Perhaps we could do it as a "group buy". Once a machine shop did all the set-up work, they should be able to do a bunch for cheaper. Anyone else interested?

Garth, was your machine shop in Nova Scotia?

-Victor

 

Excellent idea Victor!
CS wheels are rare so this is one way to replace them cheaply. I never realised the moulding detail was the same. Note that the dish wheels are cast whereas the CS ones are forged but that's probably not too significant to most people.

Colin 89GT (with CS wheels)

 

Good idea.

Who knows, you just may have come up with a crafty way to increase the value & demand of the unwanted/unloved/abundant dish wheels.

 

I am now just kinda waiting to hear one of the resident experts drop by and say "no - you will ruin the structural integrity of the wheels".

Haven't heard it yet, though.

 

All The S and S-4 flat wheels are forged. The club sport 89 GT wheel forged BUT 1990> GT wheels are cast design 90 wheels. All the Porsche 17 wheels are cast. Mark Anderson many years ago made some this way and I believe Devek has offered it as a service. Much of he desirability of the CS ,89 GT wheels is the 8 inch front and 9 inch rear widths.

 

Not long ago someone was selling flats converted to CS wheels on ebay.

 

You can't do this, you will destroy the structural integrity of the wheels.

Am I a resident expert now?

I know of a 928 that has 10" wide phone dial's on the rear. It has been this way for at least 10 years now - holding up fine. The car recently changed hands and I tried to buy those wheels, but the new owner wouldn't sell.

 

They are both boring, IMHO. Stock 928 wheels are a yawner.

 

Jim has already cover the point: all the flat dish wheels are forged - the fundamental difference with the CS wheels other than differing widths and ETs is that less material was machined away from the final forging.
The flat dish is structurally a superior wheel to many cast units - but, as many view it, the appearance is lacking: When set side by side, it is amazing how much the CS wheels improve the 'look' of the car - but that is a subjective area.

Yes, the $ I mentioned were for a local shop: were there any distance involved, two way shipping etc has to be factored. Still, an interesting idea ....

 

I stand corrected on forged/cast . Thanks.

Adam "They are both boring, IMHO. Stock 928 wheels are a yawner". Each to his own. In my book stock rocks.

Colin 89GT

 

yeah but at 16lbs a peice, they would wake up a bit of acceleration.
I still kick my self for selling my CS's. Adam B has them on his car now.

 

Not since he added big reds to his car.

If they were available in seventeens I'd buy a set for track days.

But would really like to get a set of these for the 5sp: