budge96

The wheels in OP are aluminum not magnesium ,and they readily show hub center caps these likely would have been issued on street 3.8RS models of course RSR models usually
We're run with BBS centerlocke some also opted for the much more expensive and lighter
magnesium centerlocke option.
I doubt it was recommended to run the 3.8 bolt ups as centErlocks the mag centers were
Also offered in the Cup car series ..
Ask me where the ones in my avatar came from.. A cup! Bert

cobalt

That's because we are talking different speedlines. The speedlines on the 1994 3.8RS/RSR are the 964 version and only came with aluminum centers. A variation of the same wheel used on the 1994 turbo 3.6. I have some pictures I need to find of several 3.8RSR's that had the speedlines with center hubs.

The sales paperwork states only this

According to Barth's own words and the order forms the factory only offered these wheels on both versions. I would have to assume the BBS's used were done after the cars left the factory just as the magnesium Speedlines on the 962 were not raced due to the large price tag Porsche put on them at the time. So although they too were supplied with speedlines almost all 962's were clad with BBS's for racing but did not come that way from the factory.

The wheels on your car are correct for the 993. They came in three versions one of which had magnesium centers. The ones in the picture I am posting are the mag centered wheels as you can see the centers are completely different but all were made by speedline and carry the speedline for Porsche etch.

I have no doubt the wheels for sale are 1994 3.8RS speedlines.

cobalt

After posting those pictures I noticed that the wheels for sale had been disassembled and reassembled improperly. Look at the valve stem location it is incorrect.

jim dorociak

Anthony - very good eye. Most every 3.6 Turbo wheel that I have disassembled the valve stem sits in opening between two spokes, 180 degrees opposite from the spoke with the metal content casting. jdorociak@gmail.com jim

budge96

I am no guru on this and certainly defer to Jim in most respects but
Am reasonably certain cup cars and 3.8RS could and were supplied
With 3.6 turbo style centers that also were magnesium and center lock.
Also if I'm not mistaken that first shot you posted is my rears with
new Michelin Sports at Jim D's back yard...Bert

jim dorociak

I have never seen a magnesium 3.6 Turbo Speedline center. I have seen a true 9.5 Factory cup center that has the caliper cut on the inside of the rear spokes, but this center has a different manufactured offset and was assembled by Porsche Motorsport for a friend in the UK. There are three different wheels available for the 993 cars (3 piece 18" Speedline 993 RS wheels) - The standard 8 & 10's cast aluminum that are built with 1.25" outer rims front and rear and using 6.5 and 8.5 inner rims 52 ET 8" and 65 ET 10. Next there were the center loc magnesium centers that were 47 ET 8.5 and were 1.25" and 7" and in the rears they were 60 ET 10" and were 1.75" and 8" - and finally the GT2 street version magnesium drilled 5 x 130 with the normal depth for center caps. This wheel I am going to describe fronts were 9": 2.25" and 6.5" rears were 11" but were 3.75 and 7". The magnesium centers weigh approx 4 lbs less than the cast aluminum ones. jdorociak@gmail.com jim

jim dorociak

I remembered one one key identifier of the street GT2 magnesium wheels beside being drilled for 5 x 130 they are built with 30 hole components vs the standard 40 hole rims. Jim jdorociak@gmail.com

budge96

Jim please forgive me dear friend but simply because you never worked on it doesn't mean it doesn't exist .
I'm fairly certain the 964 cup cars ran a mag centered centerlock Speedline on the 3.6T design.
If you look at the photo posted on prior page that I believe is a 3.6T style centerlock center .
Another misnomer in your previous post is " street magnesium centerlock" these were produced as race only not recommended for street .
That's why I believe most cars delivered with them were intended for track non street ,,,
Just my understanding ..Bert

jim dorociak

Bert - I do not think I said there was a GT2 street version magnesium center that was a center lock - if I inferred there was then let me correct the record. I am attaching a picture of a factory GT2 street magnesium that came drilled 5 x 130, has 30 bolt components and has the standard depth where the center cap snaps in. You are right, just because I have not touched a magnesium 3.6 Turbo center does not mean there is not such an animal. I have never seen one and do not remember reading about one. jdorociak@gmail.com Jim

james6speed

Jim D, have you any information regarding the color of the centers for the Magnesium GT2 version? I really like that color the best of the three.

jim dorociak

Well, I could not find a stock color that matched the factory GT2 Street Magnesium paint color, but since I had a factory wheel I had a custom paint match done. In fact I had 3 done and finally settled on the one that I used for the set that went down to Brazil. It was a very difficult match as the paint flopped with the metallics and depending on the light and angle that you were viewing the match it matched, but then did not. I will tell you that I painted another set the color we I had been painting "Stahlgrau" steel gray and that is still one of my favorite colors. The factory GT2 center color actually has some green/golden hues visible. jdorociak@gmail.com jim

james6speed

Thanks for all the info and high res pics of your work. It is nothing short of spectacular what you do. I was originally going to paint my wheels Grauschwarz black grey, because I just couldn’t find the right metallic grey for my RH’s that I feel would look right. All of the gunmetallic type paints that I have seen just don’t cut it for me. After seeing this, I feel confident that the Stahlgrau looks wonderful enough for me to commit to. Especially on Guard’s Red.

cobalt

The reason why Jim has never seen a magnesium centered 3.6T version of the speedline was because it doesn't exist. Only the 993 GT2 version used a mag center. Ironically the mag alloy they used is not your standard aircraft magnesium alloys and actually weighs more per pound than an alloy like AZ91 or any of your rare earth alloys used in today's F1 wheels like ZE41A. By filling in the openings found in the aluminum versions I can't imagine much weight savings was gained. Normally magnesium weighs a third less in this case I doubt the centers weigh that much less than the aluminum's.

BTW Jim I hear you picked up Mikes speedlines?

jim dorociak

Yes they got here on Friday. As I said earlier the used sets are hard to find and expensive anyway that you cut it. As with any 20 year old set they need much work even before a restoration begins. So as it stands now I have a set of Speedline 3.6 Turbo wheels available for a great build, and I have a set of RH wheels available for a special Porsche friend. jdorociak@gmail.com Jim

budge96

Maybe this can help ,more than likely the centerlock 3.6T center on the RS/RSR was mag in 1992
and the 993 RS centers were certainly mag,hell the set on my GT2 came from a Cup car and were
built to GT2 spec,they originaly were 9.5 /10.5.