VDO speedometer, numbers and dates

My RS, build date 4/73, came with 250 km/hr speedometer. According the RS bible of Dr. Konradsheim it should be a 300 km/hr VDO. On the outside are a couple of numbers stamped and the date of manufacturing, 11.72.

Did Porsche stamped the date in it in order to correspond with the build date of the car, or was it VDO and how close should they match ?
The following numbers are on my 250 km/hr speedo:
part. no. 911.641.501.00,
26/30/1 and W=0.5 T. What do they mean, I guess 0.5 has something to do with the calibration and/or tire size.

Is it correct that VDO made different gauges for different tire sizes, like the 50 and 70 series tires ?

Does anybody know the part. no's for the 300 km/hr speedo's for 50 series or 70 series tires, and if they are still available.
How about 60 series.....

Hello

AFIR all RS up to mid september 72 had 250 km/h speedos.

The first 300 km/h speedos had handpaintet dail faces ( I know the speedo from RS 0013 wich had a datestamp from 11/71 ). That was to expensive for massproduction.
Looks like your speedo was swaped.

The date stamp is corresponding to the date when the speedo came in to Porsche and was checked for quality and mostly used in a car within the same week. However sometimes the suplieres worked "ahead" an stocked the approved parts to be used later out of row.

But a observation is that all 5 instruments have datestamps within the same month or just one off.

Porsche had a own speedo for low profile series 50 tires.

Those tires came with the 930 and the 2,7 carrera in 74.

The tiresize isn´t to point the rolldiameter from the tire is relatet to the speedo.

The 0,5 is the Wegzahl. Have to look for a english description as it is a bit complicatet to expalin.

Grüsse

Roland,

I don't know of this helps or not, but my RS #493 has the 300 km/hr speedo. I'm travelling until Sunday, but I can then take it out and email you the part # if you still need it then. BTW, I assume the speedo just twists out like on the newer cars, right?

Rob

According to the RS book, from 3/73 the RS recieved the 300 km speedo. From the early production cars I have seen and from many of the closely examined photographs this seems to be correct. Just look in the RS book for example, and you will see several examples of cars with the 250km speedo. A keen eye will notice that the placement of the resting needle and the 50km indication are in a different location than on the 300km speedo, all of the markings on the 300km gauge are rotated around in a clockwise direction about 15 degrees with the 300km mark at the bottom. Page 99,105, 152, 185, all show the 250km gauge in the RS, and this is one book alone. Many other books show the same thing. For reference I just finished a inspection of chassis 861 a March production car and it had the 300km gauge proven original to the car without question. But chassis 250 is owned by a friend of mine and it has a 250km gauge original to the car. From all of the published factory info that I have in addition to the cars that I have seen and all of the carefully inspected photos in many books, it should be obvious that the early RS production cars came with the 250km gauge which at some point was replaced by the 300km gauge at a time frame of around march or april sounds correct. You being in april may be a gray area.

The part number for the gauge as is seen on the face of the gauge at the top is 911.641.503.00. This part number is also the same in the parts manuals and is no longer available. Another variation of this gauge is the 911.641.503.04 which is used on the 74 and on Euro carrera which is also 300km but has a different needle without the silver button, other than that it is identical. I have seen several poorly silk screened examples of this gauge which is the quality of work you would see from a refinished silk screened face that several gauge rebuilders would produce. It may look OK to most but not to the fussy eye. I have never seen any of these non production gauges in any car where its authenticity could be proven, and to me it looks like a reprodution that I have seen so many times. I did see a 300km gauge in a 70 ST chassis number 1138 I think and it was a non production version with marginal guality workmanship, but its originality to this car could not be proven and to me looked like a reproduction.

Oeps, what a couple of numbers can do! Let me add some more. My RS is # 1410, originally Italian delivery and rides on 7 and 8J x 15 rims, 205/55/15 front and 225/50/15 at the rear. The 0.5 Wegzahl (I understand, ich bin Hollander) should be ok for this size.
On the other hand, going back to originality, I will still try get a 300 km/hr speedo. Wolfturbo, how about a swap.....

I will take a closer look at the other cauges and see what date is stamped in it. Sofar many thanks, Roland, Schmidt and Wolfturbo.

Hey Cees, leuk je hier aan te treffen! (sorry, Dutch for saying "hi" on the board).

Tom