GT backing plates

[Joris Koning]

All,

Trying to make sense of the GT/Spyder backing plates. Hoping that some of you might be able to help by posting pictures of known original plates. Curious to learn the progression from riveted scoops and screens to soldered and spot welded ones.

TIA,

JK

[Dick Roth]

Factory Carrera backing plate. Front

RR

[Joris Koning]

Richard,

Thanks for the picture.

What I am interesting in pin pointing is the change from riveted scoops and screens to spot welded ones. I have NOS A GT rear backing plate in my collection and it has the spot welded scoops. A set of B GT backing plates I have are the same.

I have a set of pictures of a set of RSK/RS60 drums which were offered to me years ago and they have riveted scoops and screens. The supposed 550 drums on this page also have the rivets https://specialtycarsservicecenter.com/ ... storation/ Find it hard to believe that they would have differentiated construction between the Spyder and production cars.

Another interesting question is when the 60mm drums were first officially offered on production cars?

[Dick Roth]

Joris, Happy New Year! I am always very intrested in the subject of arcane parts and the specialized components, especially for RSK's and GT's, since I owned both over time. I have not yet studied your photographs in great detail, But I did have one thought and that was the possibility that some of these backing plates were converted from standard to racing types with the ventilation and the scoops by hand, individually by the factory, or others... That might account for the rivets unless you are aware that those were a factory product.
More to come after I do a little research... Regards, Richard

[Joris Koning]

Richard,

Best wishes for the new year to you also.

I just remembered that Marco has some great pictures on his site taken from the original slides used for the workshop manual illustrations etc. https://www.elevenparts.com/museum.php#prettyPhoto as you can see the A GT backing plate shown has spot welds.

I will check my RS60 parts book and see if the part number listed there is different from the one in the B book.

Joris

[Dick Roth]

What are really cool are the finned alloy backing plates fitted to the RS 60's and 61's. Carl Thompson at Vasek Polak's place had a set but I never quite coughed up the tariff he was looking for to put them on my RSK...They were works of art in themselves.

[Bil Brown]

Here`s an NOS 356B rear ventilated plate. I have had some early riveted plates in the past, some had a thin 10mm strip of tin spotwelded over the perimeter of the screen.

[Bil Brown]

Here`s a pic of an NOS front ventilated plate for 40mm brakes. Note the riveted tin strip over the screen. It`s obviously an "A" plate........wonder what car this was made for?

[Joris Koning]

Hi Bill,

Thanks for posting, very useful. What makes you conclude that the plate with the riveted screen and scoops was for 40MM brakes?

@Richard, Yes, those plates are very cool. I thought they were mag. A friend got some in a parts stash I helped him find. I was all over them. Still have the fantasy of having some made to use on a cool hot rod but they would need some changing to be usable on a street car.

P.S. If anybody out there has or knows of a pair of RSK front drums please let me know

[Bil Brown]

Joris........the front plate has small standard size wheel cylinder holes, the aluminum spacers for 60mm won`t fit unless they are bored out bigger.

[Bil Brown]

Here`s another odd plate.....with large air intake hole........is it original?? It`s an "A" plate with large holes for the aluminum spacer.

[Joris Koning]

Hi Bill,

Thats interesting. Are you sure about the hole for the wheel cylinder being bigger? My NOS GT plate measures 22MM as do two regular plates I quickly grabbed from the shelves to measure

[Bil Brown]

Joris.....agreed.....standard wheel cylinder holes are 22mm.......holes for 60mm application need to be larger in diameter to fit the aluminum spacers for front 60mm brakes. Here`s a comparison of standard hole on right, enlarged hole for spacers left 26mm.

[Joris Koning]

Bill, had a brainfart, was looking at a rear plate and those off course do not use the spacers

[Dick Roth]

Scan RSK Color WPB83.jpg (621.48 KiB) Viewed 1309 times

Please forgive me if veer a little off course on this discussion, but seeing those RSK brake drums put me in mind of just what amazing performance and stopping power these drums deliver. I was fortunate enough to race my ex-works 1959 RSK Spyder all over the US, and what was most impressive to me was the consistent and unfailing stopping power that these brakes delivered. Short track or long, you could step on that pedal as hard as you possibly can and these brakes would be there every time...