Brake Rotors for a 1978 R100RS

[jsey]

Hi all
I'm working on my 1978 R100RS and just changed both tires front and rear. The bike has only 10,000 original miles and is still working on the original discs. The question I have is were these originally specified and supplied with as some type of stainless steel?
Can't seem to find information on this anywhere. Thanks

 

[20774]

I can't find anything as well...most of the specs for the period are generic saying just perforated disk(s). On my /7 early on, I decided to change the front disk for some reason...don't remember. I still have the disk sitting at the bottom of my spares pile. It looks good, no rust of any kind, and a magnet sticks to it.

 

[robsryder]

On my 77 R100RS with over 85k miles the rotors were nearing the minimum thickness spec. The rotor specs are found in the service manual (the Vintage BMW club has downloadable manuals on-line).
https://vintagebmw.org/library/?model=R100RS

I obtained EBC rotors for replacement when the front tire needs to be replaced. I found EBC rotors on ebay. Following are links to left and right rotors -

EBC Pro-Lite FRONT LEFT Brake Rotor 1974-1985 BMW R60/R75/R80/R90/R100 MD602LS
https://www.ebay.com/itm/2234607734...3N372p8XZqQmEeDKsKHipr9THGnB|tkp:BFBMoKHL29Vh

EBC Pro-Lite FRONT RIGHT Brake Rotor 1974-1985 BMW R60/R75/R80/R90/R100 MD602RS
https://www.ebay.com/itm/2234659370...lYno41/x6AyCDzf77BF5Ow6o30ZZ|tkp:BFBMoKHL29Vh

 

[stevenrankin]

Discs

I don't recall any specific data regarding the composition of the OM disc brake rotors. I am not quite sure what your question is, LOL, I am sometimes thick headed.

At 10,000 miles, the rotors should have plenty of life in them unless the bike was stored and they rusted solid or caliper froze and they were so hot they warped? LOL I find it hard to believe either of these two things happened.

I replaced my stock OM rotors on my long time high mile bike at just about 100,000 miles. St.

 

[jsey]

Thanks all for your collective help