Rear disk brake conversion question

[teahead]

Rotors from an E24 supposedly works:

http://www.realoem.com/bmw/enUS/par...30CS&mg=34&sg=10&diagId=34_0845&q=34211165252

Realoem says any year from 75-89.

Yet how come many vendors shows rotors for 75-82, and 83-89?

E.g.:

76-82

http://www.ebay.com/itm/BMW-630-633...m53e828e340:m:mXuet6eNN0B1Ra659-4tsmQ&vxp=mtr

83-89

http://www.ebay.com/itm/250848538595?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT

 

[aearch]

why

whats the advantage?

 

[teahead]

whats the advantage?

The advantage of the conversion? Better braking (slightly), less likely to lock up, easier to change pads than shoes.

 

[jmackro]

Yet how come many vendors shows rotors for 75-82, and 83-89?

I don't know the answer to your basic question (which I assume is "what rotors can I use to convert my 2800CS from drums to disks). I had thought the only way to (practically) do this was to substitute 3.0 parts. In that case, isn't the question simply "what rotors fit a 3.0?"

But I do know that the years / part numbers listed on the websites of generic parts suppliers are often incorrect, particularly for older cars. I'd bet that 99% of what they sell is for Asian cars and US trucks built within the past ten years. These people aren't vintage BMW specialists.

 

[aearch]

74

my 74 has disks all around right