Advice on Disc's

[Barry]

BMW repair manual says 4.6mm min thickness.  They are only 5.1mm when new.

[HESIMEUSTIC]

No changes are needed for the EBC rotors .

There are different rotors for the twin shock R65's, the snowflake wheel needs a deeper dish hub than the LS version, the snowflake wheel is narrower than an LS wheel at the hub .

If I have 1979 w. snowflake wheels and twin shocks at the back then I'm looking at deep dish replacements?  I just noticed I have a radial crack in my original rotor and am trying to figure out a replacement for it now  :-/

[fbenach]

Thank you for the info guys, I will surely be thinking about this EBC semi floating units when the time come.

[steve hawkins]

Yes,  Radial cracks are a 'no, no'.  Standard r65 discs are what they call 'deep dish' whereas the older/larger airheads are shallow - as they either go 5 rib hub for a laced wheel, or a wider snowflake.  They were meant for ATE swinging calipers.....

A 3 rib front hub can be sourced to put a laced front wheel on an R65, the slimmer hub was require to give clearance to the more normal ATE/Brembo brakes fitted to the R65 and later post 81 airheads.

Rev light

[GeoffSmith]

Chris, I cannot comment on your disc's as I am no expert, I changed the ones on my R65LS because I had read that they can crack across the holes, so I changed them for solid cast iron ones, my view is that the solid cast iron ones do not brake quite as good as the originals and they do start to rust after being out in the rain. I hope you get some expert advice back to your mesage, all the best Geoff UK.