Hello.
The rear discs on my 5 have a slight coating of rust towards the center near the hub. Apart from changing the discs is there anything i can do?
paint it with hannerite or smooth right.The temperature will be ok
as long as you dont get it on the swept area you will be ok…
You can do the calipers at the same time!
silver for the OEM look or a brighter colour to stand out from a crowd
Like this. plus the centre hub. 
Do not paint the face that the wheel bolts on to. This may cause wheel nuts to lose pre-load and self diassemble resulting in a risk of death. Also you’ll crash when the wheels fall off.
Ignore it? [;)]
I wouldn’t bother with Hammerite, it just burns off.
[6] ive used engine paint in the past with good results [8-)]
I have just had one of the wheels off my car for an unrelated job and I noticed mine were still covered well with hammerite after wiping the dust off the callipers and discs.
With Goof on this one [:)]