19-07-12, 12:09 PM
I would (and do) use A4 s/s bolts on the rear and would feel less comfortable about using them on the front.
Temperature considerations are not the issue: the rear does only a fraction of the work of the fronts so the slightly better conduction to the bolts is not a significant factor.
Shear strength is what matters. Most readily available s/s bolts have a thread that extends all the way up to the head of the bolt whereas the OEM bolts have a plain shank of a depth that matches the disc thickness. So the replacement bolts are effectively a smaller diameter.
Back-of-an-envelope calculations suggest that there is still a big safety margin for the rear, particularly since braking forces there are relatively small compared to the fronts. Even so, and despite the fact that the braking loads are shared across the two front discs, I'd err on the side of caution and stick to OEM bolts at that end.
http://foc-u.co.uk/index.php/topic,2361.msg18102.html
Temperature considerations are not the issue: the rear does only a fraction of the work of the fronts so the slightly better conduction to the bolts is not a significant factor.
Shear strength is what matters. Most readily available s/s bolts have a thread that extends all the way up to the head of the bolt whereas the OEM bolts have a plain shank of a depth that matches the disc thickness. So the replacement bolts are effectively a smaller diameter.
Back-of-an-envelope calculations suggest that there is still a big safety margin for the rear, particularly since braking forces there are relatively small compared to the fronts. Even so, and despite the fact that the braking loads are shared across the two front discs, I'd err on the side of caution and stick to OEM bolts at that end.
http://foc-u.co.uk/index.php/topic,2361.msg18102.html