On Sunday, October 8, 2017 at 5:05:32 PM UTC-7, James wrote:
On 07/10/17 00:51, wrote:
On Thursday, October 5, 2017 at 6:37:10 PM UTC-7, James wrote:
On 06/10/17 09:41, jbeattie wrote:


All one piece rotors I know of are SS, although you can buy CF
rotors. Magura (and I think Avid) makes thick rotors (2mm) that
are supposed to be good at shedding heat, but I don't know of
anyone who makes them thicker than that. You'll have to do some
detective work.



I wouldn't have guessed that slightly thicker rotors would be
appreciably better at "shedding heat".

On MTB's on difficult descents the rotors are almost red-hot. Since
I've never seen rims that hot I can only assume that the disks allow
you to hang it out a lot further.


Since bicycle rims have enormous cooling surface area compared to a disc
rotor, it is obvious why they don't get so hot yet can still provide
adequate braking performance.

And let's face it, aluminium tends to phase change from solid to liquid
without appearing "red hot".

--
JS

And the modern bicycle rim is very likely to be 30 mm deep or deeper for aero purposes. Lots of material and with a very low coefficient of conduction.