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Old October 23rd 17, 04:51 AM posted to rec.bicycles.tech
Jeff Liebermann
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Posts: 4,018
Default Why do some forks and frames have brake rotor size limits?

On Mon, 23 Oct 2017 07:02:08 +0700, John B.
wrote:

But re disc brake cooling F1 car brakes appear to work with the discs
red hot. In the 1,000 degree (F) range. And they use Carbon Fiber
discs too :-) And everyone knows that CF is better.


"Thermal Conductivity of Carbon Fiber, and other Carbon Based
Materials"
http://www.christinedemerchant.com/carbon_characteristics_heat_conductivity.html
"So...Is Carbon Fiber a good heat conductor?
As usual the answer is "it depends." The short answer is NO
not when regular carbon fiber is made up in regular epoxy
and expected to conduct heat across the thickness. IF a
highly carbonized pan fiber with graphite or diamond added,
is measured for heat transmission in the length of the fiber
it is very good and can rival and exceed copper."

Ah, diamond disk brakes, surely the next big thing. It would also be
interesting to see if breaking a few carbon fibers causes a hot spot
on the disk or belches black smoke.

Thermal Conductivity in W/(m.K)
Diamond 1000
Silver 406
Copper 385
Aluminum 250
Carbon Steel 54
CF and Epoxy 24
Quartz 3
Pyrex Glass 1
Concrete 0.4 - 0.7
Plywood 0.13
Pine 0.12
Air 0.024

Hmmm... 92.5% sterling silver disk brakes. Not as good as diamond,
but better than CF.


--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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