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Old October 23rd 17, 06:09 PM 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 12:48:29 +0700, John B.
wrote:

On Sun, 22 Oct 2017 20:51:15 -0700, Jeff Liebermann
wrote:

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."


On the other hand, they seem to work pretty well :-)
See https://www.youtube.com/watch?v=h5JcHAEmIYM
for a visual indication of heat dissipation. :-)


Impressive. I'll assume it's a carbon-carbon rotor, since all F1 cars
seem to using them.

http://www.racecar-engineering.com/technology-explained/f1-2014-explained-brake-systems/
(4 pages)
"A typical road car uses a cast iron brake disc with an organic
brake pad. In an F1 car, though, the same material is used for
both disc and pad, and this material is known as carbon-carbon
- a significantly different material to the carbon-fibre composites
used in the rest of the car"
In other words, the F1 brakes are NOT made from CF.

Some detail on Formula 1 brakes:
https://www.youtube.com/watch?v=ev6XTdlKElw

Fun destroying brakes:
https://www.youtube.com/watch?v=KslGsXMgmqg
The brake starting at 4:45 sure looks like CF but I'm not sure.

Maybe twin disk brakes would be easier?
http://nuovafaor.it//public/prodotto/75/nccrop/DOPPIO_FRENO_CROSS_ENDURO.jpg
https://i.ytimg.com/vi/Pvwj-WWlKkg/maxresdefault.jpg
https://gzmyu4ma9b-flywheel.netdna-ssl.com/wp-content/uploads/2011/09/Gatorbrake-dual-hydraulic-front-disc-brakes-carbon-rotors01.jpg
https://lh4.googleusercontent.com/-cDfAFWrGR6Q/VHKPsm-f6YI/AAAAAAAAX10/2FCyj87xs0g/s640/14%2520-%25201.jpg
https://www.minibikecraze.co.uk/wp-content/uploads/bs0978.jpg
https://endless-sphere.com/forums/viewtopic.php?f=28&t=56268


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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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