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Old November 11th 17, 06:47 PM posted to rec.bicycles.tech
Joerg[_2_]
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Default Why do some forks and frames have brake rotor size limits?

On 2017-11-11 08:59, jbeattie wrote:
On Saturday, November 11, 2017 at 8:34:13 AM UTC-8, Frank Krygowski
wrote:
On 11/11/2017 10:37 AM, Joerg wrote:
On 2017-11-11 07:21, jbeattie wrote:

... I don't think most people need discs with giant rotors, but
Joerg is a special case.


All one has to do is go down French Creek Road and then Holly
Drive out here on a loaded bike and the li'l 6-incher in back
starts to smell. Can't use the front too much because it's loose
gravel. Similar for some of the long hills in the Sierra east of
here. The 8" rotors I mounted yesterday will allow me to roll
down many of the long downslopes without a cooling-off break or
spritzing water onto the rotors.

A friend had 8" on the front and still lost the front brake at
the last curve on a long hillside. One of those "Oh s..t!"
experiences.


Hmm. So even 8" isn't sufficient. Good to know.

My brakes are about 25" diameter. I'm keeping them! ;-)


In Joerg's neighborhood but much further into the Sierra, I did
Monitor Pass, Ebbetts, Carson and Luther multiple times on loaded and
unloaded bikes with either single pivot Campy NR or Mafac cantis.
Tioga, too. Ebbets has some 20% pitches. I never once had brake
problems.


Very different scenario because there you can just "let'er rip" most of
the time. I described a road that has a long downhill stretch and is
gravel. You have to hold the brakes the whole time because there is
forest left and right. Sure enough about 70% down a Shepherd and a
smaller dogs came out of the woodwork and were totally unfazed but my
brightly lit aluminum horse. They sauntered across. At 40mph that would
have been a nasty crash. At 15mph I could even greet the dogs properly.
There are also diagonal ruts and washouts that you won't see in time at
high speed. A reminder could be seen in one curve where a car driver
must have thought differently, flew off the road and chopped some trees.
The wreckage was already hauled off but there still was a torn-off front
axle and a ripped out coil spring way out in the bushes. Ghastly.

--
Regards, Joerg

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