On Saturday, October 28, 2017 at 8:13:26 PM UTC-7, Frank Krygowski wrote:
On 10/28/2017 9:11 PM, John B. wrote:
On Sat, 28 Oct 2017 16:59:47 -0700 (PDT), jbeattie
wrote:

On Saturday, October 28, 2017 at 3:40:36 PM UTC-7, AMuzi wrote:
On 10/28/2017 4:27 PM, jbeattie wrote:
On Saturday, October 28, 2017 at 12:08:44 PM UTC-7, Sir Ridesalot wrote:
On Saturday, October 28, 2017 at 11:09:18 AM UTC-4, Joerg wrote:
On 2017-10-27 17:11, John B. wrote:
On Fri, 27 Oct 2017 06:58:27 -0700, Joerg
wrote:

On 2017-10-27 01:11, John B. wrote:
On Wed, 25 Oct 2017 07:53:11 -0700, Joerg
wrote:

On 2017-10-24 17:21, John B. wrote:
On Tue, 24 Oct 2017 11:47:12 -0700, Joerg
wrote:

On 2017-10-24 07:27, wrote:
On Tuesday, October 24, 2017 at 2:19:48 AM UTC-7, John B. wrote:
On Mon, 23 Oct 2017 10:09:20 -0700, Jeff Liebermann
wrote:

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.

Undoubtedly so. But if the advantage of "carbon" bikes can be
extolled that a carbon-carbon frame must have twice the bragging
rights :-)


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

Given the coefficient of friction between a 1.25" wide rubber tire
(32mm) and a wet road probably dragging the feet will work.. :-)

Joerg's experience is with full suspension MTB's. These things are
incredibly heavy and long wheelbased. He has his judgement of disks
and it is no doubt quite accurate for his experience and riding.

I have disks on a much lighter and shorter wheelbased bike. I know
the failings up close and personal. I simply cannot imagine WHY a
person would want a more complicated system than that offered by the
Campy Skeleton brakes.


The reason can be summed up in one word: Rain :-)

But last Sunday I started out my "weekend" ride in the rain. It had
been raining nearly all night and the roads had a lot of water on them
- note we have been having floods here in Bangkok lately - but it
appeared that the rain was ending so off I went.

Unfortunately my weather forecasting facility wasn't working very well
and I rode 20 Km of a 30 Km ride in light rain and flooded roads in
many places. I was splashing through water in some places and cars
were splashing through (and splashing me) in others.

Of course, Sunday is much lighter traffic then on work days but still,
Bangkok is rated as one of the cities with the most chaotic traffic
in the world, and I did have to stop suddenly several time, on flooded
roads with wet wheels and brakes.

My brakes worked just as they do in the dry. Back brake stops me
somewhat slowly and front brake stops rather suddenly, both brakes
together provides best stopping. No long wait after grabbing a brake
lever although I did think of you with your stopping problems and I
have the feeling that the brake lever pressure might be a tiny bit
more to stop in the rain but if it was it was so little that it
couldn't be quantified.

But of course I am using quality brake pads. Why it costs me US$12.12
a wheel just for pads alone.... but they do last a year or more.


It seems Californian rain and Thai rain aren't the same. When it rains
heavily and I have to do a surprise emergency stop after not having used
the brakes for a while there is 1-2sec of nada, absolutely nothing. It
makes no difference whatsoever whether I use $17 high-falutin Koolstop
rain-rated pads or $4 Clarks pads. The experience of other riders around
here and in this NG is similar.

Which, to be honest, I find a little mystifying as I've had pretty
constant success with conventional brakes.

Frankly, I can't believe this is solely because I'm somehow so
uniquely skilled or that y'all are all in the awkward squad

I do see a number of people here and many who are not here who seem to
have ridden for years using conventional brakes without complaint and
some of the blogs I read don't even talk about brakes. Dave Moulton,
for example. An old fellow, used to race bikes, came to the U.S.. in
about 1979 and built frames commercially for years, now retired, has
one entry in his blog about brakes - "centering side pull brakes".

Another blog from the long distance side of the bicycleing world, The
Blayleys, who are into Audex's and who apparently each ride in the
neighborhood of 10,000 miles annually, mentions Vee brakes in
reference to a Tandem while a photo of them on a tandem on their web
page shows disc brakes. On the other hand, when she discusses a "good
brevet bike she simply says that the "brakes must clear the fenders
and probably long reach caliper brakes will suffice".

In short, it seems that brakes just don't seem to be a hot subject in
much of the cycling fraternity.


To a large part that is because most cyclist will not ride in driving
rain. Some do and those know exactly how that delay with rim brakes
feels. Occasionally it is called "free fall" because that's how it feels
like.

Well, the Blayleys state that the husband, John, has ridden 10 - 17
thousand miles a year for the past 25 years and the wife, Pamela, has
ridden from 10 - 14 thousand miles a year for the past 20 years, or
another way to put it might be that together they have ridden from 20
- 30 thousand miles a year for the past 20 years.

Somehow I suspect that they may have encountered rain in that period.


And grandpa has driven his cars without safety belts yet survived ....

For people who do not shy away from unpaved roads or use a lot of
singletrack and ride in the rain there is a much more extreme issue: Wet
mud. You may have never encountered it but I have many times. You reach
in and, after a second or two of nothing, the rim brakes come on but let
off an awful grinding noise. You can literally hear the rim being
tortured but because of a rapidly approaching curve you can't let go. As
I have mentioned before the rims on my old MTB are only 1000mi old but
the front rim is almost shot from all that. Deep grooves.

I stand by my opinion that rim brakes are fair weather brakes. Then they
are fine but not when the going gets tough. Like this kind of weather:

https://www.youtube.com/watch?v=mX_EKybzK4Y


I might comment that I've ridden coaster brakes, drum brakes, rod pull
brakes, cantilever brakes, side pull single pivot caliper brakes,
double pivot caliper, Vee brakes and for one short ride a cable disc
brake. and at the time I rode them I found all the brakes to give
acceptable service. Well with one exception, rim brakes and chrome
plated steel rims were sometimes a bit iffy :-)


Yes, those were the worst. It got a little better with aluminum rims but
not a lot. In the world of automotive such a brake "system" would not
stand the slightest change of being legal.

Finally after many decades the bicycle industry woke up and adopted what
the automotive guys had all along, disc brakes. Why should I accept an
inferior brake system on a new bike when there is a much better one?

Well, when I worked on airplanes I remember that the F-4 had multi
plate disc brakes which provided a tremendous amount of stopping power
in a very small package.


Some tandems have that as well, and of course motorcycles: Two discs up
front. But not stacks of discs.


One supposes that will be next big improvement in bicycle brakes. Or
perhaps a drag chute for those long downhill's to keep the rims from
melting?


I've thought about it :-)

--
Regards, Joerg

http://www.analogconsultants.com/

Oh ****! I've ridden many hundreds of miles off road in dry and wet sand, mud, heavy rain, rutted roads/trails and did so on an MTB with cantilever brakes and NEVER had trouble stopping either when I needed to or when I wanted too. I've ridden on ice and in 4 inches+ deep snowand also never had trouble stopping.

Perhaps you ride too fast for the conditions/sight lines or you don't keep your brakes adjusted properly.

Really? I have trouble standing up on ice. There is a point at which you don't want super-strong brakes.

-- Jay Beattie.


Yeah me too.
Snow is one thing - I'm used to that- but ice is quite
another. Depending on the recent weather, a frozen slick
patch of ice under snow will dump me right on my ass. We
mere humans would have some trouble with Jobst's famous tour
down a frozen Swiss river.

I live at a whopping 400 feet (about) elevation. The garage in my building is probably 0 feet. That minor elevation change sometimes means the difference between ice and no ice -- so I walk outside in the morning and say f*** this! And then I jump in the car and half-way to work, creeping along in traffic, there is no ice -- and then I regret not riding. So, in order to avoid that regret, I have done some pretty stupid sh** spinning around on ice or hoofing it in my SPDs to get out of my neighborhood and then being freaked out riding over the slick bridges and viaducts into town. I met up with another guy on a bike who was fish-tailing down the road on one of those mornings, and we looked at each other and shook our heads -- "we're a couple of idiots." So, now I'm working on not feeling regret or guilt if I drive. And don't get me going about the dopes who jump into their Malibus with no-season/no-tread tires and crash on the ice and/or snow. I'll slap on the snow tires in
November. I really miss studs, but I'm doing penance with studless.

-- Jay Beattie.

Are studded auto tires legal? I seem to remember that back in the
1960's when I was in Maine that it was illegal to drive studded tires
on bare roads. It was a long time ago and memory is always
questionable but I'm sure that I remember people getting a ticket for
using studded tires under certain conditions.

I don't know if they're legal in Oregon now (Jay can tell us) but I've
driven out there in the summer and experienced the weirdness of a
freeway with two troughs worn in it by thousands of studded tires.

Our cars track (i.e. left to right wheel span) didn't quite match the
trough widths, and our car had a disturbing tendency to "hunt" back and
forth as I drove.

Studs are still legal. https://www.tripcheck.com/Pages/Chain-Law#

-- Jay Beattie.