Why do some forks and frames have brake rotor size limits?

On Friday, October 27, 2017 at 12:26:49 PM UTC-4, Joerg wrote:
Snipped
Dirt on an MTB is a badge of honor. So far I've never cleaned my MTB
because it'll be dirty again 10 miles later.

http://www.analogconsultants.com/ng/bike/Muddy3.JPG

After a free bike wash due to rain:

http://www.analogconsultants.com/ng/bike/Muddy3.JPG

The remainder is caked in so hard that the soft side of a green-yellow
kitchen sponge won't get it off. The scrub pad of it might but then the
paint job is going to be scuffed and it'll collect dirt like a magnet.

Urban dwellers can buy spray-on dirt so their ride looks more manly. No
kidding.

https://www.theguardian.com/science/2005/jun/14/uknews

--
Regards, Joerg

http://www.analogconsultants.com/

ALWAYS the same photo posted by you.

Dirt left caked on a bicycle is sign of laziness and/or neglect by the bicyclist.

No wonder you have so much trouble with bicycles and related stuff.

The more I read of your posts the more I think you're a really big Usenet Troll.

Cheers

On Friday, October 27, 2017 at 12:31:56 PM UTC-4, Joerg wrote:
Snipped
Many others just don't know any better. I have witnessed several people
riding a bike with hydraulic disc brakes for the first time and the
reaction was usually "WHOA!". Same with me, it almost sent me over the bar.

Snipped

Well, hah hah. I had that EXACT SAME response the first time I braked really hard with my Dura Ace AX brakes on my road bike back around 1984.

In fact with either those brakes, side pulls, cantilever or V-brakes I can just about go over the bar just by using the front brake only hard. Just means YOUI aren't using your brakes properly.

Cheers

On Friday, October 27, 2017 at 5:40:05 PM UTC-4, wrote:
Snipped
Exactly how do you plan ahead for someone opening their door? Especially these days when people will pull over to consult their cell phones and then drive off again? And narrow bike lanes in heavy traffic always brings out the jerk in drivers. Yesterday I was almost hit by two drivers as I was pulling across a three lane into the left turn lane when there was a red light for them and they could see me crossing.

I have so much less problems with long haul truckers who know the rules and know that losing 5 seconds here means nothing.

Rather simple Old Boy. (giggling) You look aheadand if cars are parked right beside your bicycle lane you move left out of the bicycle lane when it's safe to merge into the motor traffic stream. I do that every day.

Cheers

On 2017-10-27 16:15, Sir Ridesalot wrote:
On Friday, October 27, 2017 at 12:26:49 PM UTC-4, Joerg wrote:
Snipped
Dirt on an MTB is a badge of honor. So far I've never cleaned my MTB
because it'll be dirty again 10 miles later.

http://www.analogconsultants.com/ng/bike/Muddy3.JPG

After a free bike wash due to rain:

http://www.analogconsultants.com/ng/bike/Muddy3.JPG

The remainder is caked in so hard that the soft side of a green-yellow
kitchen sponge won't get it off. The scrub pad of it might but then the
paint job is going to be scuffed and it'll collect dirt like a magnet.

Urban dwellers can buy spray-on dirt so their ride looks more manly. No
kidding.

https://www.theguardian.com/science/2005/jun/14/uknews

--
Regards, Joerg

http://www.analogconsultants.com/

ALWAYS the same photo posted by you.


No, sorry, the 2nd link should have been:

http://www.analogconsultants.com/ng/bike/Muddy4.JPG


Dirt left caked on a bicycle is sign of laziness and/or neglect by the bicyclist.


Why? Cleaning an MTB borders on the nonsensical because it takes just a
few miles intio the next ride and it looks as dirty as before the wash.


No wonder you have so much trouble with bicycles and related stuff.


Important stuff is very well maintained here and also checklisted before
rides. Such as brakes, chain, lights, battery charge level, fork and
rear shock air pressures, and so on.

Appearance is simply ... unimportant. To me.


The more I read of your posts the more I think you're a really big Usenet Troll.


Well, think what you want.

--
Regards, Joerg

http://www.analogconsultants.com/

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.




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.

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?

--
Cheers,

John B.

On Fri, 27 Oct 2017 06:59:56 -0700, Joerg
wrote:

On 2017-10-26 17:16, John B. wrote:
On Thu, 26 Oct 2017 17:08:10 -0400, Radey Shouman
wrote:

jbeattie writes:

On Wednesday, October 25, 2017 at 8:59:47 AM UTC-7, wrote:
On Tuesday, October 24, 2017 at 5:22:03 PM UTC-7, John B. wrote:
On Tue, 24 Oct 2017 11:47:12 -0700, Joerg
wrote:


[ ... ]


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.

This is something I just can't understand. Indeed there is a
millisecond or two delay for the brake shoe to excise the water
directly in front of the initial application of the brake but after
the brake shoe touches the rim it pushes any water in the way off
without floating the shoe above it.

I see no reason whatsoever for disk brakes and their complications
even on most MTB's since a good V-Brake is longer lasting, just as
effective, cheaper and doesn't require special wheels and frame and
fork changes.

If you ride a lot in the rain and use a rim brake, you might go
through a front rim every 1-2 years -- at least based on the
experience of one of my commuter cohorts who just switched to discs.

And the slowly dying rims generate some really messy black sludge, at
least in my experience. I'm not sure why the "wax your chain to stay
clean" cohort hasn't noticed.

It is probably heresy to mention it, but some people wash their bikes,
particularly after riding in the rain. Amazing how easily all that
black sludge washes off with soap and water :-)


Oh yeah, now we have to wash out bikes after each rain ride. Standing
out there in the rain with sponge and shampoo. Great.

Of course not. You can ride a filthy nasty bicycle all covered over
with mud, blood and crud. In retrospect, perhaps an anti theft scheme.
After all, who would stoop to stealing such an ugly filthy thing?
--
Cheers,

John B.

On Fri, 27 Oct 2017 09:26:57 -0700, Joerg
wrote:

On 2017-10-27 07:11, jbeattie wrote:
On Friday, October 27, 2017 at 6:59:47 AM UTC-7, Joerg wrote:
On 2017-10-26 17:16, John B. wrote:
On Thu, 26 Oct 2017 17:08:10 -0400, Radey Shouman
wrote:

[...]

And the slowly dying rims generate some really messy black
sludge, at least in my experience. I'm not sure why the "wax
your chain to stay clean" cohort hasn't noticed.

It is probably heresy to mention it, but some people wash their
bikes, particularly after riding in the rain. Amazing how easily
all that black sludge washes off with soap and water :-)


Oh yeah, now we have to wash out bikes after each rain ride.
Standing out there in the rain with sponge and shampoo. Great.

The process can be pretty quick. Stand or lay the bike on the lawn
and hose it off carefully. You don't even have to put it on a
washstand. Do I do this? Rarely, but I was riding with my neighbor
who does, and it takes him about three minutes. I even did it last
weekend as kind of a bonding experience. He handed me the hose, so I
gave the bike a rinse. The bike was also pretty clean before we left
on our rain ride. If it were my commuter, a rinse would have just
re-arranged the mud.


Same here, my road bike is never particularly clean because of unpaved
road sections. Rinsing would just smear the dirt around.

I can't understand the fuss of many riders about their bikes. Almost
before every ride they have to pump up, Saturdays they spend cleaning
their various machines. I just like to ... ride. Thanks to thick tubes I
don't have to pump before a ride, I can just stash my water bottles and
food, replenish the bike wallet for a brewsky on the way home and go.
When I get home I park my bike in the garage, take the empty bottles and
walk into the house. Why should a bicycle require more pre- and
post-ride effort than a car?


OT, I was riding my son's 29er up Emigration Canyon a while back and
encountered a mud flow and sprayed crap all up the back of the seat
tube. We didn't bother rinsing that off, and when I came to visit
the next time, it was still there, hardened like cement. It was some
sort of clay or adobe. Some mud is super-tough and should be rinsed
off immediately.


Dirt on an MTB is a badge of honor. So far I've never cleaned my MTB
because it'll be dirty again 10 miles later.

http://www.analogconsultants.com/ng/bike/Muddy3.JPG

After a free bike wash due to rain:

http://www.analogconsultants.com/ng/bike/Muddy3.JPG

The remainder is caked in so hard that the soft side of a green-yellow
kitchen sponge won't get it off. The scrub pad of it might but then the
paint job is going to be scuffed and it'll collect dirt like a magnet.

Urban dwellers can buy spray-on dirt so their ride looks more manly. No
kidding.

https://www.theguardian.com/science/2005/jun/14/uknews

A rather revealing post. Do you bathe? Once a year on New Year's,
perhaps?
--
Cheers,

John B.

On Fri, 27 Oct 2017 16:11:31 -0700 (PDT), Sir Ridesalot
wrote:

On Friday, October 27, 2017 at 9:59:47 AM UTC-4, Joerg wrote:
Snipped
Oh yeah, now we have to wash out bikes after each rain ride. Standing
out there in the rain with sponge and shampoo. Great.

--
Regards, Joerg

http://www.analogconsultants.com/

Interesting that you do NOT want to do even basic maintenance/care of your bicycle. You much prefer to leave things go until something breaks ordoesn't work right; becaue it gives you something to complain about on Usenet.

Sheesh!

Cheers

He probably doesn't bathe, shave or brush his teeth either..... think
of all the time and effort he saves.
--
Cheers,

John B.

On Fri, 27 Oct 2017 08:06:33 -0700 (PDT), wrote:

On Friday, October 27, 2017 at 1:24:49 AM UTC-7, John B. wrote:
On Thu, 26 Oct 2017 13:37:00 -0400, Radey Shouman
wrote:

Joerg writes:

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

[ ... ]

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.

I don't understand the difference myself. When it's really raining,
meaning there's a continuous film of water on the road and a rooster
tail shooting forward off the front tire, I ride like a little old lady,
because of the delay in braking. Especially when it's dark, and leaves
and other blown down crap cover the road.

I suspect that may be the secret. I've never been "doored", perhaps
because if I have to ride past a line of parked cars where a door
might be opened I either slow down or ride further enough away that a
door wouldn't hit me.

Here the bike lane can be so narrow that the car door on a two-door totally covers the lane and there's no place to dodge because passing cars will spot that and not let you out.

If the choice is to run into a car door or be run over by a car then I
think I'd get off and walk. After all, running into a door, in the
litigatious society that you live in would likely result in a court
case that would beggar anyone living on a $500 a month retirement.

If spilling a cup of coffee in your lap is worth $2.8 million what is
the terror and delayed stress of some fiend on a bicycle coming out of
nowhere and smashing into your door just as you are trying to get
out.... Look, Look, there is the scar, right there on my arm and I
haven't had a good night's sleep since! The "partner" might even file
a co-suite for loss of connubial rights for the period he/she/it was
under treatment.
--
Cheers,

John B.

On Fri, 27 Oct 2017 09:32:04 -0700, Joerg
wrote:

On 2017-10-27 09:25, Frank Krygowski wrote:
On 10/27/2017 9:58 AM, Joerg wrote:

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?

sigh There are advantages and disadvantages to this equipment choice,
just as with other equipment choices. The disadvantages of discs have
been discussed. If they don't matter or apply to you, fine; but they
matter to others.


Many others just don't know any better. I have witnessed several people
riding a bike with hydraulic disc brakes for the first time and the
reaction was usually "WHOA!". Same with me, it almost sent me over the bar.


But I'll note that you're currently in a project to increase your disc's
diameter from something like 160mm or 180mm up to 200mm or more. You
seem to feel bigger diameter is better.


Because bigger is better here.


Well, even "better," why not go up to roughly 622mm? That's what lots
of us prefer, with cable actuation.


The disadvantages have been discussed ad nauseam. A rim brake is not a
disc brake. Not even close.

Care to explain the mechanical difference? I mean a rotating surface
and two friction pads that are tightened against it....
--
Cheers,

John B.