MTB disc brake caused wild fire

On 4/1/2018 1:18 AM, John B. wrote:
On Sat, 31 Mar 2018 21:41:14 -0400, Frank Krygowski
wrote:

On 3/31/2018 7:09 PM, John B. wrote:
On Sat, 31 Mar 2018 07:28:07 -0700, Joerg
wrote:

On 2018-03-30 16:56, John B. wrote:
On Fri, 30 Mar 2018 07:19:42 -0700, Joerg
wrote:

On 2018-03-30 02:04, John B. wrote:
On Thu, 29 Mar 2018 16:44:58 -0700, Joerg
wrote:

On 2018-03-29 14:34, Roger Merriman wrote:
sms wrote:
On 3/27/2018 7:39 AM, Joerg wrote:

Hydraulics also can suffer from sudden fade and that's scary. Then they
require bleeding which, depending on the kind, is a messy business. On
mine particularly so because there is no bleed kit for them. Cable disc
brakes are fine for pavement riding, just not for heavy duty MTB riding.

Avoid hydraulic disc brakes at all costs. Stick to mechanical disc brakes.



Which require constant adjustments as the pads wear, have cables that
weather eats, etc.

All my bikes have disks the CX/gravel/adventure road? Is cable the others
are hydraulic.

The cable is a lot more fuss, the Hydros just work, once set up you feed
them pads which is very easy.

Personally as someone who rides off-road plus high (ish) miles commuting
disks and preferably Hydro are game changers in terms of performance and
maintenance.

In terms of stuff like power, there is quite a overlap between the two, my
gravel bikes cable disks is about as powerful as the old commute MTB with
its older and cheaper Hydro brakes, both are embarrassing weak compared to
my Full suspension MTB.


I recently upgrade to 8" rotors front and back. That was the real game
changer. I can lock up either wheel with one finger and brake response
is prontissimo. Now I no longer have to worry when riding a steep trail
with some cargo in the back.

But I can lock up either, or both, wheels with vee brakes. With one
finger unless I want to lock both wheels which takes two fingers :-)

And, I might add, no requirement for bleeding either.


Now try that again when the rims are wet. With locking up I mean
instantly, tens of milliseconds.

A recent study demonstrated that an auditory stimulus takes 8 - 10 ms
to reach the brain, but on the other hand, a visual stimulus takes
20-40 ms. After the brain recognizes the event it must trigger the
muscles to react. Most texts seem to suggest that a good reaction time
is anywhere between 0.25 seconds and 0.35 seconds. Or 250 - 350
milliseconds. Your 10 millisecond reaction is much quicker then has
been tested in humans.... One can only assume that you are from
Krypton.


Ever heard of the term "muscle memory"?

Yup. and I am also aware of the old barroom game where you hold your
thumb and forefinger about an inch apart and a guy dangles a dollar
bill between them. the game is when he drops the bill you catch it
without moving your hand up or down, and you probably can't do it.

I've been playing the game for, probably, forty years and haven't come
across more then 10 or a dozen individuals in all those years who can
catch the bill.

As I said, one can only assume that you are from Krypton.

The dollar bill takes about 0.18 seconds to drop past one's fingers.

Try it with a $20. It seems to fall faster :-)


A $20 is worth a lot less now than a $10 was when first I
tried that.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On Sunday, April 1, 2018 at 7:15:31 AM UTC-7, Joerg wrote:
On 2018-03-31 23:44, wrote:
On Saturday, March 31, 2018 at 8:55:00 PM UTC+2, Joerg wrote:
On 2018-03-31 08:23, wrote:
Op zaterdag 31 maart 2018 16:20:28 UTC+2 schreef Joerg:
On 2018-03-30 10:31, wrote:
On Friday, March 30, 2018 at 5:03:12 PM UTC+2, Joerg wrote:
On 2018-03-30 07:08, jbeattie wrote:
On Thursday, March 29, 2018 at 11:09:37 PM UTC-7,
wrote:
On Friday, March 30, 2018 at 1:41:51 AM UTC+2, Joerg
wrote:
On 2018-03-29 14:32, AMuzi wrote:
On 3/29/2018 4:19 PM, wrote:
On Thursday, March 29, 2018 at 9:47:20 PM UTC+2,
Joerg wrote:
On 2018-03-29 12:25,
wrote:
On Thursday, March 29, 2018 at 4:09:07 PM
UTC+2, Joerg wrote:
On 2018-03-28 20:28, James wrote:
On 28/03/18 01:39, Joerg wrote:


Hydraulics also can suffer from sudden
fade and that's scary. Then they
require bleeding which, depending on
the kind, is a messy business. On mine
particularly so because there is no
bleed kit for them. Cable disc brakes
are fine for pavement riding, just not
for heavy duty MTB riding.


With the use of a few hose clamps, a file
that is harder than tool steel, nails and
rocks, I'm sure you could build a front
wheel for your MTB using a motorcycle
front hub, disc brake and lever.


After upgrading to 8" rotors front and back
I am quite pleased with the brake
performance of my MTB. The bleeding is
messy but only needs to be done about once
a year and takes 1/2h.



Once a year? Why?


Because after about a year the lever for the
rear brake starts feeling soft. Braking is
still fine and most other riders just leave it
like that but I like the pressure point nice
and hard. Also, the slightest amount of air in
the line near the caliper can cause a brake
failure on a long downhill which here in the
hills is not cool.


Never bleed my brakes on my cross bike for 4
years now and they feel like they did on day 1.
Shimano must be doing something right.

Says the guy riding in Nederlands where there are
no mountain lions. Of course they work for you.


There are also no hills and dirt and stuff, or having
to ride through rivers. My MTB brake calipers
regularly reach a state where you can't even seem
them anymore.

The guys using Shimano out here need to bleed them as
well, except they can't use the DOT4 fluid from the
garage cabinet.

-- Regards, Joerg

http://www.analogconsultants.com/

As I said they are on my crossbike which see more mud
and dirt you can image. And lots of steep short up and
downhills. In total I spent 3 months in California
during my trips. Never had a day of rain, some
drizzle/fog in San Francisco...


Where do you take your CX bike? Eastern Belgium? Or to the
Alps?


Just in my backyard, most of the time just across the German
border. Once in a while I make a clip of our ride. You can
download (it is save) a clip of a typical sunday morning
winter ride here

https://we.tl/6awaXeHLBp


That's not a lot of dirt, just wee mud puddles on a meandering
forest path. Also, it's totally flat so you won't experience
what I did when I rode an MTB with rim brakes: Muddy trail like
yours but downhill. Reached in, nothing, only horrid sandpaper
sounds, sharp turn with cliff approaching fast. I almost needed
a bathroom after that. This simply does not happen with disc
brakes.

-- Regards, Joerg

http://www.analogconsultants.com/

Not unusual:

https://photos.app.goo.gl/0KviHxMzDlHsok3H3


Right, and an attentive viewer will notice that the bike in your
photo link has disc brakes. Applying rim brakes under that
condition will cause a substantial delay until the brake force
appears. In your video it wouldn't matter because it's all
flatlands and you won't encounter a sharp turn with a cliff on the
outside. Like this are 0:51min, 1:13min, 1:29min, 1:35min and so
on:

https://www.youtube.com/watch?v=1USLVraV4mU

It's one of my regular routes. I would not want to ride that in the
rain with a rim brake bike, it would be no fun.

Mud will also eat rims. At least out here where there is lots of
sand mixed in such mud. When my old MTB had around 1000mi on it
there were already deep grooves in the rims. By that time I had
made the decision that this isn't going to work and bought a proper
MTB with disc brakes and all. I still have the old one but it is
now my "commute mule" to take along in the SUV on business trips.
Most of those are to the flatlands and there the bike is fine.

-- Regards, Joerg

http://www.analogconsultants.com/

I think no one is arguing that in that kind of situation hydraulic
disk brakes are the better choice. That doesn't mean that you die if
you use rimbrakes.


You could get in trouble, for example, if an unforseen situation comes
up. Like that logging truck driver not seeing you. In my case it was a
buck that didn't pay attention and cut diagonally across the singletrack
without looking at me. With rim brakes we'd have collided. Couldn't
believe it. He just kept running and running, without looking back even
once.

And yet, for decades, I rode rim brakes in the rain, mud, etc. The downside was the rim-lathe of grit against aluminum rims and momentary loss of braking, but on a wet surface, the real problem has always been traction.

The two times my bike didn't stop in the rain due to brake issues we (1) pulling a trailer with my son in it on poorly adjusted cantis with STI levers, and (2) descending a sled run out of the West Hills with worn and unadjusted pads on cable discs. I stopped and dialed in the pads which solved that problem. In both cases, hard braking would have had me skidding down a wet road or path.

I rode maybe 40-50 miles yesterday all climbing and descending on my uber-bike (no instrumentation and no idea of elevation) with direct mount calipers. It was dry, and I didn't give my brakes a moment's thought. My braking issues were all about when I slowed and road surface quality.

-- Jay Beattie.

On 4/1/2018 9:23 AM, jbeattie wrote:

snip

And yet, for decades, I rode rim brakes in the rain, mud, etc. The downside was the rim-lathe of grit against aluminum rims and momentary loss of braking, but on a wet surface, the real problem has always been traction.

The two times my bike didn't stop in the rain due to brake issues we (1) pulling a trailer with my son in it on poorly adjusted cantis with STI levers, and (2) descending a sled run out of the West Hills with worn and unadjusted pads on cable discs. I stopped and dialed in the pads which solved that problem. In both cases, hard braking would have had me skidding down a wet road or path.

I rode maybe 40-50 miles yesterday all climbing and descending on my uber-bike (no instrumentation and no idea of elevation) with direct mount calipers. It was dry, and I didn't give my brakes a moment's thought. My braking issues were all about when I slowed and road surface quality.

You may have done this for decades, but you were not having any fun
doing so.

I have a friend who used to go on and on about the greatness of Price
Club (now Costco). I asked him "Tom, how did you survive before Price
Club?" His response: "I survived, but it wasn't much of a life."

Frank Krygowski wrote:
On 3/29/2018 5:34 PM, Roger Merriman wrote:
sms wrote:
On 3/27/2018 7:39 AM, Joerg wrote:

Hydraulics also can suffer from sudden fade and that's scary. Then they
require bleeding which, depending on the kind, is a messy business. On
mine particularly so because there is no bleed kit for them. Cable disc
brakes are fine for pavement riding, just not for heavy duty MTB riding.

Avoid hydraulic disc brakes at all costs. Stick to mechanical disc brakes.



Which require constant adjustments as the pads wear, have cables that
weather eats, etc.

All my bikes have disks the CX/gravel/adventure road? Is cable the others
are hydraulic.

The cable is a lot more fuss, the Hydros just work, once set up you feed
them pads which is very easy.

Personally as someone who rides off-road plus high (ish) miles commuting
disks and preferably Hydro are game changers in terms of performance and
maintenance.

In terms of stuff like power, there is quite a overlap between the two, my
gravel bikes cable disks is about as powerful as the old commute MTB with
its older and cheaper Hydro brakes, both are embarrassing weak compared to
my Full suspension MTB.

"Embarrassingly weak" sounds strange to me. Aren't you really talking
about overall mechanical advantage - that is, lever force vs. braking force?

Practical braking force, especially off-road, is limited by traction
and/or by risk of pitchover. I fail to see why getting that amount of
force from a one pound lever force is better than getting it from a two
pound lever force. I can squeeze a two pound force all day.

Modern MTB’s have much slack geometry, and frankly it’s a fairly green
Cyclist who can’t adjust some of there weight, why do you think dropper
posts are in use?

Again Modern MTB tyres can exert a surprising amount of grip even technical
terrain.

Has to be said it might be possible for a rim brake in the dry to exert the
same force, but once off perfect conditions its performance declines, I
have fond memories of glowing forearms from long wet MTB descents.

Such descents even on rigid bikes with disks such as my Gravel bike, are
far easier and frankly more fun!

Roger Merriman

Joerg wrote:
On 2018-03-29 18:28, jbeattie wrote:
On Thursday, March 29, 2018 at 5:25:55 PM UTC-7, Frank Krygowski
wrote:
On 3/29/2018 5:34 PM, Roger Merriman wrote:
sms wrote:
On 3/27/2018 7:39 AM, Joerg wrote:

Hydraulics also can suffer from sudden fade and that's scary.
Then they require bleeding which, depending on the kind, is a
messy business. On mine particularly so because there is no
bleed kit for them. Cable disc brakes are fine for pavement
riding, just not for heavy duty MTB riding.

Avoid hydraulic disc brakes at all costs. Stick to mechanical
disc brakes.



Which require constant adjustments as the pads wear, have cables
that weather eats, etc.

All my bikes have disks the CX/gravel/adventure road? Is cable
the others are hydraulic.

The cable is a lot more fuss, the Hydros just work, once set up
you feed them pads which is very easy.

Personally as someone who rides off-road plus high (ish) miles
commuting disks and preferably Hydro are game changers in terms
of performance and maintenance.

In terms of stuff like power, there is quite a overlap between
the two, my gravel bikes cable disks is about as powerful as the
old commute MTB with its older and cheaper Hydro brakes, both are
embarrassing weak compared to my Full suspension MTB.

"Embarrassingly weak" sounds strange to me. Aren't you really
talking about overall mechanical advantage - that is, lever force
vs. braking force?

Practical braking force, especially off-road, is limited by
traction and/or by risk of pitchover. I fail to see why getting
that amount of force from a one pound lever force is better than
getting it from a two pound lever force. I can squeeze a two pound
force all day.

Gads, I'm afraid to ride home on my cable discs, and I might even
ride home on this odd-ball trail:
https://swtrails.files.wordpress.com...er-freeway.jpg


In California might not want to. There'd be a sizeable homeless camp
under there and they might not like it when someone rolls through
"their" turf.


Right under I-5. And adding to the danger, I'll be on rim brakes this
weekend. Eeeeeek!

MTBs are a different deal, and I can see being wedded to hydraulic
discs. And I really do like the hydraulic discs on my road bikes.
Nothing like the smell of mineral oil in the morning. Do I need
hydraulic discs? No. I've ridden all the passes in Joergville,
loaded and unloaded with caliper brakes and cantis -- Monitor,
Ebbetts, Pacific Grade, Luther, Carson, Sonora, Tioga -- almost all
of HWY 49. The Rockies, Cascades -- all them moun-tains across the
US. No runaway train stories. I guess I just lack gnarliness.


On a road bike under regular conditions rim brakes are ok. Not great but
ok. They do become a problem when it's pouring and then, for example, a
guy in a logging truck didn't see you and suddenly accelerates on into
the road. Last time that happened to me it was "only" a pickup truck but
crashing into its side isn't fun either. I was able to stop but barely,
was getting ready to bail.


There is a fair variation in rim brakes, my Previous CX/gravel etc bike
hand canti and where very weak brakes, but dual pivots are fine, never felt
worrying poor, performance did drop off in wet grimy conditions.

Disks are better but they are much better off road, on road even mucky wet
back roads it’s not that much difference.

Roger Merriman

On Sun, 01 Apr 2018 07:29:17 -0700, Joerg
wrote:

On 2018-03-31 23:18, John B. wrote:
On Sat, 31 Mar 2018 21:41:14 -0400, Frank Krygowski
wrote:

On 3/31/2018 7:09 PM, John B. wrote:
On Sat, 31 Mar 2018 07:28:07 -0700, Joerg
wrote:

[...]



Ever heard of the term "muscle memory"?

Yup. and I am also aware of the old barroom game where you hold your
thumb and forefinger about an inch apart and a guy dangles a dollar
bill between them. the game is when he drops the bill you catch it
without moving your hand up or down, and you probably can't do it.

I've been playing the game for, probably, forty years and haven't come
across more then 10 or a dozen individuals in all those years who can
catch the bill.


Out here in the Wild West it used to be that if the muscle memory in
your index finger wasn't fast enough your life time was generally
shorter. Unless you avoided gun fights.

https://www.youtube.com/watch?v=v5WjkI5FuP0


And yet, in the history of the "Old West" there was only one "quick
draw" type of gunfight.

And, given that most pistols of that period were "single action" it
was a quick thumb that counted :-)





As I said, one can only assume that you are from Krypton.


Sometimes others seem to think that as well. This year I brought my tax
stuff to the CPA via road bike which they said is highly unusual. A few
years ago I came via singletrack on the MTB, shook off some mud and made
sure the bottoms of my shoes were clean enough not to dirty their lobby
carpet. The receptionist asked with wide eyes "You came from WHERE?"


The dollar bill takes about 0.18 seconds to drop past one's fingers.

Try it with a $20. It seems to fall faster :-)


Not anymore, inflation ate some of that. Try it with a 20 Baht bill,
then you should be able to catch it :-)
--
Cheers,

John B.

On 2018-04-01 13:53, Roger Merriman wrote:
Frank Krygowski wrote:
On 3/29/2018 5:34 PM, Roger Merriman wrote:
sms wrote:
On 3/27/2018 7:39 AM, Joerg wrote:

Hydraulics also can suffer from sudden fade and that's scary. Then they
require bleeding which, depending on the kind, is a messy business. On
mine particularly so because there is no bleed kit for them. Cable disc
brakes are fine for pavement riding, just not for heavy duty MTB riding.

Avoid hydraulic disc brakes at all costs. Stick to mechanical disc brakes.



Which require constant adjustments as the pads wear, have cables that
weather eats, etc.

All my bikes have disks the CX/gravel/adventure road? Is cable the others
are hydraulic.

The cable is a lot more fuss, the Hydros just work, once set up you feed
them pads which is very easy.

Personally as someone who rides off-road plus high (ish) miles commuting
disks and preferably Hydro are game changers in terms of performance and
maintenance.

In terms of stuff like power, there is quite a overlap between the two, my
gravel bikes cable disks is about as powerful as the old commute MTB with
its older and cheaper Hydro brakes, both are embarrassing weak compared to
my Full suspension MTB.

"Embarrassingly weak" sounds strange to me. Aren't you really talking
about overall mechanical advantage - that is, lever force vs. braking force?

Practical braking force, especially off-road, is limited by traction
and/or by risk of pitchover. I fail to see why getting that amount of
force from a one pound lever force is better than getting it from a two
pound lever force. I can squeeze a two pound force all day.

Modern MTB’s have much slack geometry, and frankly it’s a fairly green
Cyclist who can’t adjust some of there weight, why do you think dropper
posts are in use?


You wouldn't believe it but someone (Frank?) posted a video here a while
ago about a series crash in a steep downhill curve during a Tour de
France. The majority of riders who crashed did not scoot behind the
saddle for max braking action. These were all professional riders yet
they clearly lacked instincts any serious MTB rider has.


Again Modern MTB tyres can exert a surprising amount of grip even technical
terrain.

Has to be said it might be possible for a rim brake in the dry to exert the
same force, but once off perfect conditions its performance declines, I
have fond memories of glowing forearms from long wet MTB descents.

Such descents even on rigid bikes with disks such as my Gravel bike, are
far easier and frankly more fun!


Also much cheaper because after 2000mi of rough riding with rim brakes
the rims might be through and that gets expensive. Even replacing pads
is quicker with disc brakes. Drop out the wheel, remove the spring, old
pads drop out, scoot in new pads and spring, wheel back in, done. No
adjusting, toe-in and all that.

The prices are also interestingly different. Not that this matter much
but just noting. The lowest cost but well working pads for rim brakes I
found are Clarks from the UK, around $4-5/pair. The lowest cost pads
with good quality for Promax Decipher hydraulic disc brakes are $2/pair
from Hangzhou Novich.

--
Regards, Joerg

http://www.analogconsultants.com/

On Monday, April 2, 2018 at 4:36:21 PM UTC+2, Joerg wrote:
On 2018-04-01 13:53, Roger Merriman wrote:
Frank Krygowski wrote:
On 3/29/2018 5:34 PM, Roger Merriman wrote:
sms wrote:
On 3/27/2018 7:39 AM, Joerg wrote:

Hydraulics also can suffer from sudden fade and that's scary. Then they
require bleeding which, depending on the kind, is a messy business. On
mine particularly so because there is no bleed kit for them. Cable disc
brakes are fine for pavement riding, just not for heavy duty MTB riding.

Avoid hydraulic disc brakes at all costs. Stick to mechanical disc brakes.



Which require constant adjustments as the pads wear, have cables that
weather eats, etc.

All my bikes have disks the CX/gravel/adventure road? Is cable the others
are hydraulic.

The cable is a lot more fuss, the Hydros just work, once set up you feed
them pads which is very easy.

Personally as someone who rides off-road plus high (ish) miles commuting
disks and preferably Hydro are game changers in terms of performance and
maintenance.

In terms of stuff like power, there is quite a overlap between the two, my
gravel bikes cable disks is about as powerful as the old commute MTB with
its older and cheaper Hydro brakes, both are embarrassing weak compared to
my Full suspension MTB.

"Embarrassingly weak" sounds strange to me. Aren't you really talking
about overall mechanical advantage - that is, lever force vs. braking force?

Practical braking force, especially off-road, is limited by traction
and/or by risk of pitchover. I fail to see why getting that amount of
force from a one pound lever force is better than getting it from a two
pound lever force. I can squeeze a two pound force all day.

Modern MTB’s have much slack geometry, and frankly it’s a fairly green
Cyclist who can’t adjust some of there weight, why do you think dropper
posts are in use?


You wouldn't believe it but someone (Frank?) posted a video here a while
ago about a series crash in a steep downhill curve during a Tour de
France. The majority of riders who crashed did not scoot behind the
saddle for max braking action. These were all professional riders yet
they clearly lacked instincts any serious MTB rider has.

Joerg telling pro road riders how to brake. That will be the day.


Again Modern MTB tyres can exert a surprising amount of grip even technical
terrain.

Has to be said it might be possible for a rim brake in the dry to exert the
same force, but once off perfect conditions its performance declines, I
have fond memories of glowing forearms from long wet MTB descents.

Such descents even on rigid bikes with disks such as my Gravel bike, are
far easier and frankly more fun!


Also much cheaper because after 2000mi of rough riding with rim brakes
the rims might be through and that gets expensive. Even replacing pads
is quicker with disc brakes. Drop out the wheel, remove the spring, old
pads drop out, scoot in new pads and spring, wheel back in, done. No
adjusting, toe-in and all that.

The prices are also interestingly different. Not that this matter much
but just noting. The lowest cost but well working pads for rim brakes I
found are Clarks from the UK, around $4-5/pair. The lowest cost pads
with good quality for Promax Decipher hydraulic disc brakes are $2/pair
from Hangzhou Novich.

It is amazing that you still use ancient (Shimano 600) rim brakes on your road bike.


Lou

On 2018-04-02 08:57, wrote:
On Monday, April 2, 2018 at 4:36:21 PM UTC+2, Joerg wrote:
On 2018-04-01 13:53, Roger Merriman wrote:
Frank Krygowski wrote:
On 3/29/2018 5:34 PM, Roger Merriman wrote:
sms wrote:
On 3/27/2018 7:39 AM, Joerg wrote:

Hydraulics also can suffer from sudden fade and that's scary. Then they
require bleeding which, depending on the kind, is a messy business. On
mine particularly so because there is no bleed kit for them. Cable disc
brakes are fine for pavement riding, just not for heavy duty MTB riding.

Avoid hydraulic disc brakes at all costs. Stick to mechanical disc brakes.



Which require constant adjustments as the pads wear, have cables that
weather eats, etc.

All my bikes have disks the CX/gravel/adventure road? Is cable the others
are hydraulic.

The cable is a lot more fuss, the Hydros just work, once set up you feed
them pads which is very easy.

Personally as someone who rides off-road plus high (ish) miles commuting
disks and preferably Hydro are game changers in terms of performance and
maintenance.

In terms of stuff like power, there is quite a overlap between the two, my
gravel bikes cable disks is about as powerful as the old commute MTB with
its older and cheaper Hydro brakes, both are embarrassing weak compared to
my Full suspension MTB.

"Embarrassingly weak" sounds strange to me. Aren't you really talking
about overall mechanical advantage - that is, lever force vs. braking force?

Practical braking force, especially off-road, is limited by traction
and/or by risk of pitchover. I fail to see why getting that amount of
force from a one pound lever force is better than getting it from a two
pound lever force. I can squeeze a two pound force all day.

Modern MTB’s have much slack geometry, and frankly it’s a fairly green
Cyclist who can’t adjust some of there weight, why do you think dropper
posts are in use?


You wouldn't believe it but someone (Frank?) posted a video here a while
ago about a series crash in a steep downhill curve during a Tour de
France. The majority of riders who crashed did not scoot behind the
saddle for max braking action. These were all professional riders yet
they clearly lacked instincts any serious MTB rider has.

Joerg telling pro road riders how to brake. That will be the day.


Yes, I do know better braking techniques than many of those riders did
and would have likely either not crashed or not as hard. I found the
video again, it wasn't the Tour de France but a race in Utah:

https://www.youtube.com/watch?v=hRM3bFXlyNk

If you do not know what the first rider who crashed and some others did
wrong I suggest you refrain from MTB riding in the mountains.



Again Modern MTB tyres can exert a surprising amount of grip even technical
terrain.

Has to be said it might be possible for a rim brake in the dry to exert the
same force, but once off perfect conditions its performance declines, I
have fond memories of glowing forearms from long wet MTB descents.

Such descents even on rigid bikes with disks such as my Gravel bike, are
far easier and frankly more fun!


Also much cheaper because after 2000mi of rough riding with rim brakes
the rims might be through and that gets expensive. Even replacing pads
is quicker with disc brakes. Drop out the wheel, remove the spring, old
pads drop out, scoot in new pads and spring, wheel back in, done. No
adjusting, toe-in and all that.

The prices are also interestingly different. Not that this matter much
but just noting. The lowest cost but well working pads for rim brakes I
found are Clarks from the UK, around $4-5/pair. The lowest cost pads
with good quality for Promax Decipher hydraulic disc brakes are $2/pair
from Hangzhou Novich.

It is amazing that you still use ancient (Shimano 600) rim brakes on your road bike.


Why?

--
Regards, Joerg

http://www.analogconsultants.com/

On 4/2/2018 10:36 AM, Joerg wrote:
On 2018-04-01 13:53, Roger Merriman wrote:
Frank Krygowski wrote:


Practical braking force, especially off-road, is limited by traction
and/or by risk of pitchover. I fail to see why getting that amount of
force from a one pound lever force is better than getting it from a two
pound lever force. I can squeeze a two pound force all day.

Modern MTB’s have much slack geometry, and frankly it’s a fairly green
Cyclist who can’t adjust some of there weight, why do you think dropper
posts are in use?


You wouldn't believe it but someone (Frank?) posted a video here a while
ago about a series crash in a steep downhill curve during a Tour de
France. The majority of riders who crashed did not scoot behind the
saddle for max braking action. These were all professional riders yet
they clearly lacked instincts any serious MTB rider has.

It wasn't posted by me, but it was the Tour of Utah, not the Tour de
France. And some riders slid back on their seats, some did not.
https://www.youtube.com/watch?v=tyRqN7ukxrw

Joerg, you seem to think sliding back on the seat is magic. It's not.
Under ideal conditions, it might allow a bit greater bike control by
raising the maximum deceleration before losing rear wheel contact. I
calculate 7.6% increase in rear "liftoff" deceleration with my touring
bike. In the video, I doubt that modest difference would have prevented
any crashes. And in many sudden emergency situations, it's probably
better to think about other things than "Where's my butt?"

Back to gripping the lever: Drop post or no, sliding back or no, I don't
see much benefit in reducing lever force below a certain level. Whether
we're talking about brake mechanical advantage, or headlight brightness,
or clothing visibility or whatever, there's no need to go to ridiculous
extremes.


--
- Frank Krygowski