Ventoso blasts the use of disc brakes in the peloton

On Thu, 28 Apr 2016 06:47:57 -0700, Joerg
wrote:

On 2016-04-27 19:48, James wrote:
On 28/04/16 06:42, Joerg wrote:
On 2016-04-25 12:38, Frank Krygowski wrote:
On Monday, April 25, 2016 at 10:16:42 AM UTC-4, Joerg wrote:

You and I then have to remain in disagreement about that. Yes, I have
ridden bicycles with mechanical disc brakes. No, I did not like the
braking performance on those. Yes, I have personally experienced the
snapping of a front brake cable and the subsequent crash into the rear
of a car. There are reasons why motor vehicles are now almost
exclusively equipped with hydraulic brake system.

The real reason cars moved to hydraulic brakes is completely
irrelevant to
cyclists. Before hydraulics, cars used various mechanical linkages to
activate brakes. The problem was the great difficulty of keeping the
left
and right side braking forces suitably equal. It was far to easy to
have
a brake microscopically misadjusted, and have it pull violently left or
right under hard braking. Hydraulics cured that, since the pressure
in the
system is the same on the left or right sides.


Wire operated brakes can be auto-calibrated just as easily, that was not
the reason. Also, hydraulics were indroduced well before discs became
popular. I remember that I had to adjust the front brakes on my Citroen
2CV at least twice a year or they'd pull hard in one direction. Drum
brakes, hydraulically operated. The reason for the veering was uneven
wear so you had to adjust the pivot point ever so slightly to make both
sides press evenly.


I owned a '67 Landrover Series IIA with hydraulic operated 4 wheel
drums. The *only* time it pulled hard was after one side got wet, or
both got wet and one dried before the other.

Adjustment had little to do with pulling one way or the other, and most
about how many pumps of the brake pedal it took before you had any
brakes at all.


It has to do with the pivot point. On many drum brakes you can (and have
to) adjust two things:

a. Clearance to the drum

b. Pivot point

Some cars did not have pivot adjust and then you get uneven wear in the
brake material, requiring you to change it out earlier. You could even
get an "amplifier effect" and adjust the pivots so the pad engages first
very close to the pivot. Made it feel as if that old Citroen had
power-assisted brakes (which it didn't). But that would wear off fast
and you could not do this too often. IIRC the rear drum brakes had no
pivot adjust but those hardly wore.

If the pivot adjusts where uneven the brake with the pivot adjusted
closer would work harder ("amplified") and the vehicle pulled to that side.

Are you sure about this "adjustable pivot point"? I ask as I date back
a few years and I have never seen such a thing. A brake with a moving
pivot, called a "self energizing" brake certainly but none where there
was a fixed pivot that could be, in some manner fixed in different
spots or slid along a groove in some way.
--

Cheers,

John B.

On Thu, 28 Apr 2016 09:21:16 -0700, Joerg
wrote:

On 2016-04-28 08:19, Frank Krygowski wrote:
On 4/28/2016 9:50 AM, Joerg wrote:
On 2016-04-27 16:13, Frank Krygowski wrote:
On 4/27/2016 4:42 PM, Joerg wrote:
On 2016-04-25 12:38, Frank Krygowski wrote:

The real reason cars moved to hydraulic brakes is completely
irrelevant to
cyclists. Before hydraulics, cars used various mechanical linkages to
activate brakes. The problem was the great difficulty of keeping the
left
and right side braking forces suitably equal. It was far to easy to
have
a brake microscopically misadjusted, and have it pull violently
left or
right under hard braking. Hydraulics cured that, since the pressure
in the
system is the same on the left or right sides.


Wire operated brakes can be auto-calibrated just as easily...

Oh? Left vs. right? How?


Picture a short rod. Actuating cable pulls in the center, lines to the
brake are connected to each side.

And if left & right cable friction or lever friction are slightly
different?


That means you've either damaged them or were sloppy on maintenance.

I am a checklist kind of guy when it comes to vehicles and other
important things. Among several things I test the function of the hand
brake before every ride in a car, wether mine, my wife's or any other.
Why do you think I never notice any veer when checking the
cable-actuated hand brake?

Hint: Both of our vehicles are around 20 years old and _never_ needed
any veer-related adjustment in those cables. I doubt that there even is
such an adjustment option anymore because the automotive industry has
solved that problem many decades ago.

"Both our vehicles are 20 years old"..... and they don't have
hydraulic brakes? Or you trying to equate the "emergency brake" system
with the normal brake system?

If so you might try disconnecting your hydraulic brake system and try
driving with the "emergency brake". You will realize very rapidly that
it really isn't am "emergency" brake but in reality a "parking" brake
intended only to hold the vehicle stationary after it has stopped.

Long story short, that is not why hydraulic brakes came about.
--

Cheers,

John B.

On Thu, 28 Apr 2016 10:00:33 -0700, Joerg
wrote:

On 2016-04-28 08:30, Frank Krygowski wrote:
On 4/28/2016 9:54 AM, Joerg wrote:
On 2016-04-27 16:16, Frank Krygowski wrote:
On 4/27/2016 4:58 PM, Joerg wrote:
On 2016-04-25 19:33, Frank Krygowski wrote:
On 4/25/2016 10:58 AM, Joerg wrote:
On 2016-04-25 05:38, John B. wrote:


I very much doubt if it would be possible to create a derailer
system
for use with o (or x)-ring chains. ...


Sure it can be done. But we have to venture out of our cave and into
modern technology. It doesn't all have to be reiinvented since the
motorcycle industry already has. One idea, simplified for clarity:

Only one bearing and the rear wheel mount on the left. Of course, the
frame needs to be different but here again we can simply learn from
the
motorcycle industry. Then a freehub that can slide the cassette
left to
right, controlled by an index shifter. The derailer is in a fixed
position and not controlled. If using two or more chain rings up
front
the derailer and cassette will both have to scoot syncronously with
the
front derailer which is easy to accomplish. Bingo, no more chain
skew.

:-) That makes even less sense than the "concept bikes" that are
regularly churned out (in digital-only form, of course!) by
students of
"industrial design."

http://idesignow.com/inspiration-2/3...e-designs.html


Read the above again. It's got nothing to do with fashion stuff like
that.

It's no more practical. Try building a prototype and you'll see.

Yeah, I know - you don't have time to actually [dis]prove any of your
amazing ideas. Your time is all taken up with telling Usenet that
you're the only person competent at evaluating bike designs.


sigh

https://ixquick-proxy.com/do/show_pi...38e9a9415f0421



There. That was easy. You still cannot imagine how a moving cassette
would work on this? Then I can't help you.

The issue isn't the single side axle support. (I've ridden a BMW
motorcycle for decades; of course I know about that. I once owned a
recumbent trike whose front axles were supported only on the inboard side.

But your sliding cassette idea makes it sound like you've never
personally built anything mechanical.


I have and I could also make this work.


Why not give us some detailed sketches about how you would do this? Cost
estimates would be a bonus.


Right, and then you would want a Youtube video :-)


Yeah, I know... you have no time for anything but posting complaints.
But an actual design would do a lot more for your reputation here than
your constant hand waving and complaining.


Your ME capabilities don't seem to be too great if you can't picture how
it can be done.

For those who can imagine mechanical things and don't need every idea as
a fully completed and ECO-released CAD drawing:

Picture a freehub body that is a little over 2x longer than the
cassette. The outside has a spring that always tries to push the
cassette to its left peg which would translate to the chain being on the
smallest sprocket. Unless the shifter tells it not to. The inside
contains a bearing that slides on the splines just like the cassette
does but the outer ring of that bearing does not touch the cassette.


In other words you are going to have a, lets say 9 speed cassette,
which is approximately 1-1/2 inches wide sliding back and forth to
align the various cogs with the straight chain. If so then you rear
"free hub", for want of a better word, is going to be approximately 3
inches wide and the entire wheel hub will be about 7 inches wide,
between the drop-outs.

Now then, if you are going to use a spoke wheel - much, much, lighter
then a cast aluminum motorcycle wheel - how is this to be arranged?

Will we center the wheel over the entire hub and wide "free hub"? If
so the free hub side spokes are going to be either straight or angled
toward the bicycle's left side....

Or maybe you intend to center the hub and have the extra 3 inches of
free hub extending in a great bulge on the R.H. side of the bike?

One has to ask, what is the cost of this concoction? How will this
sliding cassette be protected from dirt on its sliding surfaces? How
much is it going to weigh?

And then the BIG ONE, will people buy this conglomeration instead of
the present derailer system? After all, to most cyclists the cost of a
chain is, one might say, insignificant.

You problem is that you are very much the "amateur engineer" and don't
even begin to consider that one cannot design something in isolation.
One has to design a whole.

As an example, your constant problems with your weak bicycle parts.

Years ago I saw a bicycle that was almost surely unbreakable. It was
made of 1/2" and 3/4" re-bar and arc welded together. Apparently, from
the photos, it wasn't a "concept bike" but rather a bicycle that was
ridden as transportation.

It was certainly unbreakable but did have one, minor, shortcoming....
it weighed something like a hundred kilos.

But Hey, who cares about weight, it is unbreakable!

--

Cheers,

John B.

On Thursday, April 28, 2016 at 8:30:54 AM UTC-7, Frank Krygowski wrote:
snip
There. That was easy. You still cannot imagine how a moving cassette
would work on this? Then I can't help you.

The issue isn't the single side axle support. (I've ridden a BMW
motorcycle for decades; of course I know about that. I once owned a
recumbent trike whose front axles were supported only on the inboard side.

What is the purpose of that design? I never understood the Cannondale Lefty. A one-leg fork looks sketchy.

-- Jay Beattie.

Am 29.04.2016 um 06:11 schrieb jbeattie:
On Thursday, April 28, 2016 at 8:30:54 AM UTC-7, Frank Krygowski wrote:
snip

The issue isn't the single side axle support. I once owned a
recumbent trike whose front axles were supported only on the inboard
side.

What is the purpose of that design?

Why are cars designed with one-sided axle support? Whenever the wheels
are on the outside of a vehicle, one-sided axle support is a lot easier
to implement than two-sided axle support. So all trike I know have
one-sided axle support; typically you can take standard bicycle wheels
and 'only' increase the size of the axle by a few mm (I believe mine had
a Sachs drum brake wheel with different bearings so that a 10mm axle
could fit through it).

On Fri, 29 Apr 2016 11:17:20 +0200, Rolf Mantel
wrote:

Am 29.04.2016 um 06:11 schrieb jbeattie:
On Thursday, April 28, 2016 at 8:30:54 AM UTC-7, Frank Krygowski wrote:
snip

The issue isn't the single side axle support. I once owned a
recumbent trike whose front axles were supported only on the inboard
side.

What is the purpose of that design?

Why are cars designed with one-sided axle support? Whenever the wheels
are on the outside of a vehicle, one-sided axle support is a lot easier
to implement than two-sided axle support. So all trike I know have
one-sided axle support; typically you can take standard bicycle wheels
and 'only' increase the size of the axle by a few mm (I believe mine had
a Sachs drum brake wheel with different bearings so that a 10mm axle
could fit through it).

Cars designed? Think Ox cart, Conestoga, chariot :-)
--

Cheers,

John B.

On 2016-04-28 17:57, Frank Krygowski wrote:
On 4/28/2016 7:08 PM, Joerg wrote:
On 2016-04-28 15:35, Frank Krygowski wrote:
On 4/28/2016 1:00 PM, Joerg wrote:
On 2016-04-28 08:30, Frank Krygowski wrote:
On 4/28/2016 9:54 AM, Joerg wrote:
On 2016-04-27 16:16, Frank Krygowski wrote:
On 4/27/2016 4:58 PM, Joerg wrote:
On 2016-04-25 19:33, Frank Krygowski wrote:
On 4/25/2016 10:58 AM, Joerg wrote:
On 2016-04-25 05:38, John B. wrote:


I very much doubt if it would be possible to create a derailer
system
for use with o (or x)-ring chains. ...


Sure it can be done. But we have to venture out of our cave and
into
modern technology. It doesn't all have to be reiinvented since
the
motorcycle industry already has. One idea, simplified for
clarity:

Only one bearing and the rear wheel mount on the left. Of course,
the
frame needs to be different but here again we can simply learn
from
the
motorcycle industry. Then a freehub that can slide the cassette
left to
right, controlled by an index shifter. The derailer is in a fixed
position and not controlled. If using two or more chain rings up
front
the derailer and cassette will both have to scoot syncronously
with
the
front derailer which is easy to accomplish. Bingo, no more chain
skew.

:-) That makes even less sense than the "concept bikes" that are
regularly churned out (in digital-only form, of course!) by
students of
"industrial design."

http://idesignow.com/inspiration-2/3...e-designs.html


Read the above again. It's got nothing to do with fashion stuff
like
that.

It's no more practical. Try building a prototype and you'll see.

Yeah, I know - you don't have time to actually [dis]prove any of
your
amazing ideas. Your time is all taken up with telling Usenet that
you're the only person competent at evaluating bike designs.


sigh

https://ixquick-proxy.com/do/show_pi...38e9a9415f0421







There. That was easy. You still cannot imagine how a moving cassette
would work on this? Then I can't help you.

The issue isn't the single side axle support. (I've ridden a BMW
motorcycle for decades; of course I know about that. I once owned a
recumbent trike whose front axles were supported only on the inboard
side.

But your sliding cassette idea makes it sound like you've never
personally built anything mechanical.


I have and I could also make this work.


Why not give us some detailed sketches about how you would do this?
Cost
estimates would be a bonus.


Right, and then you would want a Youtube video :-)


Yeah, I know... you have no time for anything but posting complaints.
But an actual design would do a lot more for your reputation here than
your constant hand waving and complaining.


Your ME capabilities don't seem to be too great if you can't picture
how
it can be done.

For those who can imagine mechanical things and don't need every
idea as
a fully completed and ECO-released CAD drawing:

Picture a freehub body that is a little over 2x longer than the
cassette. The outside has a spring that always tries to push the
cassette to its left peg which would translate to the chain being on
the
smallest sprocket. Unless the shifter tells it not to. The inside
contains a bearing that slides on the splines just like the cassette
does but the outer ring of that bearing does not touch the cassette.

A cable attaches to a lever just like a bell crank lever and this lever
pushes against the outer ring. There is a ratchet mechanism in the
shifter just like there is today, you can actually build it to be
compatible with a standard shifter matching the number of cogs on the
cassette. A 2nd lever moves the upper arm of the derailer to ease the
chain onto the next cog when the cassette moves sideways for a gear
shift. The linkage can and probably should be fixed but adjustable so
you can use anything from corn-cob to mountain cassette.

The linkage can also be used to veer the derailer slightly sideways
during shifts for additional shifting speed. The trick is that this
veer
is very temporary and under load the chain always runs straight,
providing for a much better chain lifetime and the option to use
o-ringed chains.

The splines can get dirty on MTB so there may need to be bellows around
that just like there are on universal joints on cars, especially those
for offroad use. Making the freehub body even longer would
alternatively
allow sliding tubes to protect the splines.

Yet another embodiment would be to have the whole cassette movement
assembly inside the hub where it is better protected against the
elements. You cuold make it so that the freehub body is normal size and
comes out of the hub on a piston. That would be a much cleaner
solution.

As can easily be seen there wouldn't be too many additional things and
the cost difference can be more than an order of magnitude lower than a
Rohloff install. Well under $100. But ... quelle horreur ... this does
add a couple of ounces to the weight of the bike and might cause you to
arrive at the destination two seconds late.

Draw it out, Joerg.


The description above is clear enough. If you've ever studied patents
you should understand and be able to picture it in your mind. Besides,
my 3D drawing capability is pretty appalling, I leave that to drafting
departments or MEs.

The "draw it out" advice is not for my benefit. It's for yours.


Why? People skilled in the art will understand the description just as
well. They can put it together in their mind just as I can.

--
Regards, Joerg

http://www.analogconsultants.com/

On Friday, April 29, 2016 at 2:20:02 AM UTC-7, Rolf Mantel wrote:
Am 29.04.2016 um 06:11 schrieb jbeattie:
On Thursday, April 28, 2016 at 8:30:54 AM UTC-7, Frank Krygowski wrote:
snip

The issue isn't the single side axle support. I once owned a
recumbent trike whose front axles were supported only on the inboard
side.

What is the purpose of that design?

Why are cars designed with one-sided axle support? Whenever the wheels
are on the outside of a vehicle, one-sided axle support is a lot easier
to implement than two-sided axle support. So all trike I know have
one-sided axle support; typically you can take standard bicycle wheels
and 'only' increase the size of the axle by a few mm (I believe mine had
a Sachs drum brake wheel with different bearings so that a 10mm axle
could fit through it).

Good points, and probably a requirement for a trike, but I never saw the value on a front shock fork except as a novelty. I guess I'm also just nervous about unsupported axle ends on bikes, which at least seem to have a greater potential to bend.

-- Jay Beattie.

On 4/29/2016 9:23 AM, jbeattie wrote:
On Friday, April 29, 2016 at 2:20:02 AM UTC-7, Rolf Mantel wrote:
Am 29.04.2016 um 06:11 schrieb jbeattie:
On Thursday, April 28, 2016 at 8:30:54 AM UTC-7, Frank Krygowski wrote:
snip

The issue isn't the single side axle support. I once owned a
recumbent trike whose front axles were supported only on the inboard
side.

What is the purpose of that design?

Why are cars designed with one-sided axle support? Whenever the wheels
are on the outside of a vehicle, one-sided axle support is a lot easier
to implement than two-sided axle support. So all trike I know have
one-sided axle support; typically you can take standard bicycle wheels
and 'only' increase the size of the axle by a few mm (I believe mine had
a Sachs drum brake wheel with different bearings so that a 10mm axle
could fit through it).

Good points, and probably a requirement for a trike, but I never saw the value on a front shock fork except as a novelty. I guess I'm also just nervous about unsupported axle ends on bikes, which at least seem to have a greater potential to bend.

-- Jay Beattie.


I have no desire to own two wheeler with single side mounted
wheel but it's not new or untested:

http://www.vespa.com/en_EN/Heritage.html

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

On 4/28/2016 12:21 PM, Joerg wrote:
On 2016-04-28 08:19, Frank Krygowski wrote:
On 4/28/2016 9:50 AM, Joerg wrote:
On 2016-04-27 16:13, Frank Krygowski wrote:
On 4/27/2016 4:42 PM, Joerg wrote:
On 2016-04-25 12:38, Frank Krygowski wrote:

The real reason cars moved to hydraulic brakes is completely
irrelevant to
cyclists. Before hydraulics, cars used various mechanical
linkages to
activate brakes. The problem was the great difficulty of keeping the
left
and right side braking forces suitably equal. It was far to easy to
have
a brake microscopically misadjusted, and have it pull violently
left or
right under hard braking. Hydraulics cured that, since the pressure
in the
system is the same on the left or right sides.


Wire operated brakes can be auto-calibrated just as easily...

Oh? Left vs. right? How?


Picture a short rod. Actuating cable pulls in the center, lines to the
brake are connected to each side.

And if left & right cable friction or lever friction are slightly
different?


That means you've either damaged them or were sloppy on maintenance.

If you say so, Joerg. But in real life, changes in friction happen in
mechanical systems. As Ian has amply demonstrated, they happen even in
dead-simple systems.

And regarding "sloppy maintenance," how often have you had to adjust the
left-to-right balance on the hydraulic brakes on your SUV? I suspect
that it's zero. It's certainly been zero for me on every car I owned.
Hydraulic brakes don't need that kind of maintenance; the balance is
built into the physics of the system.

For contrast, here's a video on how to adjust a mechanical brake set:
http://vehicle-maintenance.wonderhow...l-ford-394596/

Note that the main objective is to get even braking on all four wheels.
And most guys with Model As have replaced the mechanical brakes with
hydraulics, for that very reason. Try looking it up. (Disclosu One
of my best friends is president of a Model A club. I gave him the Model
A owner's manual that I used to own.)

I am a checklist kind of guy when it comes to vehicles and other
important things. Among several things I test the function of the hand
brake before every ride in a car, wether mine, my wife's or any other.
Why do you think I never notice any veer when checking the
cable-actuated hand brake?

Probably because those operate on the rear wheels. The situations
analogous to a bike's front vs. rear brake. Heavy braking on the rear
doesn't cause swerving unless you go into a full skid.

An easy way to visualize it is that the mass of the vehicle is sort of
hanging on the rear contact patch (or patches), analogous to a yardstick
hanging vertically from a nail at its top end.

Heavy braking on the front has the vehicle sort of balancing on the
front contact patch or patches, analogous to balancing a yardstick on a
table. As soon as the center of mass gets out of alignment with the
balance point, rotation happens. And with two non-hydraulic front
brakes, it's very likely that one side is providing more resistance than
the other, meaning that "balance point" is not in line with the center
of mass.

Hint: Both of our vehicles are around 20 years old and _never_ needed
any veer-related adjustment in those cables. I doubt that there even is
such an adjustment option anymore because the automotive industry has
solved that problem many decades ago.

The automotive industry changed to hydraulic brakes decades ago, and put
the parking brakes on the rear wheels decades ago. Once again, you seem
to be claiming that you know more than every mechanical engineer in the
world, and you justify that by claim by citing experiences that no other
person seems to have had.

--
- Frank Krygowski