replacing center pull brakes with direct pull ones ?

Tom Kunich

"jim beam" <spamvortex@bad.example.net> wrote in message
news:0IadnYgxOaqx4cHVnZ2dnUVZ_q7inZ2d@speakeasy.net...
> Tom Kunich wrote:
>> "jim beam" <spamvortex@bad.example.net> wrote in message
>> news4GdnZ9LDJWv-8HVnZ2dnUVZ_tninZ2d@speakeasy.net...
>>>
>>> no timmy, you're just mathematically challenged. "linear pull" brakes
>>> are an improvement because the mechanical advantage stays essentially
>>> the same during operation, unlike cantilevers where the m.a. drops. we
>>> went all through this just a few weeks ago.
>>
>> Cantilevers work so badly I just don't see how anyone ever was able to
>> use them.
>
> so, when timmy the retard writes: "They were not designed to make braking
> better.", do you think he's correct?

Actually Tim is actually a bicyclist. And one that could ride you into the
ground any day of the week. I'd say that his farts are smarter than your
most intelligent responses.

Michael Press

In article
<4cbc1d99-476b-4f62-b998-7692b6f63610@26g2000hsk.googlegroups.com>,
Woland99 <woland99@gmail.com> wrote:

> Howdy - I am working on friends bike - it is an old MTB with center
> pull brakes.
> Old brakes seem serviceable. Should I attempt to put direct pull
> brakes on it?
> What are advantages of such move (if any)? If I understand Sheldon
> correctly
> I would need new set of levers too?

The current brakes can be overhauled to a state of perfection.
New cables and cable housing.
Cut the cable housing square by cutting it with old cable inside.

Disassemble the brakes, clean, lubricate, and reassemble.
I recommend not cleaning with solvent because some solvent
remains and compromises the new lubricant. I clean small parts
with mineral oil and a toothbrush then wipe them clean.
(I particularly like the smell of mineral oil in the morning.)

When reassembling, cut the cable housing to the correct length
and do not kink the housing.

Lubricate the cable before threading it into the housing.

Install ferrules where they are called for
and DO NOT install ferrules where they are not called for:
at the levers and at the brakes. With center pull brakes
the cable stops may or may not take ferrules. Try to fit
a ferrule to the cable stop, and if it does not fit, do
not use it.

New aero levers can be beneficial as well as looking cool.

After fitting the cable runs and before securing the cable
to the brakes, haul the cable with all the force you can
muster, thus seating in the cable run and preventing
"cable stretch."

Kool-stop salmon colored pads.

Your friend will consider you a wizard.

--
Michael Press

Tim McNamara

In article <aZWdnYPeo7I4rcHVnZ2dnUVZ_gednZ2d@earthlink.com>,
"Tom Kunich" <cyclintom@yahoo. com> wrote:

> "Tim McNamara" <timmcn@bitstream.net> wrote in message
> news:timmcn-490191.17031020062008@news.iphouse.com...
> >
> > (Other things that fall into the same situation are cassette hubs,
> > cartridge bottom brackets, threadless headsets- all of which reduce
> > labor at the factory and save money, allowing greater profit
> > margins or cheaper price points).
>
> Cassette hubs greatly increased the reliability of the rear axles on
> bike with more than 7 speeds. Probably even for 7-speed bikes as
> well. You almost never see a broken axle any more.

That is indeed a benefit for cyclists, but the initial impetus of the
cassette hub was to speed up assembly lines. OTOH, I've never bent or
broken one of my Bullseye or Phil Wood axles- even the 135 mm freewheel
hub under my 215 lb weight plus luggage. I broke my share of standard
freewheel axles, though.

Shimano very smartly attended to the needs of mass producers which gave
them huge OEM market share- killing Sun Tour and nearly killing
Campagnolo in the process- both in component design for fast assembly,
simplifying bike construction and and bulk packaging for factories.
Campy used to ship components to factories in those little retail boxes
they come in when you buy them at the bike shop...

> It isn't clear to me how to accept cartridge bottom brackets.
> Certainly the lowest quality bearings are better than most of the
> crappy cone bearings that were misadjusted most of the time. Though
> there probably was no advantage to properly lubricated and adjusted
> bearings.

There were advantages to properly lubricated and adjusted bottom bracket
bearings. One was rebuild-ability; another was larger ball bearings
providing for a more durable mechanism.

> As I pointed out - I came off very hard a month ago (first time in 20
> years of riding). Somehow my foot popped out of the inside pedal on a
> 30 mph downhill ride and went into the front wheel breaking off the
> fork. I was in the hospital all day while they waited to see if I had
> any symptoms of head injury - which I didn't.
>
> The next day I recovered my bike from a friend's garage, took it home
> and in 30 minutes (I had a spare carbon fork) I had totally replaced
> the fork and the bike was ready to ride again. I've put in 500 miles
> on that bike since then. So while I LIKE the old fashion threaded
> headsets I can see certain advantages to a threadless.

I don't, I think the threadless headset as it exists now is a design
that can go away. It's obviously "good enough" and maybe that's all
that is necessary.

Please note I am not stating that there are no benefits to cyclists in
these designs- just that the primary impetus for the designs was on the
supply side. Benefits to the consumer- which are often equivocal if
looked at critically- are incidental.

jim beam

Tom Kunich wrote:
> "jim beam" <spamvortex@bad.example.net> wrote in message
> news:0IadnYgxOaqx4cHVnZ2dnUVZ_q7inZ2d@speakeasy.net...
>> Tom Kunich wrote:
>>> "jim beam" <spamvortex@bad.example.net> wrote in message
>>> news4GdnZ9LDJWv-8HVnZ2dnUVZ_tninZ2d@speakeasy.net...
>>>>
>>>> no timmy, you're just mathematically challenged. "linear pull"
>>>> brakes are an improvement because the mechanical advantage stays
>>>> essentially the same during operation, unlike cantilevers where the
>>>> m.a. drops. we went all through this just a few weeks ago.
>>>
>>> Cantilevers work so badly I just don't see how anyone ever was able
>>> to use them.
>>
>> so, when timmy the retard writes: "They were not designed to make
>> braking better.", do you think he's correct?
>
> Actually Tim is actually a bicyclist.

actually actually? idiot.


> And one that could ride you into
> the ground any day of the week.

dumb-ass - you have no idea what my racing history is.


> I'd say that his farts are smarter than
> your most intelligent responses.
>

so you had no interest in the facts, you were just looking for a pissing
match. what a fool.

JG

Gentlemen,
the change in mechanical advantage of a cantilever brake (It's not
necessarily a reduction) between the point where the pads first touch
the rim and full pad squishing, cable stretching, tube twisting,
caliper bending glory is pretty inconseqential. Actually figuring out
what it is, is difficult.

JG

jim beam

JG wrote:
> Gentlemen,
> the change in mechanical advantage of a cantilever brake (It's not
> necessarily a reduction) between the point where the pads first touch
> the rim and full pad squishing, cable stretching, tube twisting,
> caliper bending glory is pretty inconseqential.

properly executed, and assuming no pad wear, that's correct. however,
if you're on a muddy descent where pad wear can be dramatic, or
suffering from fade, where you need all the force application you can
get, you can't ignore these things.



> Actually figuring out
> what it is, is difficult.

do you have a protractor? or even a ruler? all you need after that are
some trig functions.

_

On Sat, 21 Jun 2008 09:29:07 -0700 (PDT), JG wrote:

> Gentlemen,
> the change in mechanical advantage of a cantilever brake (It's not
> necessarily a reduction) between the point where the pads first touch
> the rim and full pad squishing, cable stretching, tube twisting,
> caliper bending glory is pretty inconseqential. Actually figuring out
> what it is, is difficult.
>

And further, it doesn't matter.

As long as the brake pads can be squeezed aginst the rim enough to lock the
wheel, and as long as there is a sufficient variation of engagement between
a gentle slowing and a full lock, most humans - any who are at all smarter
than flatulence, for instance - can moderate the action of their hands to
create the desired effect. It's not as though there is only a single force
available, nor indeed a single mechanical advantage at the brake lever.

landotter

On Jun 21, 11:29*am, JG <j...@cox.net> wrote:
> Gentlemen,
> the change in mechanical advantage of a cantilever brake (It's not
> necessarily a reduction) between the point where the pads first touch
> the rim and full pad squishing, cable stretching, tube twisting,
> caliper bending glory is pretty inconseqential. *Actually figuring out
> what it is, is difficult.
>

This is a slide rule measuring contest...you in?

A Muzi

jim beam wrote:
> Tim McNamara wrote:
>> In article
>> <f9d4aa2b-1769-43ec-aa16-237ef2e03e44@e53g2000hsa.googlegroups.com>,
>> Woland99 <woland99@gmail.com> wrote:
>>
>>> On Jun 20, 8:30 am, jim beam <spamvor...@bad.example.net> wrote:
>>>> Colin MacDonald wrote:
>>>>> On 20 Jun, 06:12, Woland99 <wolan...@gmail.com> wrote:
>>>>>> Howdy - I am working on friends bike - it is an old MTB with
>>>>>> center pull brakes. Old brakes seem serviceable. Should I attempt
>>>>>> to put direct pull brakes on it? What are advantages of such move
>>>>>> (if any)? ?If I understand Sheldon correctly I would need new set
>>>>>> of levers too?
>>>>> If the existing brakes work then there's no really good reason to
>>>>> change them - cantilever brakes are fine for most situations. But
>>>>> if you do change the brakes then yes, you will need to change the
>>>>> levers as well.
>>>> not necessarily - depends on whether they're mtb direct pulls, or
>>>> road. they have different leverage ratios.
>>> OK - I should have said "replacing cantilever brakes with direct pull
>>> ones". The reason I thought about doing it is that my friend was
>>> complaining that old brakes did not work very well. Do I understand
>>> it correctly that you can exert more force on rims using direct pull
>>> brakes?
>>
>> That's a definite "maybe." We should all bear in mind that V brakes
>> were designed manufacturing efficiency- they eliminate the need for a
>> cable housing stop above the brake, therefore making it easier to
>> build suspension forks and full suspension mountain bikes. They were
>> not designed to make braking better. Any benefits for the rider are
>> accidental. Unfortunately the bike rags didn't understand this and
>> blathered on about better braking so that it is now part of the lore
>> and myth of bicycling.
>
> no timmy, you're just mathematically challenged. "linear pull" brakes
> are an improvement because the mechanical advantage stays essentially
> the same during operation, unlike cantilevers where the m.a. drops. we
> went all through this just a few weeks ago.
>
>
>>
>> (Other things that fall into the same situation are cassette hubs,
>> cartridge bottom brackets, threadless headsets- all of which reduce
>> labor at the factory and save money, allowing greater profit margins
>> or cheaper price points).
>
> paranoid bull.

Meanwhile, back here in reality, modern brakes chew through modern thin
rims on a regular basis. (loud bang, 20~30cm of rim section goes flying)
This was once a rare phenomenon before 'improvement'.

--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971
** Posted from http://www.teranews.com **

jim beam

A Muzi wrote:
> jim beam wrote:
>> Tim McNamara wrote:
>>> In article
>>> <f9d4aa2b-1769-43ec-aa16-237ef2e03e44@e53g2000hsa.googlegroups.com>,
>>> Woland99 <woland99@gmail.com> wrote:
>>>
>>>> On Jun 20, 8:30 am, jim beam <spamvor...@bad.example.net> wrote:
>>>>> Colin MacDonald wrote:
>>>>>> On 20 Jun, 06:12, Woland99 <wolan...@gmail.com> wrote:
>>>>>>> Howdy - I am working on friends bike - it is an old MTB with
>>>>>>> center pull brakes. Old brakes seem serviceable. Should I attempt
>>>>>>> to put direct pull brakes on it? What are advantages of such move
>>>>>>> (if any)? ?If I understand Sheldon correctly I would need new set
>>>>>>> of levers too?
>>>>>> If the existing brakes work then there's no really good reason to
>>>>>> change them - cantilever brakes are fine for most situations. But
>>>>>> if you do change the brakes then yes, you will need to change the
>>>>>> levers as well.
>>>>> not necessarily - depends on whether they're mtb direct pulls, or
>>>>> road. they have different leverage ratios.
>>>> OK - I should have said "replacing cantilever brakes with direct
>>>> pull ones". The reason I thought about doing it is that my friend
>>>> was complaining that old brakes did not work very well. Do I
>>>> understand it correctly that you can exert more force on rims using
>>>> direct pull brakes?
>>>
>>> That's a definite "maybe." We should all bear in mind that V brakes
>>> were designed manufacturing efficiency- they eliminate the need for a
>>> cable housing stop above the brake, therefore making it easier to
>>> build suspension forks and full suspension mountain bikes. They were
>>> not designed to make braking better. Any benefits for the rider are
>>> accidental. Unfortunately the bike rags didn't understand this and
>>> blathered on about better braking so that it is now part of the lore
>>> and myth of bicycling.
>>
>> no timmy, you're just mathematically challenged. "linear pull" brakes
>> are an improvement because the mechanical advantage stays essentially
>> the same during operation, unlike cantilevers where the m.a. drops.
>> we went all through this just a few weeks ago.
>>
>>
>>>
>>> (Other things that fall into the same situation are cassette hubs,
>>> cartridge bottom brackets, threadless headsets- all of which reduce
>>> labor at the factory and save money, allowing greater profit margins
>>> or cheaper price points).
>>
>> paranoid bull.
>
> Meanwhile, back here in reality, modern brakes chew through modern thin
> rims on a regular basis. (loud bang, 20~30cm of rim section goes flying)
> This was once a rare phenomenon before 'improvement'.

well, /that/ is not going to happen at all on tubular rims!!!

imo, this situation, while impossible to eliminate completely, is much
exacerbated by the modern objective of toe-in on brake pads. back in
the old days, pads were set parallel to the rim, they didn't trap too
much grit, if at all, and everything was dandy. then came shimano's
fixed toe-in with their dual pivot brakes, and suddenly, everybody is
riding around with trapped grit stuck in their brake pads, and thus, rim
skimming happens every time a brake is used. no wonder they didn't last.

now, we're in the world of orbital brake pad mounting posts and we can
set our pads back to zero toe, much reduce grit trapping, and thus, much
reduce rim wear.

about the only reason i ever used campy brakes/shifters was because they
never subscribed to the fixed brake toe of shimano and went with orbital
pad mounts from the first day of dual pivot. once shimano went orbital,
and sick of breaking shifter mechanisms, i when full shimano and zero
toe. works great.

jim beam

jim beam wrote:
> A Muzi wrote:
>> jim beam wrote:
>>> Tim McNamara wrote:
>>>> In article
>>>> <f9d4aa2b-1769-43ec-aa16-237ef2e03e44@e53g2000hsa.googlegroups.com>,
>>>> Woland99 <woland99@gmail.com> wrote:
>>>>
>>>>> On Jun 20, 8:30 am, jim beam <spamvor...@bad.example.net> wrote:
>>>>>> Colin MacDonald wrote:
>>>>>>> On 20 Jun, 06:12, Woland99 <wolan...@gmail.com> wrote:
>>>>>>>> Howdy - I am working on friends bike - it is an old MTB with
>>>>>>>> center pull brakes. Old brakes seem serviceable. Should I
>>>>>>>> attempt to put direct pull brakes on it? What are advantages of
>>>>>>>> such move (if any)? ?If I understand Sheldon correctly I would
>>>>>>>> need new set of levers too?
>>>>>>> If the existing brakes work then there's no really good reason to
>>>>>>> change them - cantilever brakes are fine for most situations.
>>>>>>> But if you do change the brakes then yes, you will need to change
>>>>>>> the levers as well.
>>>>>> not necessarily - depends on whether they're mtb direct pulls, or
>>>>>> road. they have different leverage ratios.
>>>>> OK - I should have said "replacing cantilever brakes with direct
>>>>> pull ones". The reason I thought about doing it is that my friend
>>>>> was complaining that old brakes did not work very well. Do I
>>>>> understand it correctly that you can exert more force on rims using
>>>>> direct pull brakes?
>>>>
>>>> That's a definite "maybe." We should all bear in mind that V brakes
>>>> were designed manufacturing efficiency- they eliminate the need for
>>>> a cable housing stop above the brake, therefore making it easier to
>>>> build suspension forks and full suspension mountain bikes. They
>>>> were not designed to make braking better. Any benefits for the
>>>> rider are accidental. Unfortunately the bike rags didn't understand
>>>> this and blathered on about better braking so that it is now part of
>>>> the lore and myth of bicycling.
>>>
>>> no timmy, you're just mathematically challenged. "linear pull"
>>> brakes are an improvement because the mechanical advantage stays
>>> essentially the same during operation, unlike cantilevers where the
>>> m.a. drops. we went all through this just a few weeks ago.
>>>
>>>
>>>>
>>>> (Other things that fall into the same situation are cassette hubs,
>>>> cartridge bottom brackets, threadless headsets- all of which reduce
>>>> labor at the factory and save money, allowing greater profit margins
>>>> or cheaper price points).
>>>
>>> paranoid bull.
>>
>> Meanwhile, back here in reality, modern brakes chew through modern
>> thin rims on a regular basis. (loud bang, 20~30cm of rim section goes
>> flying)
>> This was once a rare phenomenon before 'improvement'.
>
> well, /that/ is not going to happen at all on tubular rims!!!
>
> imo, this situation, while impossible to eliminate completely, is much
> exacerbated by the modern objective of toe-in on brake pads. back in
> the old days, pads were set parallel to the rim, they didn't trap too
> much grit, if at all, and everything was dandy. then came shimano's
> fixed toe-in with their dual pivot brakes, and suddenly, everybody is
> riding around with trapped grit stuck in their brake pads, and thus, rim
> skimming happens every time a brake is used. no wonder they didn't last.
>
> now, we're in the world of orbital brake pad mounting posts and we can
> set our pads back to zero toe, much reduce grit trapping, and thus, much
> reduce rim wear.
>
> about the only reason i ever used campy brakes/shifters was because they
> never subscribed to the fixed brake toe of shimano and went with orbital
> pad mounts from the first day of dual pivot. once shimano went orbital,
> and sick of breaking

campy

> shifter mechanisms, i when full shimano and zero
> toe. works great.

A Muzi

> "jim beam" <spamvortex@bad.example.net> wrote
>> no timmy, you're just mathematically challenged. "linear pull" brakes
>> are an improvement because the mechanical advantage stays essentially
>> the same during operation, unlike cantilevers where the m.a. drops.
>> we went all through this just a few weeks ago.

Tom Kunich wrote:
> Cantilevers work so badly I just don't see how anyone ever was able to
> use them.


You'd be surprised how many touring bikes change from V to cantilever.

--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971
** Posted from http://www.teranews.com **

Tom Kunich

"A Muzi" <am@yellowjersey.org> wrote in message
news:b5728$485d476c$13197@news.teranews.com...
>> "jim beam" <spamvortex@bad.example.net> wrote
>>> no timmy, you're just mathematically challenged. "linear pull" brakes
>>> are an improvement because the mechanical advantage stays essentially
>>> the same during operation, unlike cantilevers where the m.a. drops. we
>>> went all through this just a few weeks ago.
>
> Tom Kunich wrote:
>> Cantilevers work so badly I just don't see how anyone ever was able to
>> use them.
>
> You'd be surprised how many touring bikes change from V to cantilever.

No I wouldn't. V-brakes are set so close to the rim that you must have a
perfectly straight wheel for them not to drag. If you have cantilevers they
are much further away from the rims and the braking effort difference is
hardly noticeable after the first application.

And V-brakes are far too sensitive as well. I prefer having to pull on the
levers a little harder without locking up my front wheel...

landotter

On Jun 21, 1:44*pm, "Tom Kunich" <cyclintom@yahoo. com> wrote:
> "A Muzi" <a...@yellowjersey.org> wrote in message
>
> news:b5728$485d476c$13197@news.teranews.com...
>
> >> "jim beam" <spamvor...@bad.example.net> wrote
> >>> no timmy, you're just mathematically challenged. *"linear pull" brakes
> >>> are an improvement because the mechanical advantage stays essentially
> >>> the same during operation, unlike cantilevers where the m.a. drops. *we
> >>> went all through this just a few weeks ago.
>
> > Tom Kunich wrote:
> >> Cantilevers work so badly I just don't see how anyone ever was able to
> >> use them.
>
> > You'd be surprised how many touring bikes change from V to cantilever.
>
> No I wouldn't. V-brakes are set so close to the rim that you must have a
> perfectly straight wheel for them not to drag. If you have cantilevers they
> are much further away from the rims and the braking effort difference is
> hardly noticeable after the first application.
>
> And V-brakes are far too sensitive as well. I prefer having to pull on the
> levers a little harder without locking up my front wheel...

Set the spring tension all the way in, balance the arms by loosening
one or the other. Add some toe-in and you're in business. Great fuss-
free braking with decent modulation. Perhaps you've only tried vees
set up with the pads parallel on machined rims and the tension set too
low?

As far as keeping the wheels true--a properly tensioned wheel
shouldn't go out of true under normal use. It shouldn't be a reason to
choose a braking system.