replacing center pull brakes with direct pull ones ?



W

Woland99

Guest
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?
 
Woland99 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?


you would need a new frame too, as the pivots are in the wrong place (u
brake pivots are above the rim, V-brake pivots below. Diameter can be
different too)


--
/Marten

info(apestaartje)m-gineering(punt)nl
 
On Jun 20, 1:06 am, M-gineering <[email protected]> wrote:
> Woland99 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?

>
> you would need a new frame too, as the pivots are in the wrong place (u
> brake pivots are above the rim, V-brake pivots below. Diameter can be
> different too)
>
> --
> /Marten
>
> info(apestaartje)m-gineering(punt)nl


Hmmm... orginal brakes are traditional center pull - not u-brakes
so pivots are below the rims - just like in v-brakes. But i did
not check diameters yet - I assumed those were standarized.
 
Woland99 wrote:
> On Jun 20, 1:06 am, M-gineering <[email protected]> wrote:
>> Woland99 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?

>> you would need a new frame too, as the pivots are in the wrong place (u
>> brake pivots are above the rim, V-brake pivots below. Diameter can be
>> different too)
>>
>> --
>> /Marten
>>
>> info(apestaartje)m-gineering(punt)nl

>
> Hmmm... orginal brakes are traditional center pull - not u-brakes
> so pivots are below the rims - just like in v-brakes. But i did
> not check diameters yet - I assumed those were standarized.



Ah, semantics. It's more usual to call them cantilevers. These are
interchangable

--
/Marten

info(apestaartje)m-gineering(punt)nl
 
On 20 Jun, 06:12, Woland99 <[email protected]> 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.

Colin
 
Colin MacDonald wrote:
> On 20 Jun, 06:12, Woland99 <[email protected]> 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.
 
On Jun 20, 8:30 am, jim beam <[email protected]> wrote:
> Colin MacDonald wrote:
> > On 20 Jun, 06:12, Woland99 <[email protected]> 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?

I think that the new ones I got are MTB direct pulls. These are
Avid Single Digit 5.
 
In article <f9d4aa2b-1769-43ec-aa16-237ef2e03e44@e53g2000hsa.googlegroups.com>,
Woland99 <[email protected]> wrote:
>On Jun 20, 8:30 am, jim beam <[email protected]> wrote:
>> Colin MacDonald wrote:
>> 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.


Cantilever brakes take more work to setup properly, but once
that's done they work as well as any in my experience. See
Sheldon Brown's page on cantilever brakes.

>Do I understand it correctly that you can exert more force on rims
>using direct pull brakes?


No, they are just a lot easier to setup.

_ Booker C. Bense
 
On Thu, 19 Jun 2008 22:12:18 -0700 (PDT), Woland99
<[email protected]> may have said:

>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?


It's very likely that a new set of pads and a little attention to
adjustment will make the existing brakes as effective as they need to
be. Although you can mount direct-pull brakes in place of cantis,
unless you replace the levers at the same time, you'll find that the
brake adjustment gets very touchy, the need for proper wheel truing
gets even more critical, the hand lever travel gets quite long, and it
may become distressingly easy to unintentionally lock the brakes.

Before doing all that, I'd try swapping to a new set of brake pads.
Make sure that you check the rims for wear first, though. If the bike
has a lot of miles, and the rims are aluminum, then the sidewalls of
the rims may be worn enough that it may be new wheel time. Steel rims
generally don't wear enough to worry about, but braking is nowhere
near as effective in wet conditions with a steel rim, either.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.
 
On Jun 20, 10:38 am, Woland99 <[email protected]> wrote:
> On Jun 20, 8:30 am, jim beam <[email protected]> wrote:
>
>
>
> > Colin MacDonald wrote:
> > > On 20 Jun, 06:12, Woland99 <[email protected]> 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?


AFAIK, you lose mechanical advantage with cantis as the lever is
pulled towards the handlebars. That said--they can be set up to brake
nicely. The high mechanical advantage of linear pull brakes comes at
the disadvantage of needing to keep the brake pads very close to the
rim and thus the wheels very true.

>
> I think that the new ones I got are MTB direct pulls. These are
> Avid Single Digit 5.


You'll need new levers that pull the appropriate amount of cable.
About $15USD for some decent models by Tektro or a suitable
equivalent.
 
In article
<f9d4aa2b-1769-43ec-aa16-237ef2e03e44@e53g2000hsa.googlegroups.com>,
Woland99 <[email protected]> wrote:

> On Jun 20, 8:30 am, jim beam <[email protected]> wrote:
> > Colin MacDonald wrote:
> > > On 20 Jun, 06:12, Woland99 <[email protected]> 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.

(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).
 
"Tim McNamara" <[email protected]> wrote in message
news:[email protected]...
>
> (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.

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.

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.
 
Tim McNamara wrote:
> In article
> <f9d4aa2b-1769-43ec-aa16-237ef2e03e44@e53g2000hsa.googlegroups.com>,
> Woland99 <[email protected]> wrote:
>
>> On Jun 20, 8:30 am, jim beam <[email protected]> wrote:
>>> Colin MacDonald wrote:
>>>> On 20 Jun, 06:12, Woland99 <[email protected]> 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.
 
"jim beam" <[email protected]> wrote in message
news:eek:[email protected]...
>
> 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.
 
Tom Kunich wrote:
> "jim beam" <[email protected]> wrote in message
> news:eek:[email protected]...
>>
>> 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?
 
"jim beam" <[email protected]> wrote in message
news:[email protected]...
> Tom Kunich wrote:
>> "jim beam" <[email protected]> wrote in message
>> news:eek:[email protected]...
>>>
>>> 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.
 
In article
<[email protected]>,
Woland99 <[email protected]> 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
 
In article <[email protected]>,
"Tom Kunich" <cyclintom@yahoo. com> wrote:

> "Tim McNamara" <[email protected]> wrote in message
> news:[email protected]...
> >
> > (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.
 
Tom Kunich wrote:
> "jim beam" <[email protected]> wrote in message
> news:[email protected]...
>> Tom Kunich wrote:
>>> "jim beam" <[email protected]> wrote in message
>>> news:eek:[email protected]...
>>>>
>>>> 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.
 
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