Do I want disc brakes?

On 15 Lip, 11:51, Chalo wrote:

I think discs will more than likely be a letdown for you. *They have
more points of failure and not surprisingly, more frequent failures
(as defined by problems requiring some mechanical attention rather
than those that leave you walking).

Somehwat true. Hydraulics may need more maintenence, however i have
hydros on all my bikes and still (2 years of riding) none of them
requires 'messy' mainentence, just pad replacement.

Compared to rim brakes, they are
more likely to drag, make noise, or get bungled in the course of
routine bike parking and storage. *Hydraulics are a nuisance to
maintain and generally not field-serviceable.

Generally - people ride hydraulics in places where rim brakes would
simply not work. Including downhilling this style:
http://www.youtube.com/watch?v=4ctDA2jhiYQ

If disks somehow survive this - unfazed, then they do not have
maintenence problems.

Mechanical discs are just as demanding to set up as rim brakes.

That's good right?

But they require more maintenance and
intervention than rim brakes and a whole lot more than drums.

Drums - dunno. Rim brakes - hell no. setting up disks takes approx 30
seconds.

Though
discs are plenty strong for general use, they can't dissipate as much
continuous braking energy as good rim brakes.

Somewhat true/

And while they are much
cleaner than rim brakes, they are not nearly as clean as drum or
coaster brakes.

Drum brakes would boil on some places where disks are used.

Disc brakes offer no power advantage,

False.

no weight advantage

True

and no reliability advantage.

False

All you get for your trouble and expense is
improved tolerance of filth and rim damage and maybe nicer lever feel
(if you're lucky).

And better braking power (203mm rotors rock, 225mm rotors rock hard)
and much better brake feel, no danger of rim explosion due to wear,
lesser wheel trueness requirements, possibility to configure brake
strength by changing disc sizes, water resistance, snow resistance.
Pads usually last much longer.

Regards.

--
Adam Kadlubek

WhatsUp wrote:
I am used to rim brakes.

But I am in the market for a new bike, and the ones that interest me
come with disc brakes.

Do I want disc brakes?

Or should I limit my choice of bikes to those with rim brakes?

Most of my riding is on streets and urban dirt paths. I want the
ability to go off-road occassionally; but by off-road, I mean
relatively tame mountain trails, not downhill racing and jumps. In
any case, I do not anticipate biking in sloppy (wet) conditions.

I can wear through a rim in one winter if I'm riding enough. I'd rather
wear through some disc brake pads.

I've also done less maintenance on my disc brakes than I had on caliper
type brakes. I'm not saying that is the case for everyone but I doubt
it's as simple as saying discs require more maintenance. Furthermore,
disc brakes make mounting fenders a lot easier. I generally find the
issue of more or less braking power to be a red herring, as I don't
recall ever not having enough braking power with any brake. I certainly
have not had problems with my deore disc brakes on steep north shore mtb
rides, I can't imagine what problems a person would have on the terrain
you mention.

Adam Kadlubek wrote:

Generally - people ride hydraulics in places where rim brakes would
simply not work. Including downhilling this style: http://www.youtube.com/watch?v=4ctDA2jhiYQ

If disks somehow survive this - unfazed, then they do not have
maintenence problems.

Makes you wonder how poor Tomac and "Hairball" managed with only rim
brakes. They could have "rocked" the latest Mountain Cycle Pro-Stop 9-
inchers, but they didn't-- even though Mountain Bike Action thought
they were ultra rad.

http://www.youtube.com/watch?v=s99qM_tNo7U

Rim braked front wheels are stiffer and stronger due to better spoke
bracing angle, so in that regard they are better for the type of
riding you refer to.

But they require more maintenance and
intervention than rim brakes and a whole lot more than drums.

Drums - dunno. Rim brakes - hell no. setting up disks takes approx 30
seconds.

Um, no. I have them, I like them, and I've set them up. But just
attaching a rotor is the same size job as doing a V-brake swap, and
calipers often require shimming and/or centering lest you live with
"scrape scrape scrape scrape" until you go batty.

And while they are much
cleaner than rim brakes, they are not nearly as clean as drum or
coaster brakes.

Drum brakes would boil on some places where disks are used.

There's no "boil" with drums; they are all metal. Fade is the only
problem when they overheat (though it can certainly be a problem).
Arai drums are the heat-rejectingest bicycle brakes of any kind,
ever. No rim or disc can approach their continuous energy
dissipation.

All you get for your trouble and expense is
improved tolerance of filth and rim damage and maybe nicer lever feel
(if you're lucky).

And better braking power (203mm rotors rock, 225mm rotors rock hard)

Sorry, I weigh 350, used to weigh even more, and I have run bikes as
heavy as 500 lbs gross and pedal trike/trailers as heavy as 3200 lbs
gross. I have been in the position to evaluate braking power in
regimes where most folks have to guess. Hydraulic discs _feel_
powerful because of their aggressive onset, but rim brakes can have a
lot more real braking torque in them. They can keep delivering the
goods after an 8-inch hydro disc says "uncle".

and much better brake feel, no danger of rim explosion due to wear,
lesser wheel trueness requirements [...] water resistance, snow resistance.

I think this is the reiteration of what I said and you quoted above.

possibility to configure brake strength by changing disc sizes,

Given that a rim brake can be stronger (on a 26" or larger wheel at
least) I don't know how relevant this is. There are ways to weaken
the response of a rim brake if that's what you want.

Pads usually last much longer.

Not in my experience. My first set of Hayes disc pads burned down to
their backings in less than 20 miles of my usual hilly city riding.
The best replacements I have found (EBC Gold metallic pads) still
expire far sooner than rim brake pads. Only downhilling in wet
abrasive slurry has the potential to wreck rim brake pads as fast as
non-metallic disc pads disappear for me on clean streets.

Chalo

"nmp" wrote in message
...
JP wrote:

When I remove a wheel I have to deflate the tire to get it past the rim
brakes.

Er... You should be able to simply unhook the brake cable in such a way
that the brake "opens".

No, not my setup. I have a lever that changes the jaw opening but
not enough to get my chubby 700X30 past the brakes. Nothing unhooks.
(My wife's bike has the setup you describe)

Makes you wonder how poor Tomac and "Hairball" managed with only rim
brakes. *They could have "rocked" the latest Mountain Cycle Pro-Stop 9-
inchers, but they didn't-- even though Mountain Bike Action thought
they were ultra rad.

http://www.youtube.com/watch?v=s99qM_tNo7U

Rim braked front wheels are stiffer and stronger due to better spoke
bracing angle, so in that regard they are better for the type of
riding you refer to.

Makes you wonder why in most of the shots there they have discs.

Drums - dunno. Rim brakes - hell no. setting up disks takes approx 30
seconds.

Um, no. *I have them, I like them, and I've set them up. *But just
attaching a rotor is the same size job as doing a V-brake swap, and
calipers often require shimming and/or centering lest you live with
"scrape scrape scrape scrape" until you go batty.

Honestly - never had such problems (I used avid Juicy 7, Juicy 7,
shimano 575, and 485) unless I bent the disc in some sort of
catastrophic way. As for setting up - mounting a disk in 6 bolt BCD
takes some time. Shimano Centerlock are a 30 second job. Besides -
once disk is mounted you take it off only for replacement ( too worn,
or destroyed ). Adjusting the calipers themselves takes another 30-60
seconds. Hydros, require no real adjustments from there, up until pad
replacement. Unlike V-brakes which require constant attention and
readjustment as pads wear.

There's no "boil" with drums; they are all metal. *Fade is the only
problem when they overheat (though it can certainly be a problem).
Arai drums are the heat-rejectingest bicycle brakes of any kind,
ever. *No rim or disc can approach their continuous energy
dissipation.

A figure of speech, so to speak. That being said - drum brakes will
fade before discs. As for Arai drums - if they are _designed_ as a
heatsink for tandems, id expect them to perform just as well. Normal
brakes are designed for single bikes, so obviously they are not meant
for tandem drag brake.

Sorry, I weigh 350, used to weigh even more, and I have run bikes as
heavy as 500 lbs gross and pedal trike/trailers as heavy as 3200 lbs
gross. *I have been in the position to evaluate braking power in
regimes where most folks have to guess. *Hydraulic discs _feel_
powerful because of their aggressive onset, but rim brakes can have a
lot more real braking torque in them. *They can keep delivering the
goods after an 8-inch hydro disc says "uncle".

Sorry - I weigh 250lbs with 40 lbs of bike, and another 20 in
accesories. That is, say 300 lbs. 40 mph downhills have never been a
problem. neither were 10mile descents with brakes pretty much always
actuated.

On the other hand I had rim brakes say "uncle" on several occasions,
including no brakes on ice or in the rain or a blown off rim due to
road debris collected by the pads.

I think this is the reiteration of what I said and you quoted above.

Somewhat, hes

possibility to configure brake strength by changing disc sizes,

Given that a rim brake can be stronger (on a 26" or larger wheel at
least) I don't know how relevant this is. *There are ways to weaken
the response of a rim brake if that's what you want.

Weakening the rim brakes always comes at a cost of the brake feel. By
changing a disk from 225 to 140mm you get the same feel, just
different brake strength. I use 185mm front and 140mm back on my road
bike and I love that setup.
And 203mm disk is stronger then typical V-brake.

Pads usually last much longer.

Not in my experience. *My first set of Hayes disc pads burned down to
their backings in less than 20 miles of my usual hilly city riding.
The best replacements I have found (EBC Gold metallic pads) still
expire far sooner than rim brake pads. *Only downhilling in wet
abrasive slurry has the potential to wreck rim brake pads as fast as
non-metallic disc pads disappear for me on clean streets.

Once again, I have different experience here. V-brake pads last me
about 3-4 months, Disks up to a year, depending on the resin type.

Regards.
--
Adam Kadlubek

Per WhatsUp:
But I am in the market for a new bike, and the ones that interest me
come with disc brakes.

Do I want disc brakes?

Greater minds than mine will say "No Way Jose'"

But I *like* my disc brakes.

I even replaced my rear discs with rim brakes for awhile just
because the rear brake obviously doesn't need the braking power
or modulation that the front does.

Took about three days and I went back to the discs.


To wit:

- If I taco a wheel, the braking functionality lives on.

- When I ride into a rain shower, my braking power at the
wheel stays constant (don't get me wrong... the wheel might
skid all over the pavement.... but at least there's no issue
of nothing happening when I squeeze the levers) I've got
a front drum brake on my (very old) utility bike for that
reason.

- I find disc brakes less failure prone. I've crashed with
cantis, failed to notice that one of the pads had bent up to
where it rubbed the sidewall, and shortly thereafter blown that
tire.

Hydraulics, I've had problems with on really hot days
and/or going down extremely steep slopes: the fluid expands or
something, causing the break to lock up and one has to wait
it out until the fluid cools. There's also a PITA factor
when it comes time to replace the fluid.

Cable-operated Avids, I've never, ever had a problem with.

The only disc issue I can think of is oil: you get oil on
the disc (or some kid with emotional problems squirts some
on said disc while the bike's laying somewhere) and it's all
over. Happened to me once when my Rohloff hub was leaking
oil.

- The pads last longer. I hear stories of people wearing out
as set of rim pads on a single descent. The v-brake pads
I had on my utility bike didn't last a year. OTOH, I get
multi years out of a set of disc pads.

- Mud is not an issue. The noise that rim brakes make in mud
makes my skin crawl - and what it does to the rim isn't
pretty. No such issue with discs.

- My experience is that discs offer better modulation than
cable-operated rim brakes. Hydraulic discs == even better
modulation; but cable discs are still ahead.

- With disc brakes, wheels are no longer a consumable (i.e. the
walls of the rims never wear out).
--
PeteCresswell

On Wed, 15 Jul 2009 13:04:08 -0700 (PDT), Adam Kadlubek
wrote:

Makes you wonder how poor Tomac and "Hairball" managed with only rim
brakes. *They could have "rocked" the latest Mountain Cycle Pro-Stop 9-
inchers, but they didn't-- even though Mountain Bike Action thought
they were ultra rad.

http://www.youtube.com/watch?v=s99qM_tNo7U

Rim braked front wheels are stiffer and stronger due to better spoke
bracing angle, so in that regard they are better for the type of
riding you refer to.

Makes you wonder why in most of the shots there they have discs.

Because those are specialist downhill bikes that weigh 45 freeking pounds and
the excess weight of a disk doesn't matter. There is isn't a choice, for all
other types of riding there's a decision to be made.

Drums - dunno. Rim brakes - hell no. setting up disks takes approx 30
seconds.

Um, no. *I have them, I like them, and I've set them up. *But just
attaching a rotor is the same size job as doing a V-brake swap, and
calipers often require shimming and/or centering lest you live with
"scrape scrape scrape scrape" until you go batty.

Honestly - never had such problems (I used avid Juicy 7, Juicy 7,
shimano 575, and 485) unless I bent the disc in some sort of
catastrophic way. As for setting up - mounting a disk in 6 bolt BCD
takes some time. Shimano Centerlock are a 30 second job. Besides -
once disk is mounted you take it off only for replacement ( too worn,
or destroyed ). Adjusting the calipers themselves takes another 30-60
seconds. Hydros, require no real adjustments from there, up until pad
replacement. Unlike V-brakes which require constant attention and
readjustment as pads wear.

Readjusting a V brake means turning a screw you can do while riding. Without
letting go of the handlebars.

There's no "boil" with drums; they are all metal. *Fade is the only
problem when they overheat (though it can certainly be a problem).
Arai drums are the heat-rejectingest bicycle brakes of any kind,
ever. *No rim or disc can approach their continuous energy
dissipation.

A figure of speech, so to speak. That being said - drum brakes will
fade before discs. As for Arai drums - if they are _designed_ as a
heatsink for tandems, id expect them to perform just as well. Normal
brakes are designed for single bikes, so obviously they are not meant
for tandem drag brake.

Sorry, I weigh 350, used to weigh even more, and I have run bikes as
heavy as 500 lbs gross and pedal trike/trailers as heavy as 3200 lbs
gross. *I have been in the position to evaluate braking power in
regimes where most folks have to guess. *Hydraulic discs _feel_
powerful because of their aggressive onset, but rim brakes can have a
lot more real braking torque in them. *They can keep delivering the
goods after an 8-inch hydro disc says "uncle".

Sorry - I weigh 250lbs with 40 lbs of bike, and another 20 in
accesories. That is, say 300 lbs. 40 mph downhills have never been a
problem. neither were 10mile descents with brakes pretty much always
actuated.

Again, your motorless motorcycle has nothing to do with the way normal people
ride bikes. The twenty year old steel framed bike I ride to church and to pick
up groceries weighs twelve pounds less than that lump of yours.

The question wasn't about building a bike to fall down a mountain with, it was
about bike to ride, to go places. Places that require going up hills, without a
ski lift.

Your answer is about as wrong and in the same way as a cyclocrosser saying that
the OP should get canti's for the mud clearance with drop bar levers.

On Wed, 15 Jul 2009 09:12:15 -0700 (PDT), Jay Beattie
wrote:

On Jul 15, 8:23*am, landotter wrote:
On Jul 15, 3:28*am, WhatsUp wrote:

I am used to rim brakes.

But I am in the market for a new bike, and the ones that interest me
come with disc brakes.

Do I want disc brakes?

Or should I limit my choice of bikes to those with rim brakes?

Most of my riding is on streets and urban dirt paths. *I want the
ability to go off-road occassionally; but by off-road, I mean
relatively tame mountain trails, not downhill racing and jumps. *In
any case, I do not anticipate biking in sloppy (wet) conditions.

What kinda bike is it? If it's a mtb, you're pretty much stuck with
discs. Not the worst thing in the world as the cheaper cable operated
models by Hayes and Tektro have evolved beyond 100% suck (first
generation Deore anyone? Ugh)

I pretty much agree with Chalo, especially considering that you don't
ride in wet conditions.

Nothing feels as positive and modulates as well as a dual pivot, but I
am perfectly happy with the discs on my commuter. The only problem I
have had (after learning how to properly adjust them) was pad wear,
and the fact that I can dial them down and wear them out until the
return springs hit the rotors. In other words, if I am not paying
attention to wear, I can get myself in to trouble.

If I lived in Arizona or some other dry climate, I wouldn't bother
with them -- except on a tandem, where rim heat build up with two
large riders would be a problem, and unlike Chalo, I do not find drum
brakes that effective as a primary brake, but then maybe I have not
used a good drum brake in the past. -- Jay Beattie.

For the tandem get the Arai roller brake AND a good pair of clampers, V or dual
pivot.

On 15 Jul 2009 18:34:12 GMT, nmp wrote:

JP wrote:

When I remove a wheel I have to deflate the tire to get it past the rim
brakes.

Er... You should be able to simply unhook the brake cable in such a way
that the brake "opens".

Depends on the brake and the tire. When I had 32mm cross tires on an old road
bike I had to do that drill myself.

On 15 Jul 2009 21:39:46 GMT, nmp wrote:

JP wrote:

"nmp" wrote in message
...
JP wrote:

When I remove a wheel I have to deflate the tire to get it past the
rim brakes.

Er... You should be able to simply unhook the brake cable in such a way
that the brake "opens".

No, not my setup. I have a lever that changes the jaw opening but
not enough to get my chubby 700X30 past the brakes. Nothing unhooks.
(My wife's bike has the setup you describe)

I believe you of course - but now I wonder what kind of brakes you have.
You mentioned cantilever brakes. In my perhaps limited experience those
can always be unhooked. A lever to slightly open the brake calipers is
something I would associate with single or dual pivot road racing brakes.

A lot of canti pads will hang on the inside of the fork legs or stays limiting
how far they open even without the straddle cable. Run into that on cross bikes
all the time.