Are disc-brakes just a gimic?

Given that the tire rim itself functions as essentially an enormous disc
for "regular" brakes, what's the deal here....beyond adding $100 to $150
to the cost of a typical $500 model? Then there's the fragility factor
-- if something (rock, branch, adjacent racer?) bonks the disc and bends
it, your brakes are screwed, whereas with normal brakes that'd require
bending the whole wheel.

--
Reply to sans two @@, or your reply won't reach me.

Drug smugglers and gun-runners are heroes of American capitalism.
-- Jeffrey Quick

Mike1 wrote:
Given that the tire rim itself functions as essentially an enormous
disc for "regular" brakes, what's the deal here....beyond adding $100
to $150 to the cost of a typical $500 model? Then there's the
fragility factor -- if something (rock, branch, adjacent racer?)
bonks the disc and bends it, your brakes are screwed, whereas with
normal brakes that'd require bending the whole wheel.

Mud doesn't tend to get onto disk brakes as much as it gets onto your rim.
The other big reason for going for disk brakes is modulation - hydraulics
give you more control than cables. Of course, mechanical disk brakes have
the same problems as normal rim brakes when it comes to modulation.

Doki wrote:
Mike1 wrote:

Given that the tire rim itself functions as essentially an enormous
disc for "regular" brakes, what's the deal here....beyond adding $100
to $150 to the cost of a typical $500 model? Then there's the
fragility factor -- if something (rock, branch, adjacent racer?)
bonks the disc and bends it, your brakes are screwed, whereas with
normal brakes that'd require bending the whole wheel.


Mud doesn't tend to get onto disk brakes as much as it gets onto your rim.
The other big reason for going for disk brakes is modulation - hydraulics
give you more control than cables. Of course, mechanical disk brakes have
the same problems as normal rim brakes when it comes to modulation.



you can have hydraulic rim brakes too. What does "modulation" mean in
this context?

Mike1 wrote in message ...
Given that the tire rim itself functions as essentially an enormous disc
for "regular" brakes, what's the deal here....beyond adding $100 to $150
to the cost of a typical $500 model? Then there's the fragility factor
-- if something (rock, branch, adjacent racer?) bonks the disc and bends
it, your brakes are screwed, whereas with normal brakes that'd require
bending the whole wheel.



I think the answer is partly that consumers want things like that and
partly that manufacturers have to distinguish themselves one way or
another. If more people actually used bicycles for utilitarian
purposes like commuting, a lot of this gizmo-mania would fall to the
side.

I have never used a disc brake myself, but from what I understand they
are good for downhill mountain bike terrain where there may be a lot
of mud or extreme heat build-up from heavy braking.

Mike1 Wrote:
Given that the tire rim itself functions as essentially an enormous
disc
for "regular" brakes, what's the deal here....beyond adding $100 to
$150
to the cost of a typical $500 model? Then there's the fragility factor
-- if something (rock, branch, adjacent racer?) bonks the disc and
bends
it, your brakes are screwed, whereas with normal brakes that'd require
bending the whole wheel.

--
Reply to sans two @@, or your reply won't reach
me.

Drug smugglers and gun-runners are heroes of American capitalism.
-- Jeffrey Quick

Disc brakes are far less prone to damage than rim brakes. Disc brakes
work with any sized rim, tire or wheel, it just has to have the correct
disc. Break a spoke and no drag with disc, just a wobble in the wheel.

On monster descents, there is no fear of overheating the rim and having
a blowout.

Wheel changes are simplified, just don't hit the lever while the wheel
is off!

Rims do not wear in mud and discs are cheaper and easier to replace.


--
Weisse Luft

Mike1 wrote in message ...
Given that the tire rim itself functions as essentially an enormous disc
for "regular" brakes, what's the deal here....beyond adding $100 to $150
to the cost of a typical $500 model? Then there's the fragility factor
-- if something (rock, branch, adjacent racer?) bonks the disc and bends
it, your brakes are screwed, whereas with normal brakes that'd require
bending the whole wheel.

All i can say is search this groop for disc brakes & read about all
the problems people have with them.

On Mon, 02 Aug 2004 03:04:51 -0500, Mike1
wrote:


Given that the tire rim itself functions as essentially an enormous disc
for "regular" brakes, what's the deal here....beyond adding $100 to $150
to the cost of a typical $500 model? Then there's the fragility factor
-- if something (rock, branch, adjacent racer?) bonks the disc and bends
it, your brakes are screwed, whereas with normal brakes that'd require
bending the whole wheel.

Not to be flippant, this has been debated to death in this group.

Disc brakes can work more reliably in wet and/or muddy conditions.
(Note that I did not say that they always do; that is not true.)

Bikes equipped with disc brakes are largely immune to the braking
problems that result when a spoke breaks or a wheel gets bent on bike
equipped with rim brakes.

The disc, being smaller and farther off the ground, is often less
likely than the wheel to get damaged in a spill. Disc damage is rare;
wheel tacos are more common. (The fact that wheels are more common
than disc brakes may render this statistic misleading, but for the
moment the assertion seems supported by experience.)

Discs do not heat the rim during long descents.

All of that said, for applications where rim brakes work well, there
is probably no advantage in disc brakes. Like anything else, though,
there are people who will buy them just because disc brakes are
perceived as "the best", whether that is true in a given instance or
not.

Some disc brake adherents state that they prefer the feel of the disc
brakes in action, but as this is a subjective issue, it is probably
not relevant to a generalized discussion. The same assertion is also
made by some rim brake adherents, in point of fact.

There is also a potentially negative technical issue involved with
disc brakes; the common designs can increase the likelihood of the
front wheel being ejected from the fork on hard braking under certain
conditions. There have apparently not been enough such incidents to
cause the US CPSC to issue any recalls or advisories about them.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

On Mon, 2 Aug 2004 12:30:00 +0100, "Doki"
wrote:

Mike1 wrote:
Given that the tire rim itself functions as essentially an enormous
disc for "regular" brakes, what's the deal here....beyond adding $100
to $150 to the cost of a typical $500 model? Then there's the
fragility factor -- if something (rock, branch, adjacent racer?)
bonks the disc and bends it, your brakes are screwed, whereas with
normal brakes that'd require bending the whole wheel.

Mud doesn't tend to get onto disk brakes as much as it gets onto your rim.
The other big reason for going for disk brakes is modulation - hydraulics
give you more control than cables. Of course, mechanical disk brakes have
the same problems as normal rim brakes when it comes to modulation.

This is unit-comparison-dependent. I have a pair of bikes which
demonstrate that a cable-operated disc can be much easier to modulate
than a cable-operated rim brake, at least for the two designs
involved. It is a mistake to apply blanket generalities to this
subject in any area; there are good, bad and indifferent brake units
in all types.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

Mike1 wrote in message ...
Given that the tire rim itself functions as essentially an enormous disc
for "regular" brakes, what's the deal here....beyond adding $100 to $150
to the cost of a typical $500 model? Then there's the fragility factor
-- if something (rock, branch, adjacent racer?) bonks the disc and bends
it, your brakes are screwed, whereas with normal brakes that'd require
bending the whole wheel.

A gimic? Yes and no.

They do have thier place. They are great when you need to stop a lot
of weight on long downhill grades, both off and on road. They are
great in mud, rain, or snow. Ever try to stop with rim brakes in the
snow? I ate the dark anodizing of a pair of road rims on a rainny
century ride one time. They are allso great for special wheel sizes
and other unique applications.

Since I live in a warm dry climate, I can get away with v-brakes . I
do not have to deal with the disc brake down side, which is weight and
cost. Good v-brakes provide all of the stopping power I need right
now. And set up right, they have great modulation.

Yes discs can be a gimic as well. Companies need to sell new bikes
to survive. everyone wants what the pros have. You have to have the
latest and the greatest. Have you seen any new bikes for the past few
years with cantalever brakes? V-brakes will go the same way shortly,
eveen thoough they are perfect for what most people use thier bikes
for. In a few years you will even see disc brakes as standard
equipment on the 45lb dual suspension bikes at Walmart. Except they
will now be 50lb dual suspension bikes with disc brakes that don't
stop, and suspension that still doesn't work....

Rocketman 58,
....Still remembers the days when brakes did not stop the bike, they
just slowed you down.

In article ,
(rocketman58) wrote:

Mike1 wrote in message
...
Given that the tire rim itself functions as essentially an enormous disc
for "regular" brakes, what's the deal here....beyond adding $100 to $150
to the cost of a typical $500 model? Then there's the fragility factor
-- if something (rock, branch, adjacent racer?) bonks the disc and bends
it, your brakes are screwed, whereas with normal brakes that'd require
bending the whole wheel.

A gimic? Yes and no.

They do have thier place. They are great when you need to stop a lot
of weight on long downhill grades, both off and on road. They are
great in mud, rain, or snow. Ever try to stop with rim brakes in the
snow?


Well, no. (But the whole point of me biking many hours a day is to get
buff and tan so that winter comes to Minnesota this year, I won't cook
red like a lobster when I haul my pasty white ass onto a tropical beach
someplace far away from all that! :-P )

Otherwise, I make it a habit to always rapid-pump-squeeze when I'm
braking, so it'll be instinctive when I have to panic-stop in a
situation where I can't afford locking-up.

It occurs to me, just now, that if I took a razor-blade to the insides
of the rubber pads, I could "sipe" them for a lot more gripping
potential. -- Has anybody here ever done that, and if so, what sort of
pattern did you find works best?

--
Reply to sans two @@, or your reply won't reach me.

Drug smugglers and gun-runners are heroes of American capitalism.
-- Jeffrey Quick