Drum-Brake Reliable for Long, Steep Descents?

Quoting myself in another thread:

I'm looking around now at some upmarket bikes for when I grow up. I
will be needing a comfort or utility style bike that can be ridden in a
skirt, carry lots of shopping, and tackle very steep hills (i.e. it
should have a fairy gear and rock-hard brakes).

The bike by Giant that I was looking at over the weekend had a V-brake
on the front wheel and a drum-brake on the back wheel. The salesman told
me this was for greater reliability in rainy weather. However, I checked
up what John Forrester had to say about this in EFFECTIVE CYCLING.
Although I find his prose really hard to understand, I dimly intuited
that he thinks any kind of brake on the hub, including a drum brake,
will fail over more than 750 yard descents because it cannot evacuate
heat sufficiently. I gather he recommends side-pull rim-brakes for this
kind of application. Also he is strongly against unequal configurations
on the front and back wheels.

My descent goes on for almost 1.5 km and is _seriously_ steep. So much
so that I have not been able to trust the V-brakes of my
cheap-and-cheerful supermarket bike - I walk the bike over this passage
of the trip, both going uphill (because the lowest gear is no low
enough) and downhill because I cannot trust those flimsy brakes with my
considerable poundage (I weigh over 200 lb alas). So this section alone
takes up 35% of my travel time although it is only 15% of my distance.

Does this group have opinions on the subject of brakes on steep
descents? Is the reliability of the brakes an important factor in the
overall price of a bike? I mean is the cheapness of my current bike (140
Euros, as opposed to 800 Euros for the Giant) likely to correlate with
flimsy brakes, or is the price of reliable brakes fairly constant over
all price ranges? And should I be avoiding drum brakes like the plague?

Many thanks,

Elisa francesca Roselli
Ile de France

check into bikes with disc brakes front and rear. They are pretty common
nowadays. Then you won't have to walk down the hill and you won't have to
worry about overheating your brakes/rims.
-----------------
Alex __O
_-\,_
(_)/ (_)

"Elisa Francesca Roselli"
wrote in message ...
Quoting myself in another thread:

I'm looking around now at some upmarket bikes for when I grow up. I
will be needing a comfort or utility style bike that can be ridden in a
skirt, carry lots of shopping, and tackle very steep hills (i.e. it
should have a fairy gear and rock-hard brakes).

The bike by Giant that I was looking at over the weekend had a V-brake
on the front wheel and a drum-brake on the back wheel. The salesman told
me this was for greater reliability in rainy weather.

Possibly better water protection, but also possibly marketing speak.

However, I checked
up what John Forrester had to say about this in EFFECTIVE CYCLING.
Although I find his prose really hard to understand, I dimly intuited
that he thinks any kind of brake on the hub, including a drum brake,
will fail over more than 750 yard descents because it cannot evacuate
heat sufficiently.

Possibly.

I gather he recommends side-pull rim-brakes for this
kind of application. Also he is strongly against unequal configurations
on the front and back wheels.

Not necessarily bad. After all, you use the front and back completely
different. It's just a matter of getting used to the differences.

My descent goes on for almost 1.5 km and is _seriously_ steep. So much
so that I have not been able to trust the V-brakes of my
cheap-and-cheerful supermarket bike - I walk the bike over this passage
of the trip, both going uphill (because the lowest gear is no low
enough) and downhill because I cannot trust those flimsy brakes with my
considerable poundage (I weigh over 200 lb alas). So this section alone
takes up 35% of my travel time although it is only 15% of my distance.

Please tell us your rims are not chrome plated steel, but instead they are
made of an alloy (not a polished surface).

Does this group have opinions on the subject of brakes on steep
descents? Is the reliability of the brakes an important factor in the
overall price of a bike?

Yes, most assuredly. Inexpensive brakes (drum, V, canti, disc) quite often
are built from not too great materials. And have a lot of flex. And poor
quality pads. Squeeze all you want, and you'll never achieve full braking.

I mean is the cheapness of my current bike (140
Euros, as opposed to 800 Euros for the Giant) likely to correlate with
flimsy brakes,

You don't have to spend 800, but 140 may be a bit low.

or is the price of reliable brakes fairly constant over
all price ranges?

No. Brake levers, arms, and pads all come into play.

And should I be avoiding drum brakes like the plague?

Not necessarily. Especially drum on the rear, because you do not use the
rear as hard as the front. You DO use the front brake more, don't you?

Pete

Elisa Francesca Roselli asked:
Although I find his prose really hard to understand, I dimly intuited
that he thinks any kind of brake on the hub, including a drum brake,
will fail over more than 750 yard descents because it cannot evacuate
heat sufficiently. I gather he recommends side-pull rim-brakes for this
kind of application. Also he is strongly against unequal configurations
on the front and back wheels.
When he implies that any brake on the hub is dangerous for large
descents, does he mean only brakes in the hub (ie drum/drag brakes),
or disc brakes too? As far as heat dissipation goes, I believe a disc
brake (one which grabs a steel disc that is bolted to the hub),
especially one with an 8" rotor diameter, will work much better than a
rim brake. Additionally, these brakes "fade" less than rim brakes,
and don't affet the tire at all. On a really long/steep descent with
rim brakes, it's possible to blow off tires due to the extreme heat
generated from braking.

I cannot trust those flimsy brakes with my
considerable poundage (I weigh over 200 lb alas). So this section alone
takes up 35% of my travel time although it is only 15% of my distance.
Chances are that your brakes are fine - even very cheap V-Brakes (aka
linear pull brakes) work considerably well, given that they are
adjusted properly (that they are tight enough so your lever doesn't
bottom out, and that the pads come in full contact with the rims.)

I mean is the cheapness of my current bike (140
Euros, as opposed to 800 Euros for the Giant) likely to correlate with
flimsy brakes, or is the price of reliable brakes fairly constant over
all price ranges? And should I be avoiding drum brakes like the plague?
Don't think you need to avoid drum brakes like the plague. Rim brakes
should be fine for the situations you describe - especially if they're
V-brakes. Even if they're the older "cantilever" style, as long as
they're adjusted properly, they will stop you just fine. If you don't
feel comfortable with rim brakes, consider disc brakes (especially
look at the Avid mechanical model). They have a better "feel" to
them, though I doubt they're necessary. For more info, check out
http://sheldonbrown.com/brakes/index.html

Bonne chance!
Matt

Elisa Francesca wrote:
Quoting myself in another thread:
I'm looking around now at some upmarket bikes for when I grow up. I
will be needing a comfort or utility style bike that can be ridden in a
skirt, carry lots of shopping, and tackle very steep hills (i.e. it
should have a fairy gear and rock-hard brakes).
The bike by Giant that I was looking at over the weekend had a V-brake
on the front wheel and a drum-brake on the back wheel. The salesman told
me this was for greater reliability in rainy weather. However, I checked
up what John Forrester had to say about this in EFFECTIVE CYCLING.
Although I find his prose really hard to understand, I dimly intuited
that he thinks any kind of brake on the hub, including a drum brake,
will fail over more than 750 yard descents because it cannot evacuate
heat sufficiently. I gather he recommends side-pull rim-brakes for this
kind of application. Also he is strongly against unequal configurations
on the front and back wheels.
My descent goes on for almost 1.5 km and is _seriously_ steep. So much
so that I have not been able to trust the V-brakes of my
cheap-and-cheerful supermarket bike - I walk the bike over this passage
of the trip, both going uphill (because the lowest gear is no low
enough) and downhill because I cannot trust those flimsy brakes with my
considerable poundage (I weigh over 200 lb alas). So this section alone
takes up 35% of my travel time although it is only 15% of my distance.
Does this group have opinions on the subject of brakes on steep
descents? Is the reliability of the brakes an important factor in the
overall price of a bike? I mean is the cheapness of my current bike (140
Euros, as opposed to 800 Euros for the Giant) likely to correlate with
flimsy brakes, or is the price of reliable brakes fairly constant over
all price ranges? And should I be avoiding drum brakes like the plague?
Many thanks,
Elisa francesca Roselli Ile de France

My cruiser has drum brakes on it and they are NOT meant to provide
either great or constant braking. They are good brakes for mellow riding
or well, cruisers and commuters that are not working on fitness or
interval times basically. They work fine in the rain, but not much
better than a decent set of v-brakes. The only "cool" thing about them
is they provide for clean lines on your rig and are not the norm. You
can buy great v-brakes (shimano XT) for not much more than $100 (US) if
you shop around on the net. Not that I live in Europe, but from reading
some posts around and watching what's available, you should be able to
get something with good v-brakes for 800 euro and be every bit capable
of the hill you mention. Good luck and keep shopping. It sounds like the
shop you went to wasn't working very hard for you and that IS their job.
Take care.

K.




--
Don't give up, don't ever give up.

--------------------------
Posted via cyclingforums.com
http://www.cyclingforums.com

Pete wrote:

Not necessarily bad. After all, you use the front and back completely
different. It's just a matter of getting used to the differences.

I'm not sure I do use them so differently? When I want to stop, I slam them
both on.

Please tell us your rims are not chrome plated steel, but instead they are
made of an alloy (not a polished surface).

I have no idea what they are. They are a medium-shiny grey metal. In wet
weather the brakes sing like Wagnerian Valkyries.

. Inexpensive brakes (drum, V, canti, disc) quite often
are built from not too great materials. And have a lot of flex. And poor
quality pads. Squeeze all you want, and you'll never achieve full braking.

I've had the brakes adjusted once already, and have tightened the cable once,
but I'm never really happy with them. I've had the bike for about a year now.
I don't know how many kms it's supposed to deliver before I have to get the
pads changed or whatever. There are 314 kms on the computer but I only
installed that about half-way through and it has been reinitialized at least
once so that's an "at least".

You don't have to spend 800, but 140 may be a bit low.

Well, 800 was the price of the whole bike, which was a nice one with all sorts
of attractive features. This was the brake configuration it came with. Only it
was thinking of itself as a comfort city bike and not one whose daily vocation
just happens to include a monster hill. My problem is that my needs intersect
two different and sometimes contradictory idioms of bike. On the one hand, I'm
a sedate middle-aged fat lady who will be using it to cart groceries, on the
other the daily trip to work could soon involve stints fit for a BMX.


Especially drum on the rear, because you do not use the
rear as hard as the front. You DO use the front brake more, don't you?

No, I think I use the back brake more - at least it's the one that wears out
faster. When braking, I tend to pull on both brakes about equally, but I don't
like the pitchover feeling on the front brake. Also, the front brake is
actioned by the left-hand lever, and the back brake by the right-hand lever.
This means that the back-brake is the one I use whenever I am walking the
bike, since I prefer to walk it on my right side, with my right hand on the
handlebars and my left hand often under the seat. In Contintental Europe that
also is the configuration for walking on the left side of the road, contrary
to oncoming traffic. So when I walk it downhill as I described, it's on the
back brake almost all the time.

Elisa Francesca Roselli
Ile de France

wrote in part:

I checked
up what John Forrester had to say about this in EFFECTIVE CYCLING.
Although I find his prose really hard to understand, I dimly intuited
that he thinks any kind of brake on the hub, including a drum brake,
will fail over more than 750 yard descents because it cannot evacuate
heat sufficiently. I gather he recommends side-pull rim-brakes for this
kind of application. Also he is strongly against unequal configurations
on the front and back wheels.

My descent goes on for almost 1.5 km and is _seriously_ steep.

I don't know if they are still operating but for several years there was a
bicycle tour company in Hawaii that offered a "Bike The Crater" package at
Mount Haleakala. (Forgive me if I've butchered that name spelling.) As I
recall, that ride is/was a 20+ mile descent with more than a few "seriously
steep" sections. All the bikes they used were equipped with front disc/rear
drum brake combinations.

Regards,
Bob Hunt

Elisa Roselli writes:

I checked up what John Forester had to say about this in DEFECTIVE
CYCLING. Although I find his prose really hard to understand, I
dimly intuited that he thinks any kind of brake on the hub,
including a drum brake, will fail over more than 750 yard descents
because it cannot evacuate heat sufficiently. I gather he recommends
side-pull rim-brakes for this kind of application. Also he is
strongly against unequal configurations on the front and back
wheels.

That is a dangerous proposition if you intend to descend mountain
roads that require much braking. Blowing tires off rims is a common
ill of tandems. It even occurs on singles if initial inflation
pressure is high. By all means get a hub brake for the rear wheel.
Your bicycle shop, if they tour on tandems, will know which is best.

My descent goes on for almost 1.5 km and is _seriously_ steep.

I don't know if they are still operating but for several years there
was a bicycle tour company in Hawaii that offered a "Bike The
Crater" package at Mount Haleakala. I recall, that ride is/was a
20+ mile descent with more than a few "seriously steep" sections.
All the bikes they used were equipped with front disc/rear drum
brake combinations.

That is because even a poor hub brake cannot cause a tire blow-off.
There is method to that proposal and it should be heeded. I have been
involved in tandem tire blow-off litigation and they involved
injuries. I have blown a tire on my single as have a few of my riding
companions, let alone the ones the bicycle shop can tell about.

Jobst Brandt

I'll throw in my .02 eurocents, not worth much more than that... :-)

Elisa Francesca Roselli wrote:

: on the front wheel and a drum-brake on the back wheel. The salesman told
: me this was for greater reliability in rainy weather. However, I checked
: up what John Forrester had to say about this in EFFECTIVE CYCLING.

Some research doesn't hurt, hehe :-)

: Although I find his prose really hard to understand, I dimly intuited
: that he thinks any kind of brake on the hub, including a drum brake,
: will fail over more than 750 yard descents because it cannot evacuate
: heat sufficiently. I gather he recommends side-pull rim-brakes for this
: kind of application. Also he is strongly against unequal configurations
: on the front and back wheels.

My understanding is that any conventional (rim, disc, drum, etc)
braking system has an issue with heat on long, steep, fast
descents. It's not really the type of brake but whether it was
designed for demanding descending applications. Disc brakes are
not immune, we had a thread about this in rec.bicycles.tech in the
last few months. As comes to disc brakes, a 200 mm rotor vs a 160
mm one makes a huge difference. (For us mathematical people, it
appears as if the area of the rotor would almost double.)

You could approach this problem like any engineering one. How
steep is the descent and how fast do you go? The difference
between 30 km/h and 70 km/h can be quite significant - although at
70 km/h you'd get a huge braking effect from aerodynamic drag.
Consider the most extreme descending scenario you intend to ever
do. This will establish how much potential energy is converted
into kinetic energy and how much your braking system needs to
convert to thermal energy.

Next you obtain the specs for various braking systems, eg.
different kinds of conventional and heavy-duty brakes, and compare
that to your requirements. Well, exact figures are hardly
available so you just do an educated guesstimate and then add a
huge margin just to be safe :-)

One cheap system could be a duplicate rear brake, eg. a rim brake
and a drum brake on the rear wheel. You could control the rim
brake with a friction lever, so you'd just put it on in the
beginning of the descent, and it would drag just a bit for the
complete descent, and in the end you'd take it off.

: My descent goes on for almost 1.5 km and is _seriously_ steep. So much
: so that I have not been able to trust the V-brakes of my
: cheap-and-cheerful supermarket bike - I walk the bike over this passage
: of the trip, both going uphill (because the lowest gear is no low
: enough) and downhill because I cannot trust those flimsy brakes with my
: considerable poundage (I weigh over 200 lb alas). So this section alone
: takes up 35% of my travel time although it is only 15% of my distance.

Aha, body weight is a factor as well. (Consider what makes
tandems different...)

You probably don't need to walk downhill. If you descend very
slowly and use both brakes, there is no overheating problem. Also,
consider that you have two independent braking systems. AFAIK if
you keep both in good shape, the simultaneous failure of both
should be extremely rare. Even if both failed at once, some
emergency measures could be taken... though I think any really
reasonable cyclist would just make sure that both of them NEVER
fail at the same time. If one of them ever failed, I'd *definitely*
walk the bike down any real hill.

Well that's my .02 on somebody else's descent :-)

--
Risto Varanka | http://www.helsinki.fi/~rvaranka/hpv/hpv.html
varis at no spam please iki fi

Have you checked out any tandems? Drum brakes aka "drag brakes" are a
common option. Set the drum for a chosen amount of braking and forget it on
the descent. Use the hand brakes as usual while descending.
bb

wrote in message
...
I'll throw in my .02 eurocents, not worth much more than that... :-)
huge margin just to be safe :-)

One cheap system could be a duplicate rear brake, eg. a rim brake
and a drum brake on the rear wheel. You could control the rim
brake with a friction lever, so you'd just put it on in the
beginning of the descent, and it would drag just a bit for the
complete descent, and in the end you'd take it off.
--
Risto Varanka | http://www.helsinki.fi/~rvaranka/hpv/hpv.html
varis at no spam please iki fi