Pedersen self energizing brakes.
 

Every day is an adventure for a new bike mechanic. There seems to be n
end to the exotic componentry out there.
I just had a unit come in with the Pedersen cantis. It was easy enoug
to figure out how they work, the only real mystery is, well, why? I a
certainly no engineer,so maybe someone who is can explain the advantag
if there is one. How does moving the pads forward as the brake arm
rotate toward rim contact energize the brake?
Was this just another answer to a question no one asked

--
Dan Burkhar

Pedersen self energizing brakes.
 

On Mon, 6 Jun 2005 13:18:52 +1000, Dan Burkhart
wrote:


Every day is an adventure for a new bike mechanic. There seems to be no
end to the exotic componentry out there.
I just had a unit come in with the Pedersen cantis. It was easy enough
to figure out how they work, the only real mystery is, well, why? I am
certainly no engineer,so maybe someone who is can explain the advantage
if there is one. How does moving the pads forward as the brake arms
rotate toward rim contact energize the brake?
Was this just another answer to a question no one asked?

You answered one of your own questions he

"How does moving the pads forward as the brake arms
rotate toward rim contact energize the brake?"

Look at this statement backwards - the brake arms rotate towards the
rim as they move forwards.

When the rider squeezes the lever, the brake blocks make contact with
the rim. Friction between the rim and the block means that the block
and its attached arm are dragged forward. The forward motion causes
the arms to move inwards somewhat, causing an increase in the force
holding the block againast the rim.

Other manufacturers produced similar designs - the only one I could
remember off the top of my head being Scott. Interestingly, the first
Google hit for "Scott self energizing brake" is a section on John
Forester's site relating to a lawsuit:
http://www.johnforester.com/Articles...ng/sebrake.htm

Hit No. 2 is Sheldon's site:
http://www.sheldonbrown.com/gloss_sa-o.html#self

As to they're being an answer to an unasked question, probably so.
So much "innovation" and "development" in bicycle tech seems to be a
marketing (rather than market) led drive to obsolete current
components in order to keep customers on the purchasing treadmill.

Pedersen self energizing brakes.
 

Dan Burkhart wrote:
Every day is an adventure for a new bike mechanic. There seems to be no
end to the exotic componentry out there.
I just had a unit come in with the Pedersen cantis. It was easy enough
to figure out how they work, the only real mystery is, well, why? I am
certainly no engineer,so maybe someone who is can explain the advantage
if there is one. How does moving the pads forward as the brake arms
rotate toward rim contact energize the brake?
Was this just another answer to a question no one asked?

I have a pair sitting around in the spares box. I never thought they
had any more power than regular brakes when I used them (they came with
a bike).

Anyway, there's a helix in there which applies the brake harder as the
pads are dragged forward by the rim.

Pedersen self energizing brakes.
 

Zog The Undeniable wrote:

I have a pair sitting around in the spares box. I never thought they
had any more power than regular brakes when I used them (they came with
a bike).

Anyway, there's a helix in there which applies the brake harder as the
pads are dragged forward by the rim.

I have a pair made by Sun Tour - they were only for back brakes I think.
I replaced with V brakes which work better, although my old U-Brake on
my Muddy Fox is pretty good too.

Pedersen self energizing brakes.
 

the answer is!!!

http://www.vintagebike.co.uk/Bike%20...rel%201929.htm

and the question is!!!

why does it not work??

Pedersen self energizing brakes.
 

check the Velocette Venom 500!!!

Pedersen self energizing brakes.
 

Zog The Undeniable wrote:

Anyway, there's a helix in there which applies the brake harder as the
pads are dragged forward by the rim.

OK, I understand that is the theory. What I don't grasp is how the
brake can be applied "harder" without a corresponding increase in the
force at the brake lever (through the cable), where the riders grip is
the only thing securing the brake lever.

Is this perhaps just a matter of anatomy where it is easier for the
hand to resist a force statically than it is to dynamically apply the
same force?

Am I missing something somewhere?

DR

Pedersen self energizing brakes.
 

Dirtroadie wrote:
Zog The Undeniable wrote:

Anyway, there's a helix in there which applies the brake harder as the
pads are dragged forward by the rim.

OK, I understand that is the theory. What I don't grasp is how the
brake can be applied "harder" without a corresponding increase in the
force at the brake lever (through the cable), where the riders grip is
the only thing securing the brake lever.

Is this perhaps just a matter of anatomy where it is easier for the
hand to resist a force statically than it is to dynamically apply the
same force?

Am I missing something somewhere?

DR

The rotating force of the wheel pulls the pad forward.. the mechanism
then forces the pads tighter into the rim..

they worked OK when installed correctly.. except on some bikes where
most of the extra force went into forcing the canti pegs outward (the
stays would twist) the GT triple triangle were the worst.
Adding a brake booster would fix the stay flex and then they worked
quite well (assuming they were installed correctly)

Pedersen self energizing brakes.
 

Quoting Zog The Undeniable :
I have a pair sitting around in the spares box. I never thought they
had any more power than regular brakes when I used them (they came with
a bike).

On a normal bike, of course, any decent rear brake will lock the rear
wheel and the SE cantilevers offer no advantage.

However, on a tandem the cable run is much longer and the potential
maximum rear braking is much greater because the centre of gravity is much
further behind the rear wheel but no higher off the ground. That's the
real use of these brakes.
--
David Damerell flcl?
Today is First Gloucesterday, June.

Pedersen self energizing brakes.