Avids Force Vector Alignment (FVA)

"Cychlo-path" <[email hidden]> wrote in message
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Quoted message said:

Anyone know how this is achieved (i.e. what's the physical mechanism?). Is
it like the self-energising canti of the past in which the c arms are
dragged rim-wards?

I thought it was just a marketing term which did nothing.

Greg

"G.T." <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

"Cychlo-path" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Anyone know how this is achieved (i.e. what's the physical mechanism?).

Is

Quoted message said:

Quoted message said:

it like the self-energising canti of the past in which the c arms are
dragged rim-wards?

I thought it was just a marketing term which did nothing.

Greg

Oh, well i wouldn't be surprised I suppose. But they claim reduced flex; in
comparison to what?

"Cychlo-path" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

"G.T." <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

"Cychlo-path" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Anyone know how this is achieved (i.e. what's the physical mechanism?).

Is

Quoted message said:

Quoted message said:

it like the self-energising canti of the past in which the c arms are
dragged rim-wards?

I thought it was just a marketing term which did nothing.

Greg

Oh, well i wouldn't be surprised I suppose. But they claim reduced flex;
in
comparison to what?

That's what I never figured out so I blew it off as marketing BS.

Greg

Cychlo-path said:

Anyone know how this is achieved (i.e. what's the physical
mechanism?). Is it like the self-energising canti of the past in
which the c arms are dragged rim-wards?

Concave washers was what I always thought it was. I found it remarkably
similar to the special SDCA (Super-Duper Caliper Alignment) feature of
u-brakes where you bend the arms slightly to get the pad square to the rim.
😉

--
Phil

Phil said:

Cychlo-path said:

Anyone know how this is achieved (i.e. what's the physical
mechanism?). Is it like the self-energising canti of the past in
which the c arms are dragged rim-wards?

Concave washers was what I always thought it was. I found it remarkably
similar to the special SDCA (Super-Duper Caliper Alignment) feature of
u-brakes where you bend the arms slightly to get the pad square to the rim.

I've bent them too on occasion. But U-Brakes were uniformly supplied
with mating concave/convex pad spacers. The original U-Brake style
shoes/washers are still very available, cheap.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

On Feb 26, 9:29 pm, "Phil, Non-Squid" <[email hidden]>

Quoted message said:

Cychlo-path said:

Anyone know how this is achieved (i.e. what's the physical
mechanism?). Is it like the self-energising canti of the past in
which the c arms are dragged rim-wards?

Concave washers was what I always thought it was. I found it remarkably
similar to the special SDCA (Super-Duper Caliper Alignment) feature of
u-brakes where you bend the arms slightly to get the pad square to the rim.
😉

I think what Avid means by Force Vector Alignment is
that the brake pad post on Avid's canti and v brakes
is behind the arm, rather than in front of the arm, as
on many other brakes. This means that the pad is
roughly in the same plane as the base of the brake
mounting boss where it attaches to the fork or
seatstays. When the brakes squeeze the rim,
they exert the same force on the boss no matter
where the pad is located, but there is less of a
bending moment on the boss with the Avid style
[which may not be original to them]
because the leverage of the pad on the boss is
shorter. This is why Avid claims "The Force Vector
Alignment[tm] design reduces boss movement" [or splay]

I have no idea if this is really important enough
to require a trademark and three letter acronym.
You might think it would reduce squeal, but Avid
cantis have a reputation for squealing, so there
goes that theory.

Ben

Quoted message said:

On Feb 26, 9:29 pm, "Phil, Non-Squid" <[email hidden]>

Quoted message said:

Cychlo-path said:

Anyone know how this is achieved (i.e. what's the physical
mechanism?). Is it like the self-energising canti of the past in
which the c arms are dragged rim-wards?

Concave washers was what I always thought it was. I found it
remarkably similar to the special SDCA (Super-Duper Caliper
Alignment) feature of u-brakes where you bend the arms slightly to
get the pad square to the rim. 😉

I think what Avid means by Force Vector Alignment is
that the brake pad post on Avid's canti and v brakes
is behind the arm, rather than in front of the arm, as
on many other brakes. This means that the pad is
roughly in the same plane as the base of the brake
mounting boss where it attaches to the fork or
seatstays. When the brakes squeeze the rim,
they exert the same force on the boss no matter
where the pad is located, but there is less of a
bending moment on the boss with the Avid style
[which may not be original to them]
because the leverage of the pad on the boss is
shorter. This is why Avid claims "The Force Vector
Alignment[tm] design reduces boss movement" [or splay]

I have no idea if this is really important enough
to require a trademark and three letter acronym.
You might think it would reduce squeal, but Avid
cantis have a reputation for squealing, so there
goes that theory.

Ben

What models of v-brakes have the brake pad post in front of the caliper arm?
IMLE, I don't think I've ever seen any.
--
Phil

A Muzi said:

Phil said:

Cychlo-path said:

Anyone know how this is achieved (i.e. what's the physical
mechanism?). Is it like the self-energising canti of the past in
which the c arms are dragged rim-wards?

Concave washers was what I always thought it was. I found it
remarkably similar to the special SDCA (Super-Duper Caliper
Alignment) feature of u-brakes where you bend the arms slightly to
get the pad square to the rim.

I've bent them too on occasion. But U-Brakes were uniformly supplied
with mating concave/convex pad spacers. The original U-Brake style
shoes/washers are still very available, cheap.

Whoops. I meant to say "sidepull" like these:

http://beauty.nagog.smasher.net:81/bike/3speedupdate/oldfrontbrake.jpg

or

http://www.jensonusa.com/store/product/BR407G01-Tektro+Bmx+Sidepull+Afs+Black.aspx
--
Phil

On Feb 27, 8:10 pm, "Phil, Non-Squid" <[email hidden]>

Quoted message said:

Quoted message said:

I think what Avid means by Force Vector Alignment is
that the brake pad post on Avid's canti and v brakes
is behind the arm, rather than in front of the arm, as
on many other brakes.

What models of v-brakes have the brake pad post in front of the caliper arm?
IMLE, I don't think I've ever seen any.

I can't think of any, but I was looking at my MTB
with a pair of old high-profile XT cantilevers
when I wrote that, and those do have the post in
front of the arm, as do many other styles of cantis,
but not all.

Ben

in article [email hidden], Phil, Non-Squid at
[email hidden] wrote on 28/2/07 03:10:

Quoted message said:

What models of v-brakes have the brake pad post in front of the caliper arm?
IMLE, I don't think I've ever seen any.

My STX-RC V-brakes have the pad posts going in front. They also take
plain-post cantilever pads.

Ben