Tektro Yoke, what is the Philips Screw for?

I got one of these Tektro yokes http://oi64.tinypic.com/15p3aqb.jpg
for my cantilever brakes.

These yokes are designed to avoid the problem of a broken straddle cable
causing a crash, and they are also wider so you get more travel of the
pads with less cable pull.

There are two Allen screws which secure the straddle cable in the yoke,
and the straddle cable also can't jump out.

But there is a third screw, a Philips screw, that you can kind of see in
the picture.

What is this Philips scre for? You can't really even put it in very far,
and the Allen screw on the other side is already holding the cable in.

On 14/12/2015 18:59, sms wrote:
I got one of these Tektro yokes http://oi64.tinypic.com/15p3aqb.jpg
for my cantilever brakes.

These yokes are designed to avoid the problem of a broken straddle cable
causing a crash, and they are also wider so you get more travel of the
pads with less cable pull.

A broken straddle cable isn't the thing which causes a crash, it's a
broken main cable. And that yoke doesn't seem to address that.

(broken straddle just means no brakes).

There are two Allen screws which secure the straddle cable in the yoke,
and the straddle cable also can't jump out.

But there is a third screw, a Philips screw, that you can kind of see in
the picture.

What is this Philips scre for? You can't really even put it in very far,
and the Allen screw on the other side is already holding the cable in.

Anything to do with tidying away the tail of the main cable?

On Monday, December 14, 2015 at 10:59:18 AM UTC-8, sms wrote:
I got one of these Tektro yokes http://oi64.tinypic.com/15p3aqb.jpg
for my cantilever brakes.

These yokes are designed to avoid the problem of a broken straddle cable
causing a crash, and they are also wider so you get more travel of the
pads with less cable pull.

There are two Allen screws which secure the straddle cable in the yoke,
and the straddle cable also can't jump out.

But there is a third screw, a Philips screw, that you can kind of see in
the picture.

What is this Philips scre for? You can't really even put it in very far,
and the Allen screw on the other side is already holding the cable in.

It appears that's there to lock the cross cable in one place after you have it centered. Under normal set-ups you probably wouldn't need it.

On Monday, December 14, 2015 at 1:46:14 PM UTC-8, Clive George wrote:
On 14/12/2015 18:59, sms wrote:
I got one of these Tektro yokes http://oi64.tinypic.com/15p3aqb.jpg
for my cantilever brakes.

These yokes are designed to avoid the problem of a broken straddle cable
causing a crash, and they are also wider so you get more travel of the
pads with less cable pull.

A broken straddle cable isn't the thing which causes a crash, it's a
broken main cable. And that yoke doesn't seem to address that.

(broken straddle just means no brakes).

There are two Allen screws which secure the straddle cable in the yoke,
and the straddle cable also can't jump out.

But there is a third screw, a Philips screw, that you can kind of see in
the picture.

What is this Philips scre for? You can't really even put it in very far,
and the Allen screw on the other side is already holding the cable in.

Anything to do with tidying away the tail of the main cable?

Yabbut the yoke is not going to get caught in the knobs, being too big to fit up against them squarely, right? It's going to get bounced away by them

On Monday, December 14, 2015 at 4:54:50 PM UTC-5, Doug Landau wrote:
On Monday, December 14, 2015 at 1:46:14 PM UTC-8, Clive George wrote:
On 14/12/2015 18:59, sms wrote:
I got one of these Tektro yokes http://oi64.tinypic.com/15p3aqb.jpg
for my cantilever brakes.

These yokes are designed to avoid the problem of a broken straddle cable
causing a crash, and they are also wider so you get more travel of the
pads with less cable pull.

A broken straddle cable isn't the thing which causes a crash, it's a
broken main cable. And that yoke doesn't seem to address that.

(broken straddle just means no brakes).

There are two Allen screws which secure the straddle cable in the yoke,
and the straddle cable also can't jump out.

But there is a third screw, a Philips screw, that you can kind of see in
the picture.

What is this Philips scre for? You can't really even put it in very far,
and the Allen screw on the other side is already holding the cable in..

Anything to do with tidying away the tail of the main cable?

Yabbut the yoke is not going to get caught in the knobs, being too big to fit up against them squarely, right? It's going to get bounced away by them

Would probably get caught and if not then the straddle wire would most likely get caught by the knobs on the tire edge. You want the wire setup that has the brake cable that runs from the brake lever and then through a button to one of the cantilever arms. A short cable runs from the button to the other arm. With that setup a broken brake cable results in the arms pivoting away from the rim and there's no cross-over cable to drop down and snag on the tire.

Cheers

On 12/14/2015 3:54 PM, Doug Landau wrote:
On Monday, December 14, 2015 at 1:46:14 PM UTC-8, Clive George wrote:
On 14/12/2015 18:59, sms wrote:
I got one of these Tektro yokes http://oi64.tinypic.com/15p3aqb.jpg
for my cantilever brakes.

These yokes are designed to avoid the problem of a broken straddle cable
causing a crash, and they are also wider so you get more travel of the
pads with less cable pull.

A broken straddle cable isn't the thing which causes a crash, it's a
broken main cable. And that yoke doesn't seem to address that.

(broken straddle just means no brakes).

There are two Allen screws which secure the straddle cable in the yoke,
and the straddle cable also can't jump out.

But there is a third screw, a Philips screw, that you can kind of see in
the picture.

What is this Philips scre for? You can't really even put it in very far,
and the Allen screw on the other side is already holding the cable in.

Anything to do with tidying away the tail of the main cable?

Yabbut the yoke is not going to get caught in the knobs, being too big to fit up against them squarely, right? It's going to get bounced away by them


It won't.
In the unlikely event of a main cable failure, the
transverse wire, with or without the aluminum cable hanger,
will jam on the tire and lock the wheel. Tread is
irrelevant. A smooth road tire will lock equally fast and
when I say fast I mean virtually instantaneously, faster
than human reaction time.

Again, this is not a common failure but a mudguard, or
anything really, between carrier and tire is prudent.

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

On 12/14/2015 4:16 PM, Sir Ridesalot wrote:
On Monday, December 14, 2015 at 4:54:50 PM UTC-5, Doug Landau wrote:
On Monday, December 14, 2015 at 1:46:14 PM UTC-8, Clive George wrote:
On 14/12/2015 18:59, sms wrote:
I got one of these Tektro yokes http://oi64.tinypic.com/15p3aqb.jpg
for my cantilever brakes.

These yokes are designed to avoid the problem of a broken straddle cable
causing a crash, and they are also wider so you get more travel of the
pads with less cable pull.

A broken straddle cable isn't the thing which causes a crash, it's a
broken main cable. And that yoke doesn't seem to address that.

(broken straddle just means no brakes).

There are two Allen screws which secure the straddle cable in the yoke,
and the straddle cable also can't jump out.

But there is a third screw, a Philips screw, that you can kind of see in
the picture.

What is this Philips scre for? You can't really even put it in very far,
and the Allen screw on the other side is already holding the cable in.

Anything to do with tidying away the tail of the main cable?

Yabbut the yoke is not going to get caught in the knobs, being too big to fit up against them squarely, right? It's going to get bounced away by them

Would probably get caught and if not then the straddle wire would most likely get caught by the knobs on the tire edge. You want the wire setup that has the brake cable that runs from the brake lever and then through a button to one of the cantilever arms. A short cable runs from the button to the other arm. With that setup a broken brake cable results in the arms pivoting away from the rim and there's no cross-over cable to drop down and snag on the tire.

Cheers


Older cantilever designs unwind to catch the arm(s) on a
spoke when either wire, linked by either method, fails.

That usually rips out a spoke or two and/or the cantilever
boss from the frame/fork in a less dramatic and less
injurious way than a transverse stuck on a tire.

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

friction drag ?

On 12/14/2015 1:54 PM, Doug Landau wrote:

Yabbut the yoke is not going to get caught in the knobs, being too big to fit up against them squarely, right? It's going to get bounced away by them

Without the main wire in place. the yoke doesn't fall down onto the
tire. The straddle cable is stiff enough that it comes down a little as
the springs in the cantilever pull the arms outward. The yoke, with its
Allen screws tightened, gives the straddle wire more rigidity.

You can see a photo of the straddle wire and yoke, with the brake cable
disconnected, at http://oi65.tinypic.com/ioi6j4.jpg. It stays way
above the tire.

With the cheap yokes, the yoke would fall off if the brake cable broke,
and the straddle cable could come out of the right cantilever arm if it
were long enough that there was no spring tension on it anymore.

Part of the advantage of the wider yoke may be that you can have a
shorter straddle cable that's less likely to fall onto the tire.

On 12/14/2015 2:48 PM, AMuzi wrote:

It won't.
In the unlikely event of a main cable failure, the transverse wire, with
or without the aluminum cable hanger, will jam on the tire and lock the
wheel. Tread is irrelevant. A smooth road tire will lock equally fast
and when I say fast I mean virtually instantaneously, faster than human
reaction time.

I disconnected the main cable to see what would happen, and the straddle
cable does NOT fall onto the tire using the Tektro Yoke with the two
Allen set screws. http://oi65.tinypic.com/ioi6j4.jpg.

I did not try this with the cheap yoke so I don't know what would
happen, other than the yoke and whatever was left of the main cable
would fall off.