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Q: Shimano cantilever straddle cable length?



 
 
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  #1  
Old October 18th 09, 02:41 PM posted to rec.bicycles.tech
somebody[_2_]
external usenet poster
 
Posts: 133
Default Q: Shimano cantilever straddle cable length?

I'm thinking of using some Shimano BR-550's on a road bike with Alex
DM-18 rims. I can pick one of several fixed straddle cables. Which
one?

Is it related to rim width, where we want length that produces a
specific angle based on brake model? Does that mean the geometry
won't be quite right when switching to another rim? I checked the
Sheldon stuff but don't have enough experience to pick the right one.

Thanks!

Adjustment:
http://www.sheldonbrown.com/canti-trad.html#yoke

The brakes:
http://www.sheldonbrown.com/harris/c...ers/index.html
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  #2  
Old October 18th 09, 04:02 PM posted to rec.bicycles.tech
landotter
external usenet poster
 
Posts: 6,312
Default Q: Shimano cantilever straddle cable length?

On Oct 18, 8:41*am, somebody wrote:
I'm thinking of using some Shimano BR-550's on a road bike with Alex
DM-18 rims. *I can pick one of several fixed straddle cables. *Which
one?


Use the one it comes with and work from there. Chances are that a
normal canti with an average sized rim like that will work pretty well
with the average sized linkage included. ;-)


Cheaper and better, IMHO, are the Tektro CR720s on that same page.
They come with an adjustable straddle setup. Stock pads are better
than Shimano. Only reason not to use them would be clearance issues as
they stick out a bit. Set em up so the yoke makes about a 90 degree
angle. See how you like that first, then lengthen or shorten as
desired.


  #3  
Old October 18th 09, 08:31 PM posted to rec.bicycles.tech
AMuzi
external usenet poster
 
Posts: 5,806
Default Q: Shimano cantilever straddle cable length?

somebody wrote:
I'm thinking of using some Shimano BR-550's on a road bike with Alex
DM-18 rims. I can pick one of several fixed straddle cables. Which
one?
Is it related to rim width, where we want length that produces a
specific angle based on brake model? Does that mean the geometry
won't be quite right when switching to another rim? I checked the
Sheldon stuff but don't have enough experience to pick the right one.
Adjustment:
http://www.sheldonbrown.com/canti-trad.html#yoke
The brakes:
http://www.sheldonbrown.com/harris/c...ers/index.html


You want the size which ends with a 90-degree angle as the
pads touch. That varies by brake stud position and rim
width. Some brakes allow lateral pad adjustment which can
help to get that just right with various LinkWire sizes.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971
  #4  
Old October 19th 09, 11:41 PM posted to rec.bicycles.tech
somebody[_2_]
external usenet poster
 
Posts: 133
Default Q: Shimano cantilever straddle cable length?

On Sun, 18 Oct 2009 14:31:30 -0500, AMuzi wrote:

somebody wrote:
I'm thinking of using some Shimano BR-550's on a road bike with Alex
DM-18 rims. I can pick one of several fixed straddle cables. Which
one?
Is it related to rim width, where we want length that produces a
specific angle based on brake model? Does that mean the geometry
won't be quite right when switching to another rim? I checked the
Sheldon stuff but don't have enough experience to pick the right one.
Adjustment:
http://www.sheldonbrown.com/canti-trad.html#yoke
The brakes:
http://www.sheldonbrown.com/harris/c...ers/index.html


You want the size which ends with a 90-degree angle as the
pads touch. That varies by brake stud position and rim
width. Some brakes allow lateral pad adjustment which can
help to get that just right with various LinkWire sizes.


That's it. The brakes came with two different straddle cable sizes;
the previous owner worked at a shop and must have swapped in what
worked on his bike. That means I can try each and check the angle.

How are Shimano straddle/yoke cables measured? Is it base on the
length that sticks out of the middle?

Thanks!
  #5  
Old October 20th 09, 11:51 PM posted to rec.bicycles.tech
jay
external usenet poster
 
Posts: 117
Default Q: Shimano cantilever straddle cable length?

On Oct 19, 3:41*pm, somebody wrote:
On Sun, 18 Oct 2009 14:31:30 -0500, AMuzi wrote:
somebody wrote:
I'm thinking of using some Shimano BR-550's on a road bike with Alex
DM-18 rims. *I can pick one of several fixed straddle cables. *Which
one?
Is it related to rim width, where we want length that produces a
specific angle based on brake model? *Does that mean the geometry
won't be quite right when switching to another rim? *I checked the
Sheldon stuff but don't have enough experience to pick the right one.
Adjustment:
http://www.sheldonbrown.com/canti-trad.html#yoke
The brakes:
http://www.sheldonbrown.com/harris/c...ers/index.html


You want the size which ends with a 90-degree angle as the
pads touch. That varies by brake stud position and rim
width. Some brakes allow lateral pad adjustment which can
help to get that just right with various LinkWire sizes.


That's it. *The brakes came with two different straddle cable sizes;
the previous owner worked at a shop and must *have swapped in what
worked on his bike. *That means I can try each and check the angle.

How are Shimano straddle/yoke cables measured? *Is it base on the
length that sticks out of the middle?

Thanks!


How are Shimano straddle/yoke cables measured? Is it base on the
length that sticks out of the middle?


Thatís good question!
After measuring several straddle links, Iíve come the conclusion that
itís the length of exposed cable from where it exitís the center
device to where it disappears into the lead casting @ the other end.
It isnít the same as the C-C distance, & therefore not usable in trig
calculations. However it isnít necessary to do any trig calculations
to try to get the optimum length.
As Andrew so succinctly pointed out the goal is to get the length such
that the straddle cables make a 90 deg or slightly smaller angle when
the pads hit the rim. Thatís w/ the angle measured @ the point where
the line from the pivot point of the brake arm intersects the cable
attachment, w/ the cable running to the center device as the other
line making the angle.
However, so far so I know itís usually impossible to get a 90 or 90
deg. angle w/ the ďnarrowĒ or ďup rightĒ type of cantilevere arms. The
angle usually ends up more oblique that 90 deg. Therefore the idea is
to get an angle that is as close to 90 deg. While still clearing the
tire, fenders, racks, etc. Itís quite easy to get this 90 deg. or w/
the older style wide cantilevers such as ďPaulísĒ.
The idea of using straddle links in lieu for a single straddle cable
was to keep the straddle cable from getting caught on Mt.B. tire knobs
& tossing the rider over the bars in case of the primary brake cable
severing. I donít think this is much of a problem w/ relatively smooth
road tires, & therefore use a plain straddle cable on road bikes for
the greater ease of optimizing geometry.

The use of non threaded brake pad posts (or smooth posts) allows one
to extend the pads of upright arms further from the brake arm to
improve the angle of the straddle cable to brake arm. Doing this,
however brings on other problems. These are increased chance of brake
squeal, & the difficulty of adjusting smooth arm pads. In my
experience the rotating tabs that set toe-in & all the other pad
adjustments, are made of plastic that has to be torqued very tight.
This torque causes the plastic to deform creating a crease where the
pad post is. This isnít so bad when it is the 1st time the brakes are
set up, but subsequent adjustments make it just about impossible to
keep the pad post from being captured by this crease. There are work
arounds, but are a pain too. I donít remember all the smooth pad posts
Iíve worked on. There may be some that donít have these adjustability
problems.
I would appreciate knowing which, if any, they are.

  #6  
Old October 21st 09, 12:30 AM posted to rec.bicycles.tech
AMuzi
external usenet poster
 
Posts: 5,806
Default Q: Shimano cantilever straddle cable length?

jay wrote:
On Oct 19, 3:41 pm, somebody wrote:
On Sun, 18 Oct 2009 14:31:30 -0500, AMuzi wrote:
somebody wrote:
I'm thinking of using some Shimano BR-550's on a road bike with Alex
DM-18 rims. I can pick one of several fixed straddle cables. Which
one?
Is it related to rim width, where we want length that produces a
specific angle based on brake model? Does that mean the geometry
won't be quite right when switching to another rim? I checked the
Sheldon stuff but don't have enough experience to pick the right one.
Adjustment:
http://www.sheldonbrown.com/canti-trad.html#yoke
The brakes:
http://www.sheldonbrown.com/harris/c...ers/index.html
You want the size which ends with a 90-degree angle as the
pads touch. That varies by brake stud position and rim
width. Some brakes allow lateral pad adjustment which can
help to get that just right with various LinkWire sizes.

That's it. The brakes came with two different straddle cable sizes;
the previous owner worked at a shop and must have swapped in what
worked on his bike. That means I can try each and check the angle.

How are Shimano straddle/yoke cables measured? Is it base on the
length that sticks out of the middle?

Thanks!


How are Shimano straddle/yoke cables measured? Is it base on the
length that sticks out of the middle?


Thatís good question!
After measuring several straddle links, Iíve come the conclusion that
itís the length of exposed cable from where it exitís the center
device to where it disappears into the lead casting @ the other end.
It isnít the same as the C-C distance, & therefore not usable in trig
calculations. However it isnít necessary to do any trig calculations
to try to get the optimum length.
As Andrew so succinctly pointed out the goal is to get the length such
that the straddle cables make a 90 deg or slightly smaller angle when
the pads hit the rim. Thatís w/ the angle measured @ the point where
the line from the pivot point of the brake arm intersects the cable
attachment, w/ the cable running to the center device as the other
line making the angle.
However, so far so I know itís usually impossible to get a 90 or 90
deg. angle w/ the ďnarrowĒ or ďup rightĒ type of cantilevere arms. The
angle usually ends up more oblique that 90 deg. Therefore the idea is
to get an angle that is as close to 90 deg. While still clearing the
tire, fenders, racks, etc. Itís quite easy to get this 90 deg. or w/
the older style wide cantilevers such as ďPaulísĒ.
The idea of using straddle links in lieu for a single straddle cable
was to keep the straddle cable from getting caught on Mt.B. tire knobs
& tossing the rider over the bars in case of the primary brake cable
severing. I donít think this is much of a problem w/ relatively smooth
road tires, & therefore use a plain straddle cable on road bikes for
the greater ease of optimizing geometry.

The use of non threaded brake pad posts (or smooth posts) allows one
to extend the pads of upright arms further from the brake arm to
improve the angle of the straddle cable to brake arm. Doing this,
however brings on other problems. These are increased chance of brake
squeal, & the difficulty of adjusting smooth arm pads. In my
experience the rotating tabs that set toe-in & all the other pad
adjustments, are made of plastic that has to be torqued very tight.
This torque causes the plastic to deform creating a crease where the
pad post is. This isnít so bad when it is the 1st time the brakes are
set up, but subsequent adjustments make it just about impossible to
keep the pad post from being captured by this crease. There are work
arounds, but are a pain too. I donít remember all the smooth pad posts
Iíve worked on. There may be some that donít have these adjustability
problems.
I would appreciate knowing which, if any, they are.



It's not just knobby tires. A transverse will grab any tire
and likely injure (kill?) the rider in the event of a failed
main wire.

It's good practice to ensure there's a mudguard, lamp
bracket or something between transverse and tire on a
non-LinkWire setup. You can argue helmets but not this.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971
  #7  
Old October 21st 09, 01:07 AM posted to rec.bicycles.tech
landotter
external usenet poster
 
Posts: 6,312
Default Q: Shimano cantilever straddle cable length?

On Oct 20, 6:30*pm, AMuzi wrote:
jay wrote:
On Oct 19, 3:41 pm, somebody wrote:
On Sun, 18 Oct 2009 14:31:30 -0500, AMuzi wrote:
somebody wrote:
I'm thinking of using some Shimano BR-550's on a road bike with Alex
DM-18 rims. *I can pick one of several fixed straddle cables. *Which
one?
Is it related to rim width, where we want length that produces a
specific angle based on brake model? *Does that mean the geometry
won't be quite right when switching to another rim? *I checked the
Sheldon stuff but don't have enough experience to pick the right one..
Adjustment:
http://www.sheldonbrown.com/canti-trad.html#yoke
The brakes:
http://www.sheldonbrown.com/harris/c...ers/index.html
You want the size which ends with a 90-degree angle as the
pads touch. That varies by brake stud position and rim
width. Some brakes allow lateral pad adjustment which can
help to get that just right with various LinkWire sizes.
That's it. *The brakes came with two different straddle cable sizes;
the previous owner worked at a shop and must *have swapped in what
worked on his bike. *That means I can try each and check the angle.


How are Shimano straddle/yoke cables measured? *Is it base on the
length that sticks out of the middle?


Thanks!


How are Shimano straddle/yoke cables measured? *Is it base on the
length that sticks out of the middle?


Thatís *good question!
After measuring several straddle links, Iíve come the conclusion that
itís the length of exposed cable from where it exitís the center
device to where it disappears into the lead casting @ the other end.
It isnít the same as the C-C distance, & therefore not usable in trig
calculations. However it isnít necessary to do any trig calculations
to try to get the optimum length.
As Andrew so succinctly pointed out the goal is to get the length such
that the straddle cables make a 90 deg or slightly smaller angle when
the pads hit the rim. Thatís w/ the angle measured @ the point where
the line from the pivot point of the brake arm intersects the cable
attachment, w/ the cable running to the center device as the other
line making the angle.
However, so far so I know itís usually impossible to get a 90 or 90
deg. angle w/ the ďnarrowĒ or ďup rightĒ type of cantilevere arms. The
angle usually ends up more oblique that 90 deg. Therefore the idea is
to *get an angle that is as close to 90 deg. While still clearing the
tire, fenders, racks, etc. Itís quite easy to get this 90 deg. or w/
the older style wide cantilevers such as ďPaulísĒ.
The idea of using straddle links in lieu for a single straddle cable
was to keep the straddle cable from getting caught on Mt.B. tire knobs
& tossing the rider over the bars in case of the primary brake cable
severing. I donít think this is much of a problem w/ relatively smooth
road tires, & therefore use a plain straddle cable on road bikes for
the greater ease of optimizing geometry.


The use of non threaded brake pad posts (or smooth posts) allows one
to extend the pads of upright arms further from the brake arm to
improve the angle of the straddle cable to brake arm. Doing this,
however brings on other problems. These are increased chance of brake
squeal, & the difficulty of adjusting smooth arm pads. In my
experience the rotating tabs that set toe-in & all the other pad
adjustments, are made of plastic that has to be torqued very tight.
This torque causes the plastic to deform creating a crease where the
pad post is. This isnít so bad when it is the 1st *time the brakes are
set up, but subsequent adjustments make it just about impossible to
keep the pad post from being captured by this crease. There are work
arounds, but are a pain too. I donít remember all the smooth pad posts
Iíve worked on. There may be some that donít have these adjustability
problems.
I would appreciate knowing which, if any, they are.


It's not just knobby tires. A transverse will grab any tire
and likely injure (kill?) the rider in the event of a failed
main wire.

It's good practice to ensure there's a mudguard, lamp
bracket or something between transverse and tire on a
non-LinkWire setup. You can argue helmets but not this.

Agreed--and link wires don't make you look like a Fred, either!

  #8  
Old October 21st 09, 01:32 AM posted to rec.bicycles.tech
pm
external usenet poster
 
Posts: 344
Default Q: Shimano cantilever straddle cable length?

On Oct 20, 5:07*pm, landotter wrote:
On Oct 20, 6:30*pm, AMuzi wrote:

jay wrote:
On Oct 19, 3:41 pm, somebody wrote:
On Sun, 18 Oct 2009 14:31:30 -0500, AMuzi wrote:
somebody wrote:
I'm thinking of using some Shimano BR-550's on a road bike with Alex
DM-18 rims. *I can pick one of several fixed straddle cables. *Which
one?
Is it related to rim width, where we want length that produces a
specific angle based on brake model? *Does that mean the geometry
won't be quite right when switching to another rim? *I checked the
Sheldon stuff but don't have enough experience to pick the right one.
Adjustment:
http://www.sheldonbrown.com/canti-trad.html#yoke
The brakes:
http://www.sheldonbrown.com/harris/c...ers/index.html
You want the size which ends with a 90-degree angle as the
pads touch. That varies by brake stud position and rim
width. Some brakes allow lateral pad adjustment which can
help to get that just right with various LinkWire sizes.
That's it. *The brakes came with two different straddle cable sizes;
the previous owner worked at a shop and must *have swapped in what
worked on his bike. *That means I can try each and check the angle..


How are Shimano straddle/yoke cables measured? *Is it base on the
length that sticks out of the middle?


Thanks!


How are Shimano straddle/yoke cables measured? *Is it base on the
length that sticks out of the middle?


Thatís *good question!
After measuring several straddle links, Iíve come the conclusion that
itís the length of exposed cable from where it exitís the center
device to where it disappears into the lead casting @ the other end.
It isnít the same as the C-C distance, & therefore not usable in trig
calculations. However it isnít necessary to do any trig calculations
to try to get the optimum length.
As Andrew so succinctly pointed out the goal is to get the length such
that the straddle cables make a 90 deg or slightly smaller angle when
the pads hit the rim. Thatís w/ the angle measured @ the point where
the line from the pivot point of the brake arm intersects the cable
attachment, w/ the cable running to the center device as the other
line making the angle.
However, so far so I know itís usually impossible to get a 90 or 90
deg. angle w/ the ďnarrowĒ or ďup rightĒ type of cantilevere arms. The
angle usually ends up more oblique that 90 deg. Therefore the idea is
to *get an angle that is as close to 90 deg. While still clearing the
tire, fenders, racks, etc. Itís quite easy to get this 90 deg. or w/
the older style wide cantilevers such as ďPaulísĒ.
The idea of using straddle links in lieu for a single straddle cable
was to keep the straddle cable from getting caught on Mt.B. tire knobs
& tossing the rider over the bars in case of the primary brake cable
severing. I donít think this is much of a problem w/ relatively smooth
road tires, & therefore use a plain straddle cable on road bikes for
the greater ease of optimizing geometry.


The use of non threaded brake pad posts (or smooth posts) allows one
to extend the pads of upright arms further from the brake arm to
improve the angle of the straddle cable to brake arm. Doing this,
however brings on other problems. These are increased chance of brake
squeal, & the difficulty of adjusting smooth arm pads. In my
experience the rotating tabs that set toe-in & all the other pad
adjustments, are made of plastic that has to be torqued very tight.
This torque causes the plastic to deform creating a crease where the
pad post is. This isnít so bad when it is the 1st *time the brakes are
set up, but subsequent adjustments make it just about impossible to
keep the pad post from being captured by this crease. There are work
arounds, but are a pain too. I donít remember all the smooth pad posts
Iíve worked on. There may be some that donít have these adjustability
problems.
I would appreciate knowing which, if any, they are.


It's not just knobby tires. A transverse will grab any tire
and likely injure (kill?) the rider in the event of a failed
main wire.


It's good practice to ensure there's a mudguard, lamp
bracket or something between transverse and tire on a
non-LinkWire setup. You can argue helmets but not this.


Agreed--and link wires don't make you look like a Fred, either!


You can turn a regular straddle cable and hanger into a link-wire
setup by adding a bit of brake housing and rotating the straddle
hanger 120 degrees. Long cable goes through straddle hanger, then
housing, to clamps on one brake arm; short cable goes from other brake
arm to clamp bolt on straddle hanger.

Might make you look more of a Fred though.

-pm
  #9  
Old October 21st 09, 01:49 PM posted to rec.bicycles.tech
Qui si parla Campagnolo Qui si parla Campagnolo is offline
Banned
 
First recorded activity by CycleBanter: Jul 2006
Posts: 3,259
Default Q: Shimano cantilever straddle cable length?

On Oct 18, 7:41*am, somebody wrote:
I'm thinking of using some Shimano BR-550's on a road bike with Alex
DM-18 rims. *I can pick one of several fixed straddle cables. *Which
one?

Is it related to rim width, where we want length that produces a
specific angle based on brake model? *Does that mean the geometry
won't be quite right when switching to another rim? *I checked the
Sheldon stuff but don't have enough experience to pick the right one.

Thanks!

Adjustment:http://www.sheldonbrown.com/canti-trad.html#yoke

The brakes:http://www.sheldonbrown.com/harris/c...ers/index.html


Use one of these and give the one piece things the heave-ho.

http://www.bikeman.com/Cyclocross_St..._Carriers.html
  #10  
Old October 22nd 09, 04:10 AM posted to rec.bicycles.tech
Frank Krygowski[_2_]
external usenet poster
 
Posts: 6,586
Default Q: Shimano cantilever straddle cable length?

On Oct 21, 8:49*am, Qui si parla Campagnolo
wrote:

Use one of these and give the one piece things the heave-ho.

http://www.bikeman.com/Cyclocross_St..._Carriers.html


My touring bike has cable carriers like that, but with a built in
quick release lever. They're handy.

I'd like those on our tandem, since I switched to levers with no quick
release, but I've been unable to locate any.

Anyone know where I can get them?

- Frank Krygowski
 




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