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Brake Trouble / Road Bike



 
 
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  #1  
Old July 23rd 05, 05:10 PM
Rob
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Default Brake Trouble / Road Bike

Hello.

I just changed the brake cable on my old Myata Road bike..it has Shimano 105
Brakes when I apply the rear brake the one pad stays on the rim it does not
spring back into place the brake levers are also 105 AERO they are not STI
how can I fix this problem ? are I installing the cable wrong ?


Thanks

Rob Wille


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  #2  
Old July 23rd 05, 06:20 PM
Hank Wirtz
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Default Brake Trouble / Road Bike

"Rob" wrote in news:MZtEe.21990$%[email protected]:

Hello.

I just changed the brake cable on my old Myata Road bike..it has
Shimano 105 Brakes when I apply the rear brake the one pad stays on
the rim it does not spring back into place the brake levers are also
105 AERO they are not STI how can I fix this problem ? are I
installing the cable wrong ?


Thanks

Rob Wille




Probably not anything to do with the cable, other then the act of
installing it...The mounting bolt has likely been turned slightly, which
can happen when doing brake work.

You can sometimes recenter the calipers by turning the mounting nut, but be
careful you're not loosening them, There may be wrench flats on the bolt by
which to center it. Depending on their size, you may be able to use a cone
wrench, or if the flats are smaller, Park has a special wrench for this.
(http://www.parktool.com/tools/OBW_2.shtml) And be prepared to do fine-
tuning. Because of the mechanics of sidepull brakes, it can look centered,
but after a few applications of the brakes, it can get out of whack again,
which can be frustrating. If at first you don't succeed...

-HW
  #3  
Old July 23rd 05, 06:23 PM
Robin Hubert
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Default Brake Trouble / Road Bike

Rob wrote:
Hello.

I just changed the brake cable on my old Myata Road bike..it has Shimano 105
Brakes when I apply the rear brake the one pad stays on the rim it does not
spring back into place the brake levers are also 105 AERO they are not STI
how can I fix this problem ? are I installing the cable wrong ?


Thanks

Rob Wille



The problem is your (lack of) punctuation. Or isn't you?

Please answer these questions:

- Did you replace the inner wire only, or did you also replace the outer
(housing)?
- If you installed housing, did you cut it cleanly?
- Is it possible you kinked the cable?
- Have you pulled the cable out to have a look?
- Did you mess around with the caliper?
- How does the brake caliper behave without the cable attached (squeeze it)?

Please try to use punctuation it is really nice I mean people don't like
reading stuff without it the right thing you are more likely to get
answers don't be stubborn what am I doing?


Robin (message lost in the delivery) Hubert
  #4  
Old July 23rd 05, 06:29 PM
Robin Hubert
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Posts: n/a
Default Brake Trouble / Road Bike

Robin Hubert wrote:
Rob wrote:

Hello.

I just changed the brake cable on my old Myata Road bike..it has
Shimano 105 Brakes when I apply the rear brake the one pad stays on
the rim it does not spring back into place the brake levers are also
105 AERO they are not STI how can I fix this problem ? are I
installing the cable wrong ?


Thanks

Rob Wille


The problem is your (lack of) punctuation. Or isn't you?

Please answer these questions:

- Did you replace the inner wire only, or did you also replace the outer
(housing)?
- If you installed housing, did you cut it cleanly?
- Is it possible you kinked the cable?
- Have you pulled the cable out to have a look?
- Did you mess around with the caliper?
- How does the brake caliper behave without the cable attached (squeeze
it)?

Please try to use punctuation it is really nice I mean people don't like
reading stuff without it the right thing you are more likely to get
answers don't be stubborn what am I doing?


Robin (message lost in the delivery) Hubert


Yes, I am an ass.

Robin (not afraid of the truth) Hubert
  #6  
Old July 25th 05, 06:53 PM
[email protected]
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Default Brake Trouble / Road Bike

Rob Wille :

I just changed the brake cable on my old Miyata Road bike... When I
apply the Shimano 105 rear brake, one pad stays on the rim and does
not spring back when released. The brake levers are also 105 AERO
and not STI. How can I fix this problem? Am I installing the cable
wrong?


It's not the cable! Dual Pivot brakes were introduced to prevent the
asymmetric pad movement you describe. You'll notice that the return
spring slides in the caliper when the brake is used. This sliding
assumes that both spring ends are perfectly lubricated, which they are
not. Therefore, brake pads in single pivot, and even centerpull
brakes, generally do not retract equally after use in rain or dusty
terrain.

Unfortunately, bicycle repair shops, unaware of the cause, use hammers
and punches to bend the offending spring or repeatedly rotate the
center bolt instead of cleaning the contact and giving it a drop of
oil. Just a drop of oil is often enough. Hold the pad that moves
readily against the rim with the thumb while pumping the brake leaver
to get the other one freed up.

http://www.sheldonbrown.com/brandt/brakes.html

Thanks


Jobst Brandt
  #7  
Old July 25th 05, 08:33 PM
Sheldon Brown
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Default Brake Trouble / Road Bike

Rob Wille wrote:

I just changed the brake cable on my old Miyata Road bike... When I
apply the Shimano 105 rear brake, one pad stays on the rim and does
not spring back when released. The brake levers are also 105 AERO
and not STI. How can I fix this problem? Am I installing the cable
wrong?


Jobst wrote:

It's not the cable!


Actually, it could be. If the loop of cable running from the back end
of the top tube to the brake caliper is too short, and possibly even if
it's too long, it can do this.

See: http://sheldonbrown.com/cables for tips on cable installation.

Dual Pivot brakes were introduced to prevent the
asymmetric pad movement you describe.


But he doesn't have those.

You'll notice that the return
spring slides in the caliper when the brake is used. This sliding
assumes that both spring ends are perfectly lubricated, which they are
not. Therefore, brake pads in single pivot, and even centerpull
brakes, generally do not retract equally after use in rain or dusty
terrain.


Shimano SLR calipers use nylon or Teflon pads that the spring bumps
against, which generally don't reqire wet lubrication.

These are the finest single-pivot calipers ever made. I've got these on
my fixed gear tandem...

Unfortunately, bicycle repair shops, unaware of the cause, use hammers
and punches to bend the offending spring


That technique was appropriate for some older sidepulls, models dating
from the early '70s and older, and was the only way to regulate the
centering of the calper.

or repeatedly rotate the center bolt


Campagnolo invented the center bolt with wrench flats to permit it to be
turned/held with a cone wrench for correct centering. This was a major
breakthrough.

For the Shimano single-pivot sidepulls, the end of the center-bolt is
the point to turn/hold, using either a 5 mm Allen wrench or a 12 mm box
wrench. Best to loosen the mounting nut, turn the center bolt to center
the caliper, then tighten the mounting nut while holding the center bolt
from turning.

instead of cleaning the contact and giving it a drop of
oil. Just a drop of oil is often enough.


The oil is the way to go for calipers that have metal/metal contact
between the spring and the arm.

Sheldon "Symmetry" Brown
+----------------------------------------------------------+
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| but it is always the strongly marked feature of all |
| religions established by law. |
| Take away the law-establishment, and every religion |
| re-assumes its original benignity. |
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+----------------------------------------------------------+
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Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
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http://captainbike.com http://sheldonbrown.com

  #8  
Old July 25th 05, 11:41 PM
Helmut Springer
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Default Brake Trouble / Road Bike

Sheldon Brown wrote:
Shimano SLR calipers use nylon or Teflon pads that the spring bumps
against, which generally don't reqire wet lubrication.


I used DuraAce 7402 (the last single pivot DuraAce) with those pads
and they went off center when dirty...


These are the finest single-pivot calipers ever made. I've got


....while my SunTour GPX single pivot with two internal springs stay
centered, regardless of dirt. YMMV, mine does.

--
MfG/Best regards
helmut springer
  #9  
Old July 26th 05, 02:24 AM
[email protected]
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Posts: n/a
Default Brake Trouble / Road Bike

Sheldon Brown writes:

I just changed the brake cable on my old Miyata Road bike... When
I apply the Shimano 105 rear brake, one pad stays on the rim and
does not spring back when released. The brake levers are also 105
AERO and not STI. How can I fix this problem? Am I installing
the cable wrong?


It's not the cable!


Actually, it could be. If the loop of cable running from the back
end of the top tube to the brake caliper is too short, and possibly
even if it's too long, it can do this.


Let's assume that much about brake adjustment is understood. tension
in the cable should have little effect on centering, at least to the
amount that they might not move equally.

See: http://sheldonbrown.com/cables for tips on cable installation.


Dual Pivot brakes were introduced to prevent the asymmetric pad
movement you describe.


But he doesn't have those.


Who said he had dual pivot brakes? I only mentioned that because this
is a classic problem in single pivot brakes.

You'll notice that the return spring slides in the caliper when the
brake is used. This sliding assumes that both spring ends are
perfectly lubricated, which they are not. Therefore, brake pads in
single pivot, and even centerpull brakes, generally do not retract
equally after use in rain or dusty terrain.


Shimano SLR calipers use nylon or Teflon pads that the spring bumps
against, which generally don't require wet lubrication.


I installed Teflon sleeves in my Campagnolo brakes in the 1970's and
realized that the effect was minimal. We wouldn't have dual pivot
brakes today if plastic sleeves were an adequate fix for that problem.

These are the finest single-pivot calipers ever made. I've got these on
my fixed gear tandem...


Unfortunately, bicycle repair shops, unaware of the cause, use hammers
and punches to bend the offending spring


That technique was appropriate for some older sidepulls, models dating
from the early '70s and older, and was the only way to regulate the
centering of the caliper.


I don't believe it was ever appropriate. The anchor bolt on those
brakes could be rotated and the springs lubricated just the same as on
later more expensive brakes. It was on Universal side pull brakes
that I first recognized the problem and cringed when I saw the hammer
routine.

or repeatedly rotate the center bolt


Campagnolo invented the center bolt with wrench flats to permit it
to be turned/held with a cone wrench for correct centering. This
was a major breakthrough.


As I said, you could rotate the center bolt without the 13mm wrench
flats and I did. It was one of my disappointments with Campagnolo
because since those days I designed a return spring that does not have
(cosine error) slip when returning the caliper. It's coil is
concentric with the center bolt and does not have this problem.

For the Shimano single-pivot sidepulls, the end of the center-bolt
is the point to turn/hold, using either a 5 mm Allen wrench or a 12
mm box wrench. Best to loosen the mounting nut, turn the center
bolt to center the caliper, then tighten the mounting nut while
holding the center bolt from turning.


instead of cleaning the contact and giving it a drop of oil. Just
a drop of oil is often enough.


Since the spring does not change, logically only cleaning and
lubrication is the right response. It has nothing to do with whether
there is a solid lubricant at the spring contact.

The oil is the way to go for calipers that have metal/metal contact
between the spring and the arm.


Sheldon "Symmetry" Brown


Dual pivot brakes are not symmetrical and that's where we're at!

Jobst Brandt
 




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