Why do my cantilever brakes do this?



T

TomYoung

Guest
Hi all:

My Surly Long Haul Trucker is the first bike I've owned with
cantilever brakes so maybe I'm missing something here.

Just about every time I release the brake straddle wire to move the
brakes out of the way for wheel removal the two pads don't come back
into position on either side of the wheel when I put the straddle wire
back into place. Most of the time I have to tweak the spring force on
one or the other cantilevers to get the two pads to come back into a
balanced position "at rest." They've acted this way since day one
after I put the bike together a little over a year ago and this funky
action continues to this day.

When I put the bike together I greased the posts the cantilevers ride
on properly - I think - and it seems like if lubrication was an issue
here that the brakes wouldn't come back centered at rest in normal
operation, but they do, after I do my tweaks.

I don't know why undoing the straddle wire and then reattaching it
changes things, but it sure does. Any thoughts on what's causing this
behavior?

Brakes are TekTro 992A canti's attached to TekTro 100A levers.

TIA.

Tom Young
 
L

landotter

Guest
On May 2, 10:50 am, TomYoung <[email protected]> wrote:
> Hi all:
>
> My Surly Long Haul Trucker is the first bike I've owned with
> cantilever brakes so maybe I'm missing something here.
>
> Just about every time I release the brake straddle wire to move the
> brakes out of the way for wheel removal the two pads don't come back
> into position on either side of the wheel when I put the straddle wire
> back into place. Most of the time I have to tweak the spring force on
> one or the other cantilevers to get the two pads to come back into a
> balanced position "at rest."


Obvious check: see that you're seating the wheel in the fork the same
way each time with the QR on the same side. If you haven't done the
rear brake straddle wire try releasing and attaching it and see if the
same phenomena happens. Make sure to squeeze the lever after
reattaching so the springs do their job centering. It's also worth
cleaning the posts well and regreasing. I've had some nasty factory
residue on canti studs.
 
?

_

Guest
On Fri, 2 May 2008 08:50:00 -0700 (PDT), TomYoung wrote:

> Hi all:
>
> My Surly Long Haul Trucker is the first bike I've owned with
> cantilever brakes so maybe I'm missing something here.
>
> Just about every time I release the brake straddle wire to move the
> brakes out of the way for wheel removal the two pads don't come back
> into position on either side of the wheel when I put the straddle wire
> back into place. Most of the time I have to tweak the spring force on
> one or the other cantilevers to get the two pads to come back into a
> balanced position "at rest." They've acted this way since day one
> after I put the bike together a little over a year ago and this funky
> action continues to this day.
>
> When I put the bike together I greased the posts the cantilevers ride
> on properly - I think - and it seems like if lubrication was an issue
> here that the brakes wouldn't come back centered at rest in normal
> operation, but they do, after I do my tweaks.
>
> I don't know why undoing the straddle wire and then reattaching it
> changes things, but it sure does. Any thoughts on what's causing this
> behavior?
>
> Brakes are TekTro 992A canti's attached to TekTro 100A levers.
>
> TIA.
>
> Tom Young


Perhaps you are placing the wire off-centre in the hook.

What happens if you leave them uncentred after re-attaching the wire, then
squeeze the brakes, then release them?
 
L

landotter

Guest
On May 2, 11:14 am, _ <[email protected]>
wrote:

> Perhaps you are placing the wire off-centre in the hook.


Oryx brakes use a link wire, not a traditional hook:

http://www.lickbike.com/productpage.aspx?PART_NUM_SUB='1255-00'
 
T

TomYoung

Guest
On May 2, 9:05 am, landotter <[email protected]> wrote:
> On May 2, 10:50 am, TomYoung <[email protected]> wrote:
>
> > Hi all:

>
> > My Surly Long Haul Trucker is the first bike I've owned with
> > cantilever brakes so maybe I'm missing something here.

>
> > Just about every time I release the brake straddle wire to move the
> > brakes out of the way for wheel removal the two pads don't come back
> > into position on either side of the wheel when I put the straddle wire
> > back into place. Most of the time I have to tweak the spring force on
> > one or the other cantilevers to get the two pads to come back into a
> > balanced position "at rest."

>
> Obvious check: see that you're seating the wheel in the fork the same
> way each time with the QR on the same side. If you haven't done the
> rear brake straddle wire try releasing and attaching it and see if the
> same phenomena happens. Make sure to squeeze the lever after
> reattaching so the springs do their job centering. It's also worth
> cleaning the posts well and regreasing. I've had some nasty factory
> residue on canti studs.


Yep, always put the front wheel in the same way and the problem exists
front and back. I do "the squeeze" after putting things back together
and that's what reveals the unbalanced situation. I probably will
pull things apart for a relube.

Thanks.
 
L

landotter

Guest
On May 2, 11:51 am, TomYoung <[email protected]> wrote:
> On May 2, 9:05 am, landotter <[email protected]> wrote:
>
>
>
> > On May 2, 10:50 am, TomYoung <[email protected]> wrote:

>
> > > Hi all:

>
> > > My Surly Long Haul Trucker is the first bike I've owned with
> > > cantilever brakes so maybe I'm missing something here.

>
> > > Just about every time I release the brake straddle wire to move the
> > > brakes out of the way for wheel removal the two pads don't come back
> > > into position on either side of the wheel when I put the straddle wire
> > > back into place. Most of the time I have to tweak the spring force on
> > > one or the other cantilevers to get the two pads to come back into a
> > > balanced position "at rest."

>
> > Obvious check: see that you're seating the wheel in the fork the same
> > way each time with the QR on the same side. If you haven't done the
> > rear brake straddle wire try releasing and attaching it and see if the
> > same phenomena happens. Make sure to squeeze the lever after
> > reattaching so the springs do their job centering. It's also worth
> > cleaning the posts well and regreasing. I've had some nasty factory
> > residue on canti studs.

>
> Yep, always put the front wheel in the same way and the problem exists
> front and back. I do "the squeeze" after putting things back together
> and that's what reveals the unbalanced situation. I probably will
> pull things apart for a relube.


Yup, do that--then set your springs both at max tension, and center
them this time by releasing tension on one side or the other--this
will also give you a nice feel at the lever.
 
T

TomYoung

Guest
On May 2, 9:21 am, landotter <[email protected]> wrote:
> On May 2, 11:14 am, _ <[email protected]>
> wrote:
>
> > Perhaps you are placing the wire off-centre in the hook.

>
> Oryx brakes use a link wire, not a traditional hook:
>
> http://www.lickbike.com/productpage.aspx?PART_NUM_SUB='1255-00'


Ah, maybe this *is* the source of the problem! The TekTro's do use a
link wire, but the button on the link wire has two slots for the main
brake cable to ride ride in: one slot allows the cable to move freely
through the button and the other slot locks the cable in place.
Perhaps when I release the free end of the link wire I'm inadvertently
moving the main cable over to the "free movement" slot, where it moves
from its original position, but the act of re-attaching the link wire
is putting the main cable over in the "locked" slot, where it's off-
center! I don't think I've ever focused on this possibility when I've
removed and then re-attached the link wire; I think that I've always
just assumed - without looking - that the main cable stays in the
"locked" position.

I'll test this hypothesis this evening. I have a feeling the two of
you have solved the problem!

Thanks.
 
L

landotter

Guest
On May 2, 12:02 pm, TomYoung <[email protected]> wrote:
> On May 2, 9:21 am, landotter <[email protected]> wrote:
>
> > On May 2, 11:14 am, _ <[email protected]>
> > wrote:

>
> > > Perhaps you are placing the wire off-centre in the hook.

>
> > Oryx brakes use a link wire, not a traditional hook:

>
> >http://www.lickbike.com/productpage.aspx?PART_NUM_SUB='1255-00'

>
> Ah, maybe this *is* the source of the problem! The TekTro's do use a
> link wire, but the button on the link wire has two slots for the main
> brake cable to ride ride in: one slot allows the cable to move freely
> through the button and the other slot locks the cable in place.
> Perhaps when I release the free end of the link wire I'm inadvertently
> moving the main cable over to the "free movement" slot, where it moves
> from its original position, but the act of re-attaching the link wire
> is putting the main cable over in the "locked" slot, where it's off-
> center! I don't think I've ever focused on this possibility when I've
> removed and then re-attached the link wire; I think that I've always
> just assumed - without looking - that the main cable stays in the
> "locked" position.
>
> I'll test this hypothesis this evening. I have a feeling the two of
> you have solved the problem!


Woohoo, a buncha monkeys just typed Othello!

I do recommend the spring tension thing anyway--I really like the feel
of a snappy lever.
 
I

It's Chris

Guest
Does the straddle anchor hav a pully, or just a guideway?

if it's the latter, you're probably not replacing it at exactly the same
spot on the straddle cable each time. Not unusual, but it can be
irritating.

Try this, next time you rehitch it, if it isn't centered, try moving the
anchor slightly to wards the side that is furthest from the rim until it
does, then give the brake lever a squeee and see if it stays centered.

- -
Compliments of:
"Your Friendly Neighborhood Wheelman"

If you want to E-mail me use:
ChrisZCorner "at" webtv "dot" net

My website:
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