Best Brake Cable brand?
RS
stretches the least or is just generally the best type of cable?
thanks
* * Chas
"RS" <r_sch...@comcast.net> wrote in message
news:5oednQjaDvRBBNjY...@comcast.com...
Shimano makes some great stainless steel brake and shifter cables.
Chas.
Qui si parla Campagnolo
Jagwire brand, from Quality Bike parts, a distributor. Not expensive,
works well. shimano and Campag branded, you pay extra $ for the name.
Werehatrack
>Is there a brand or type of brake cable, especially for the rear brake, that
>stretches the least or is just generally the best type of cable?
It's a matter of opinion, but here's what I've found works for me:
I buy stainless mandrel-drawn wires (they're smoother on the outside
than plain wire, and don't rust) and use them with lined cable housing
from a manufacturer with a good reputation like Jag or Shimano. I
have not found that the teflon-coated inner wires work any better than
the plain ones, and to me they seem to raise the finger effort
required. Your experience may vary; others will have their own
opinions and advice.
One other point: Unless you are miles from home and there is no
alternative, I would recommend against buying any cable sold under the
Bell name, and/or any cable sold by a mass-market-oriented discount
sporting goods store such as Academy, Sports Authority, Dick's and the
like. They tend to be supplied with unlined housing that's made from
round wire, and their cable tends to be either plain or thinly plated
steel without the benefit of the smoothing mentioned above. I have
dramatically reduced the finger effort required in braking on several
bikes by just replacing brand-new Bell cables and housings with decent
ones from a more reputable supplier.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.
carl...@comcast.net
<pe...@vecchios.com> wrote:
Dear Peter,
BikeToolsEtc also offers a wide array of Jagwire cables (and others):
http://www.biketoolsetc.com/index.cgi?id=745689442538&c=Repair-Parts&sc=Cable-and-Housing
or http://tinyurl.com/ydfnq2
Cheers,
Carl Fogel
jobst....@stanfordalumni.org
Elastic elongation of brake cables (stretch) is not enough to be felt,
but if you want to minimize that which there is, buy the cable with
the largest cross section. Stainless steel having the same modulus of
elasticity as other steel cables, and made by the same process, makes
no difference except being more expensive. A brake cable should be
lubricated anyway, which prevents rust.
Stretch, or more precisely flex, occurs in the caliper and brake pad.
and possibly a tiny amount in the hand lever. Cable housing is made
of a coiled steel wire that is in contact around the inside of a cable
bend and has full contact on straight runs.
Neither the cable nor the housing yields in use so there is no
permanent "stretching". Some length change occurs when curves in a
brake cable change shape under load, but even that produces negligible
length change (cosine error).
I think you'll find that cable motion at the brake caliper is
essentially the same as at the hand lever. It is the caliper and
brake pads that deform and cause "sponge".
When installing a new cable, wipe grease on the cable with the fingers
before inserting it in the cable housing.
Jobst Brandt
frkr...@gmail.com
jobst....@stanfordalumni.org wrote:
> Robert Schiller writes:
>
> > Is there a brand or type of brake cable, especially for the rear
> > brake, that stretches the least or is just generally the best type
> > of cable?
>
>
> Stretch, or more precisely flex, occurs in the caliper and brake pad.
>
> Neither the cable nor the housing yields in use so there is no
> permanent "stretching". Some length change occurs when curves in a
> brake cable change shape under load, but even that produces negligible
> length change (cosine error).
>
> I think you'll find that cable motion at the brake caliper is
> essentially the same as at the hand lever. It is the caliper and
> brake pads that deform and cause "sponge".
Bends in cable wires are a sometimes unappreciated source of lost
motion. I've found this to be common with center pull brakes, such as
ordinary cantilevers, but it can happen with other types.
When cantilever straddle cables are not pre-bent to run in a straight
line from the saddle to the cantilever arm, they hold the arms slightly
closed. The brakes will have to be adjusted so they are open wider to
prevent scraping on imperfectly trued rims. Then when levers are
gripped, some cable motion is lost to just straightening that curve, so
extra lever travel is required. The same can happen with direct pull
cantilevers (V-brakes). It's less common with sidepulls, since the
free run of the inner wire is naturally straight, much shorter and more
protected.
You can see examples of such bent cable runs at the bottom photo in
http://sheldonbrown.com/cantilever-geometry.html
and in the "direct pull" photo at the top of
http://sheldonbrown.com/cantilever-adjustment.html
What you want are straight lines, as in the 1992 drawing by Sheldon
about halfway down http://sheldonbrown.com/cantilever-geometry.html
I take the curves out of canti straddle cables, etc. using pliers. I
find it improves the feel of cantilevers quite a bit.
- Frank Krygowski
carl...@comcast.net
Dear Jobst,
For what it's worth, at least one poster can tell the difference
between the stretch in different cable lays:
[Carl asked:]
So if the 19-strand and the 49-strand cables are roughly the same
thickness, then the 49-strand cables must use much thinner strands,
and it's the use of many thin stands that makes them more flexible and
presumably gives them a smoother texture?
[Chalo replied:]
That's why they are more supple, but their texture is coarser (since
they are essentially seven-strand cables made of wound filaments).
[Carl asked:]
Very timidly and trying not to start any arguments, but am I wrong in
thinking that I remember emphatic statements from other posters that
cables don't stretch?
[Chalo replied:]
I've seen the assertions myself. Whether the elasticity of a
19-strand cable is significant within the relevant range of tensions I
simply don't know. However, the additional stretch in a 7x7 rope lay
cable is easy to discern. I have assumed that this is due to relative
movement of the 49-strand cable's less compacted filaments.
http://groups.google.com/group/rec.bicycles.tech/msg/20729d1569cf30be
I expect that most of the cables mentioned in this thread will be 19
strand and not the 49 strand.
Cheers,
Carl Fogel
Ozark Bicycle
While lined housing and 'smoother' cables can make a diffference, an
equally important point is properly sizing the cable housing and
'dressing' the ends to eliminate burrs in the cable path. Cheaper cable
sets are usually found on cheaper bikes, which rarely receive the
needed attention to detail for smoothest operation. Given the proper
attention and a bit of grease, cheap cables can work quite well.
jobst....@stanfordalumni.org
>>> Is there a brand or type of brake cable, especially for the rear
>>> brake, that stretches the least or is just generally the best type
>>> of cable?
>> Elastic elongation of brake cables (stretch) is not enough to be
>> felt, but if you want to minimize that which there is, buy the
>> cable with the largest cross section. Stainless steel having the
>> same modulus of elasticity as other steel cables, and made by the
>> same process, makes no difference except being more expensive. A
>> brake cable should be lubricated anyway, which prevents rust.
>> Stretch, or more precisely flex, occurs in the caliper and brake
>> pad. and possibly a tiny amount in the hand lever. Cable housing
>> is made of a coiled steel wire that is in contact around the inside
>> of a cable bend and has full contact on straight runs.
>> Neither the cable nor the housing yields in use so there is no
>> permanent "stretching". Some length change occurs when curves in a
>> brake cable change shape under load, but even that produces
>> negligible length change (cosine error).
>> I think you'll find that cable motion at the brake caliper is
>> essentially the same as at the hand lever. It is the caliper and
>> brake pads that deform and cause "sponge".
>> When installing a new cable, wipe grease on the cable with the
>> fingers before inserting it in the cable housing.
> For what it's worth, at least one poster can tell the difference
> between the stretch in different cable lays:
======================================================================
> [Carl asked:]
> So if the 19-strand and the 49-strand cables are roughly the same
> thickness, then the 49-strand cables must use much thinner strands,
> and it's the use of many thin stands that makes them more flexible
> and presumably gives them a smoother texture?
> [Chalo replied:]
> That's why they are more supple, but their texture is coarser (since
> they are essentially seven-strand cables made of wound filaments).
> [Carl asked:]
> Very timidly and trying not to start any arguments, but am I wrong
> in thinking that I remember emphatic statements from other posters
> that cables don't stretch?
> [Chalo replied:]
> I've seen the assertions myself. Whether the elasticity of a
> 19-strand cable is significant within the relevant range of tensions
> I simply don't know. However, the additional stretch in a 7x7 rope
> lay cable is easy to discern. I have assumed that this is due to
> relative movement of the 49-strand cable's less compacted filaments.
> http://groups.google.com/group/rec.bicycles.tech/msg/20729d1569cf30be
> I expect that most of the cables mentioned in this thread will be 19
> strand and not the 49 strand.
======================================================================
I see no explanation in that exchange of what stretches and how much.
There is no difference in conventional and super-flex cable except
flexibility (and cost). The higher strand count arises because the
flex cable is wound of cables instead of filaments, the purpose being
to increase flexibility. These were first seen on bar end shifters
because a stiff cable would interfere with steering, making no-hands
riding more difficult. You may recall that these shift cables also
used bare chromed steel housings to reduce housing stiffness.
Both types of cable are wound with no clearance between strands. That
means that one is no more compact than the other, the filaments having
to be close packed or the cable would act as a coil spring, something
for which a cable is not intended. Cables are helically wound to make
them constant length regardless of bend. Every strand must pass
through both the inside and outside of a bend so that all strands bear
the load without affecting cable length.
That is why STI constant length shift cable housing uses long helical
steel strands while conventional brake cable housings uses a coil.
Shift cable is sensitive to housing length because even small changes
can interfere with derailleur position, whereas brake force is
unaffected by it. Shifting being a position function and braking a
force function.
In sight of the experiments you have pursued in other respects I would
have expected you to hang a 100lb weight on a brake cable to show the
elongation a strong brake grasp can produce. Brake hand levers with
their 4:1 mechanical advantage can be grasped with more than 20lbs.
Jobst Brandt
Ozark Bicycle
jobst.bra...@stanfordalumni.org wrote to C. Fogel:
- on brake cable stretch -
>
> In sight of the experiments you have pursued in other respects I would
> have expected you to hang a 100lb weight on a brake cable to show the
> elongation a strong brake grasp can produce. Brake hand levers with
> their 4:1 mechanical advantage can be grasped with more than 20lbs.
>
LOL!!
Werehatrack
<bicycle...@ozarkbicycleservice.com> wrote:
There's "inexpensive, serviceable" and then there's "cheap crap".
I've used generic cables and housings from the two nearby bike shops
with good results, but the visually similar stuff from Bell was an
entirely different matter. It was crap. Two of the bikes I
"upgraded" into decent brake function by merely replacing the
new-but-crap Bell cables had Bell housing that had been cleanly and
squarely cut and installed with good, centered ferrules...and they
still didn't work worth a damn. Swapping out to Shimano housing alone
reduced the pull effort, and replacing the wire as well produced a
brake that both operated at low effort and reliably returned to the
same rest opening dimensions. With the Bell cables, the brakes would
sometimes drag after being released, exactly as though there was a
burr or bent wire inside the housing somewhere...but the housing ends
on the Bell assemblies were cleanly cut, and the wires were as
straight when removed as they had been when they were put in. I think
that part of the problem was that the Bell wires were laterally
stiffer than the Jags, which caused them to be less compliant to the
cable routing path on bends.
After that rather educational afternoon's worth of work, I bought a
100ft box of Shimano brake housing and a big pack of Jagwire drawn
stainless cables. I'd rather spend a few bucks than put up with
something that won't work right, and a bulk buy of the good stuff got
me a better deal per each than I'd been getting at the lbs for
generics one at a time.
Ozark Bicycle
I've never (knowingly) workrd on a bike that was fitted with the Bell
cable/housing. I'm a bit surprised they would go out of their way to
package and sell stuff so completely at the bottom of the pile.
> Two of the bikes I
> "upgraded" into decent brake function by merely replacing the
> new-but-crap Bell cables had Bell housing that had been cleanly and
> squarely cut and installed with good, centered ferrules...and they
> still didn't work worth a damn. Swapping out to Shimano housing alone
> reduced the pull effort,
I wonder if there was a size mismatch, the Bell cables being a wee bit
too large for the Bell housing.
> and replacing the wire as well produced a
> brake that both operated at low effort and reliably returned to the
> same rest opening dimensions. With the Bell cables, the brakes would
> sometimes drag after being released, exactly as though there was a
> burr or bent wire inside the housing somewhere...but the housing ends
> on the Bell assemblies were cleanly cut, and the wires were as
> straight when removed as they had been when they were put in. I think
> that part of the problem was that the Bell wires were laterally
> stiffer than the Jags, which caused them to be less compliant to the
> cable routing path on bends.
That could well be a factor.
carl...@comcast.net
Dear Jobst,
I shouldn't have expected you to bother to read the rest of the post
that I linked to, much less the entire thread, so here's the spoon
feeding that you seem to expect.
You see, there are calculators for cable stretch from cable companies.
Chalo took the trouble to look at the one that I mentioned. Below is
the link to the cable stretch calculator and Chalo's comments, which
are as clear and to the point as ever:
[Carl's link to cable stretch calculator:]
http://www.spaceagecontrol.com/calcstre.htm?MA%5B0%5D=50&MA%5B2%5D=60...
or http://tinyurl.com/yxc4m9
[Chalo's comment on using the calculator:]
"When I enter values that would be characteristic of a rear brake
cable on one of my bikes (1.6mm dia, 200 lbf, and 38" length, I get
stretch quantities of about a quarter inch, roughly one third of the
usable range of a conventional brake lever. This is apart from
compression in the cable housing and flex at the anchor points. It
makes sense in the context of my experience with 7x7 cables."
http://groups.google.com/group/rec.bicycles.tech/msg/20729d1569cf30be
Cheers,
Carl Fogel
jim beam
> Robert Schiller writes:
>
>> Is there a brand or type of brake cable, especially for the rear
>> brake, that stretches the least or is just generally the best type
>> of cable?
>
> Elastic elongation of brake cables (stretch) is not enough to be felt,
rubbish
> but if you want to minimize that which there is, buy the cable with
> the largest cross section.
true, provided it's the area sum of the individual strands, not the
nominal cable section.
> Stainless steel having the same modulus of
> elasticity as other steel cables,
roughly.
> and made by the same process,
true
> makes
> no difference except being more expensive.
rubbish. stainless brake cables, just as with stainless spokes, are
significantly more fatigue resistant. your ignorance may mean you don't
care, but personally, i feel a /lot/ more happy riding with stainless
brake cable...
> A brake cable should be
> lubricated anyway, which prevents rust.
unless it's running in a plastic lined outer, in which case, some types
of lubrication can interact with the liner and gum up the works
significantly. besides, if it /is/ an unlined outer and it's lubed with
oil, it can attract grit and create famous jobstian "grinding paste"
wearing the cable rapidly.
>
> Stretch, or more precisely flex,
flex is bending. stretch is elongation. therefore, for the cable,
"more precisely" is stretch, not flex.
> occurs in the caliper and brake pad.
> and possibly a tiny amount in the hand lever.
that would be flex.
> Cable housing is made
> of a coiled steel wire that is in contact around the inside of a cable
> bend and has full contact on straight runs.
so? that's not relevant unless you want to describe how bending affects
apparent elongation in bowden cable.
>
> Neither the cable nor the housing yields in use so there is no
> permanent "stretching". Some length change occurs when curves in a
> brake cable change shape under load, but even that produces negligible
> length change (cosine error).
rubbish. a significant portion of apparent stretch is directly
attributable to the de facto length change of the outer as it bends.
adjust a brake cable so the pads just touch the rim, then note how well
the brake locks the wheel with a tiny extra cable bend. this is a well
known phenomenon. how come you don't seem to have a grip on this
subject? [rhetorical]
>
> I think you'll find that cable motion at the brake caliper is
> essentially the same as at the hand lever. It is the caliper and
> brake pads that deform and cause "sponge".
supposition is not fact. do the math for stretch under load, especially
for the much longer run of the rear brake cable.
>
> When installing a new cable, wipe grease on the cable with the fingers
> before inserting it in the cable housing.
not just any grease. the grease has to be inert with respect to the
liner or fouling problems occur if the liner dissolves. light silicone
usually does the trick.
jim beam
excellent and much more fatigue resistant that cheaper brands. if you
want make your own observations in this respect, get a jewelers loupe
and look at the cable surface. cheaper cable [jagwire] can have nics
and scratches in the strand wires which will be fatigue nucleation
points. for the quality brands, strand wire surface finish relatively
smooth and will last longer accordingly. [not to be confused with "die
drawn" cable which is smoother to the naked eye. die drawn is ok if the
initial material quality was sufficient.]
apparent "stretch" observed over time is wear of the cable inner into
the outer or its lining. best use quality outer that is plastic lined
and that is pre-lubed with inert grease [shimano or campy]. wear rate
is very low for these brands as material quality is high.
Johnny Sunset aka Tom Sherman
> Robert Schiller writes:
> ...
> Stretch, or more precisely flex, occurs in the caliper and brake pad.
> and possibly a tiny amount in the hand lever. Cable housing is made
> of a coiled steel wire that is in contact around the inside of a cable
> bend and has full contact on straight runs.
The late 1990's SRAM ESP flat bar levers had enough flex in the lever
mount to be visible. Some bikes with chain-stay mounted cantilever
brakes also have significant (i.e. visible) flexure of the stays when
the rear brake is applied forcefully.
--
Tom Sherman - Here, not there.
dookie
housing reinforced by stiff longitudinal wire. you have to cut the stuff
with a dremel, and it absolutely does not compress. brakes are mech disc in
front and cartridge-bearing v's w/brace in back. very responsive. i like
it a lot, but the housing runs are fairly short. no gears.
on the road, campy baby. chorus ergo 8-speed brakes & drivetrain, operated
via campy wire. traditional wound cable housing runs the length of the
frame for rear brake = squishy. otherwise fine. avid next time.
$0.02,
dookie
"RS" <r_sch...@comcast.net> wrote in message
news:5oednQjaDvRBBNjY...@comcast.com...
Michael Press
<bcqck2lqvqbkqgsd3...@4ax.com>,
carl...@comcast.net wrote:
Cable stretch should be expunged from the lexicon.
Replace with elastic deformation, cable system seating,
and yield.
--
Michael Press
G.T.
"dookie" <dookie@~obvious~dooksucks.com> wrote in message
news:JfA1h.18743$39.1...@southeast.rr.com...
> on the mtb, i'm using avid wires: a drawn, coated inner wire in lined
> housing reinforced by stiff longitudinal wire. you have to cut the stuff
> with a dremel,
Interesting, I just installed some myself for some Avid brakes. My diagonal
cutters worked fine.
Greg
jobst....@stanfordalumni.org
======================================================================
>>> [Carl asked:]
>>> [Chalo replied:]
>>> [Carl asked:]
>>> [Chalo replied:]
http://groups.google.com/group/rec.bicycles.tech/msg/20729d1569cf30be
> I shouldn't have expected you to bother to read the rest of the post
> that I linked to, much less the entire thread, so here's the spoon
> feeding that you seem to expect.
> You see, there are calculators for cable stretch from cable companies.
> Chalo took the trouble to look at the one that I mentioned. Below is
> the link to the cable stretch calculator and Chalo's comments, which
> are as clear and to the point as ever:
> [Carl's link to cable stretch calculator:]
> http://www.spaceagecontrol.com/calcstre.htm?MA%5B0%5D=50&MA%5B2%5D=60...
> or http://tinyurl.com/yxc4m9
> [Chalo's comment on using the calculator:]
> "When I enter values that would be characteristic of a rear brake
> cable on one of my bikes (1.6mm dia, 200 lbf, and 38" length, I get
> stretch quantities of about a quarter inch, roughly one third of the
> usable range of a conventional brake lever. This is apart from
> compression in the cable housing and flex at the anchor points. It
> makes sense in the context of my experience with 7x7 cables."
http://groups.google.com/group/rec.bicycles.tech/msg/20729d1569cf30be
How do you reconcile that with the statement:
# Relative to other error sources, elastic cable stretch generally
# creates am extremely small error in cable-actuated position
# transducers. For precision, low-cable-tension applications, the
# error is generally below 0.01% of the full scale range of the
# position transducer. This is because the rated cable strength of
# the cable is much greater than the load applied to the cable.
I think you are confusing constructional stretch with elastic stretch
(operating stretch). Chalo claims a cable stretch of 1/4" which
results in an inch at the hand lever (4:1 ratio) in addition to
elasticity of the caliper and pad which is the principal sponge felt
by a user. Therefore, his brakes don't work at all, because that
exceeds the stroke of the hand lever, considering that at least a
third of the stroke is used to take up pad clearance to the rim.
Something does not add up here.
Jobst Brandt
carl...@comcast.net
Dear Jobst,
I think that you are confusing mechanicl brake levers with electrical
transducers.
Cheers,
Carl Fogel
frkr...@gmail.com
> >
> >> "When I enter values that would be characteristic of a rear brake
> >> cable on one of my bikes (1.6mm dia, 200 lbf, and 38" length, I get
> >> stretch quantities of about a quarter inch, roughly one third of the
> >> usable range of a conventional brake lever. This is apart from
> >> compression in the cable housing and flex at the anchor points. It
> >> makes sense in the context of my experience with 7x7 cables."
carl...@comcast.net wrote:
>
> Dear Jobst,
>
> I think that you are confusing mechanicl brake levers with electrical
> transducers.
My thoughts on the above:
Chalo's 200 lb tension on the cable seems to be an extremely high
value. We know Chalo's a very large, very strong guy who would require
- and be able to deliver - high brake forces. But I think the typical
rider will never apply his full grip strength to the brake, unless the
brake system is defective.
FWIW, as part of a classroom design exercise, I had one of my students
squeeze an old Shimano drop bar brake lever as hard as he could. The
lever was held open by a machine screw acting as the cable would act.
The student had no problem causing the lever to yield and bend all the
way to the bar. He was a pretty strong guy, but not outrageously so.
It wouldn't be hard to measure the amount of lever motion at the bars.
As Jobst says, it's got several sources. If someone wants to evaluate
where lost motion comes from, they could eliminate one source after
another, using a game scale (or something similar) to apply a
consistent lever force.
For example, measure lever motion on the brake in normal condition;
then measure with the rim-to-pad clearance adjusted to zero;
then with the cables carefully straightened, as I described above;
then measure with steel blocks replacing rubber brake pads;
then measure with the caliper end of the cable fixed to the caliper end
of the housing, so you're seeing only the effects of the inner cable
and housing, including response to curvature;
then compute the inner wire's tension via lever geometry, and measure
the wire's stretch under that straight-line tension;
... and so on.
This would show what percentage of lost motion comes from different
effects. After that, the cable & housing test could be repeated with
different cables and housings, for direct comparison.
Through all this, I'd keep in mind that most brake applications are
pretty light, at least for road bikes. I've never bent my brake levers
in real life riding!
- Frank Krygowski
* * Chas
<frkr...@gmail.com> wrote in message
news:1162318129.6...@m7g2000cwm.googlegroups.com...
I have large strong front paws... ;-)
I've always installed new brake cables so that the brake pads are
touching or almost touching the rims, then I squeeze the brake levers as
hard as I can. This serves 2 functions, the first is a safety check on
the cables. I've had cable ends come off on several occasions during my
tests and this exercise saves me from an unpleasant surprise on the
road. The other initially stretches the cables enough so that my brakes
are adjust with the right amount of play so that I don't have to
readjust the cable length.
Chas.
carl...@comcast.net
[snip]
Dear Frank,
At the 4:1 ratio mentioned, a 50-lb squeeze should provide 200 lbs of
force, which is within the reach of most grown men.
Since the detail may be getting lost, Chalo's reply compared 7x7 laid
cable to 1x6x12 cable. He could feel roughly the stretch predicted by
the cable company's stretch calculator on 7x7, which is the stretchier
kind of cable.
I agree that good brakes shouldn't need the rider's full strength to
work well.
Cheers,
Carl Fogel
frkr...@gmail.com
Right. And in practice, the full rider's strength is almost never
applied. As long as the front brake is also being used, applying that
large a force to the rear brake lever would typically cause the rear
wheel to skid uselessly. And applying a force that large on the front
brake is generally impractical due to the chance of pitching over. So
computing cable stretch due to a 200 pound force is misleading.
I prefer brakes with mimimal lost motion, but I think the lost motion
that exists with most brakes comes from things other than the
stretching of the cable. I think items like cable misalignment (bends
instead of straight lines), hanger flex, brake arm flex, frame flex
(with cantis), etc. are much more important.
I think the situation is analogous to that for vertical "harshness" of
rear triangles. Once you measure the amount of vertical motion in the
tire, saddle, and perhaps seatpost, you see that the tiny amount of
vertical motion in _any_ rigid rear triangle is a minor effect. Going
from steel to aluminum to carbon fiber is a negligible change.
Likewise I think the elastic stretch in a brake cable is a minor
effect. Going from brand A cable to brand B cable will make a
negligible change in the lost motion.
But I admit, I haven't done the measurements I proposed.
- Frank Krygowski
Robin Hubert
> <frkr...@gmail.com> wrote in message
< big snip>
>>frkr...@gmail.com> wrote
>> Through all this, I'd keep in mind that most brake applications are
>> pretty light, at least for road bikes. I've never bent my brake
> levers
>> in real life riding!
>>
>> - Frank Krygowski
>>
>
> I have large strong front paws... ;-)
>
> I've always installed new brake cables so that the brake pads are
> touching or almost touching the rims, then I squeeze the brake levers as
> hard as I can. This serves 2 functions, the first is a safety check on
> the cables.
The more important function it serves is to seat the cable head and
housings into their stops.
>I've had cable ends come off on several occasions during my
> tests and this exercise saves me from an unpleasant surprise on the
> road.
Please tell me what is this unpleasantness.
>The other initially stretches the cables enough so that my brakes
> are adjust with the right amount of play so that I don't have to
> readjust the cable length.
Yes, well, "stretches" isn't what most people think. What's going on is
compression.
>
> Chas.
>
>
Robin Hubert
* * Chas
"Robin Hubert" <cv2...@hotmail.com> wrote in message
news:GFV1h.595$0r....@newsread1.news.pas.earthlink.net...< snip>
> > I have large strong front paws... ;-)
> >
> > I've always installed new brake cables so that the brake pads are
> > touching or almost touching the rims, then I squeeze the brake
levers as
> > hard as I can. This serves 2 functions, the first is a safety check
on
> > the cables.
>
> The more important function it serves is to seat the cable head and
> housings into their stops.
>
I file or grind cable housing ends to make sure that cable housings
firmly seat into the furrels so they don't move any further. Cable ends
may seat into upright bar levers but not MTB bars.
> >I've had cable ends come off on several occasions during my
> > tests and this exercise saves me from an unpleasant surprise on the
> > road.
>
> Please tell me what is this unpleasantness.
>
DOH! What happens when you apply the brakes and the cable end breaks
off?
> >The other initially stretches the cables enough so that my brakes
> > are adjust with the right amount of play so that I don't have to
> > readjust the cable length.
>
> Yes, well, "stretches" isn't what most people think. What's going on
is
> compression.
>
I've installed hundreds of brake cables. A new brake cable can stretch a
1/4" or mare and it maintains the length after the lever is released.
> >
> > Chas.
> >
> Robin Hubert
frkr...@gmail.com
* * Chas wrote:
>
> I've installed hundreds of brake cables. A new brake cable can stretch a
> 1/4" or mare and it maintains the length after the lever is released.
I installed a new rear shift cable recently. Bar end friction
shifters, cables under handlebar tape.
The shift lever was all the way in the small cog position, as was the
derailleur. I lubed the cable lightly, ran it through the old (lined)
housing, pulled out all the slack with pliers, and tightened the
derailleur's cable clamp bolt.
Then, bike still on workstand, I cranked and shifted a couple times.
The slack was back. The shifter required maybe ten degrees of motion
before it would move the derailleur.
Did the cable stretch? No way. Shift forces are too light by far.
What was happening was everything in the cable path was settling back
into position. For example, the inner wire was settling into the
shortest path around the complex curves, the cable ends were fully
seating, etc.
It's not stretch.
- Frank Krygowski
Bill Sornson
Or, you're just too weak to pull the cable tight enough in the first place.
HTH <eg>
carl...@comcast.net
Dear Frank,
You apply little force to shifters, but you can apply lots of force to
brake cables.
Chas was talking about brake cables.
As Chalo pointed out, there are 7x7 laid cables with 49 strands that
stretch much more than the more common 1x6x12 laid cables with 19
strands.
The cable stretch calculator that I mentioned is for stretchier 7x7:
http://www.spaceagecontrol.com/calcstre.htm?MA%5B0%5D=50&MA%5B2%5D=60...
or http://tinyurl.com/yxc4m9
Cheers,
Carl Fogel
frkr...@gmail.com
I understand that.
My point is that _apparent_ stretch is present even with lightly loaded
shift cables. This is an indication that people are not typically
perceiving real stretch. They're misinterpreting other effects as
cable stretch.
- Frank Krygowski