Front cantilever brake cable breaks at anchor
#1
Banned.
Thread Starter
Join Date: Sep 2010
Location: Southern "Home-Sweet-Home" California
Posts: 40
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Front cantilever brake cable breaks at anchor
The bike is orig. a Gary Fisher mountain "Advance", but converted to commute/utility bike, as shown ...
I replaced the orig (ca. late 1993) brake cable about 3yrs ago (or roughly 800mi every-third-day commuting), with a SUPPOSED top-grade laminated cable (AZTEC PTFE) + new housing (from Performance Bikes). (The orig. rusted off after a whopping 17 yrs or 6k miles, 3k of which in NW Ohio with snow and salt).
Anyway...
Yesterday, during an emerg. hard stop, the front cable snapped, creating a very dangerous (but fortunately recoverable) situation. It snapped CLEANLY right at the anchor bolt.
It looked like a clean cut (like it was made by a pair of dikes). There was no corrosion (I live in LA, Calif. but several mile from ocean, and store bike inside).
I'm assuming the case (other than manuf. defect) was that the orig centering adjustment -- via yoke, etc.-- wasn't perfect, creating too much movement/shear/strain at the anchor point.
How does one minimize cable stress at the anchor bolt? Are there any commercially avail. strain reliefs, etc., or other tricks?
Thx for any input you can provide!
I replaced the orig (ca. late 1993) brake cable about 3yrs ago (or roughly 800mi every-third-day commuting), with a SUPPOSED top-grade laminated cable (AZTEC PTFE) + new housing (from Performance Bikes). (The orig. rusted off after a whopping 17 yrs or 6k miles, 3k of which in NW Ohio with snow and salt).
Anyway...
Yesterday, during an emerg. hard stop, the front cable snapped, creating a very dangerous (but fortunately recoverable) situation. It snapped CLEANLY right at the anchor bolt.
It looked like a clean cut (like it was made by a pair of dikes). There was no corrosion (I live in LA, Calif. but several mile from ocean, and store bike inside).
I'm assuming the case (other than manuf. defect) was that the orig centering adjustment -- via yoke, etc.-- wasn't perfect, creating too much movement/shear/strain at the anchor point.
How does one minimize cable stress at the anchor bolt? Are there any commercially avail. strain reliefs, etc., or other tricks?
Thx for any input you can provide!
Last edited by hollowman; 10-19-13 at 01:23 AM.
#2
Banned
I think you ask too much from a web forum . is that an actual picture of your brake ,
or did you pull it off the web?
might have had a kink in the cable right there and flexed it once too often ..
just replace the cable earlier , before it fails..
keep an eye out for fraying cables .. Im still using the original transverse Mafac cable
35 years later..
or did you pull it off the web?
might have had a kink in the cable right there and flexed it once too often ..
just replace the cable earlier , before it fails..
keep an eye out for fraying cables .. Im still using the original transverse Mafac cable
35 years later..
Last edited by fietsbob; 10-19-13 at 02:33 AM.
#3
Senior Member
Join Date: Mar 2008
Posts: 8,688
Mentioned: 46 Post(s)
Tagged: 0 Thread(s)
Quoted: 1074 Post(s)
Liked 295 Times
in
222 Posts
It I a bit odd to have such a clean break, but after 3 years of regular use I'd consider it forgiven.
Apart from perhaps checking your clamping torque when you mount the replacement I don't have anything specific to offer.
Apart from perhaps checking your clamping torque when you mount the replacement I don't have anything specific to offer.
#4
Still learning
A brake cable is a $3-$6 part. Don't expect a lifetime of service. Also, if ride it fully loaded with all that luggage over hilly trrrain, it's added strain.
#5
Banned.
Thread Starter
Join Date: Sep 2010
Location: Southern "Home-Sweet-Home" California
Posts: 40
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Speaking of useless remarks ... well, don't feel alone dude ... or OFFENDED by my counter-comments.Because none of the replies thus far has shed any further USEFUL info.
One along the line of ...say ... convert to V-brakes or use a doubled-pulley system to cause them to pull farther (but less hard) than the std. incoming cable pulls.
#6
Senior Member
Join Date: Feb 2004
Location: St Peters, Missouri
Posts: 30,225
Bikes: Catrike 559 I own some others but they don't get ridden very much.
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 1572 Post(s)
Liked 642 Times
in
363 Posts
The part you're looking for is actually called a "link wire". They come in sizes so be sure to measure the one that you have.
__________________
My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.
My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.
#8
Senior Member
Join Date: Sep 2010
Location: Roswell, GA
Posts: 8,319
Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta
Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 1438 Post(s)
Liked 1,091 Times
in
722 Posts
"One along the line of ...say ... convert to V-brakes..." I do not see any reason why, after 17 years' service, you would feel a need to replace your brakes with another kind. The ones you have are time-proven by you and countless others.
My recommendation would be to lose the link wire (which I find difficult to adjust) and go with a straddle cable/carrier system. I especially like the Problem Solvers Wide Cable Carrier https://problemsolversbike.com/produc..._cable_carrier
and the DIA-COMPE E-Z-R Braided Straddle Cable. The cable is 2mm diameter which is significantly thicker than most, and it has a nice little handle to ease removing it from the hooked end of the brake.
My recommendation would be to lose the link wire (which I find difficult to adjust) and go with a straddle cable/carrier system. I especially like the Problem Solvers Wide Cable Carrier https://problemsolversbike.com/produc..._cable_carrier
and the DIA-COMPE E-Z-R Braided Straddle Cable. The cable is 2mm diameter which is significantly thicker than most, and it has a nice little handle to ease removing it from the hooked end of the brake.
#9
Senior Member
Join Date: Feb 2004
Location: St Peters, Missouri
Posts: 30,225
Bikes: Catrike 559 I own some others but they don't get ridden very much.
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 1572 Post(s)
Liked 642 Times
in
363 Posts
I'm going to disagree with my friend, dsbrantjr, about which is easier to adjust. I'd stick with the link wire.
__________________
My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.
My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.
#10
Senior Member
LOL!! "Too much to ask" ?? Really, dude? I mean you've made 29,906 posts since a only few mos. before my Join Date. I thought with such a YAPPING record , you'd be the last type to make a remark like that?
Speaking of useless remarks ... well, don't feel alone dude ... or OFFENDED by my counter-comments.Because none of the replies thus far has shed any further USEFUL info.
One along the line of ...say ... convert to V-brakes or use a doubled-pulley system to cause them to pull farther (but less hard) than the std. incoming cable pulls.
Speaking of useless remarks ... well, don't feel alone dude ... or OFFENDED by my counter-comments.Because none of the replies thus far has shed any further USEFUL info.
One along the line of ...say ... convert to V-brakes or use a doubled-pulley system to cause them to pull farther (but less hard) than the std. incoming cable pulls.
#11
Banned.
Thread Starter
Join Date: Sep 2010
Location: Southern "Home-Sweet-Home" California
Posts: 40
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
My recommendation would be to lose the link wire (which I find difficult to adjust) and go with a straddle cable/carrier system. I especially like the Problem Solvers Wide Cable Carrier https://problemsolversbike.com/produc..._cable_carrier
and the DIA-COMPE E-Z-R Braided Straddle Cable. The cable is 2mm diameter which is significantly thicker than most, and it has a nice little handle to ease removing it from the hooked end of the brake.
and the DIA-COMPE E-Z-R Braided Straddle Cable. The cable is 2mm diameter which is significantly thicker than most, and it has a nice little handle to ease removing it from the hooked end of the brake.
...so if I can find an anchor bolt/clamp that pivots (turns), that'd work, too.
Last edited by hollowman; 10-19-13 at 08:20 AM.
#12
Mad bike riding scientist
Join Date: Nov 2004
Location: Denver, CO
Posts: 27,250
Bikes: Some silver ones, a red one, a black and orange one, and a few titanium ones
Mentioned: 149 Post(s)
Tagged: 1 Thread(s)
Quoted: 6133 Post(s)
Liked 4,067 Times
in
2,310 Posts
I suspect your problem is that you are tightening the anchor too tightly. Although I hate the Shimano link wire system, I've not seen problems with it putting too much stress on the cable itself. You could also be experiencing corrosion and salt cracking due to your proximity to the ocean. This would be worse with a mild steel...i.e. cheap...cable than with a stainless steel cable.
Replace the cable with a stainless one and watch it.
Replace the cable with a stainless one and watch it.
__________________
Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
#13
Senior Member
Join Date: Jan 2013
Location: Llano Estacado
Posts: 3,702
Bikes: old clunker
Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 684 Post(s)
Likes: 0
Liked 104 Times
in
82 Posts
Someone once wrote "Methinks the lady doth protest too much."
Normally, that part of the cable experiences very little flex. Since your photos don't show your actual brake, I suspect a non standard installation and/or something fouling the cable. [Cue protests.]
Normally, that part of the cable experiences very little flex. Since your photos don't show your actual brake, I suspect a non standard installation and/or something fouling the cable. [Cue protests.]
#15
Banned
Blind guessing can be an amusement for the guesser.. + I can do this and drink .
and listen to the more educational things I can find over the web at the same time..
and listen to the more educational things I can find over the web at the same time..
#16
Banned.
Thread Starter
Join Date: Sep 2010
Location: Southern "Home-Sweet-Home" California
Posts: 40
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
#17
Banned.
Thread Starter
Join Date: Sep 2010
Location: Southern "Home-Sweet-Home" California
Posts: 40
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I suspect your problem is that you are tightening the anchor too tightly. Although I hate the Shimano link wire system, I've not seen problems with it putting too much stress on the cable itself. You could also be experiencing corrosion and salt cracking due to your proximity to the ocean. This would be worse with a mild steel...i.e. cheap...cable than with a stainless steel cable.
Replace the cable with a stainless one and watch it.
Replace the cable with a stainless one and watch it.
#18
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,504
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 139 Post(s)
Tagged: 1 Thread(s)
Quoted: 5680 Post(s)
Liked 2,386 Times
in
1,320 Posts
Brake and gear cables break for the same reason as spokes --- Metal fatigue.
Every time you apply your brake the angle of the cable to the arm changes slightly, causing it to bend back and forth where it meets the pinch bolts. It's the same as when you bend a paper clip back and forth until it hardens, then fatigues and breaks. Cables have a useful life after which they need to be replaced before fatigue kills them. All cables that move suffer this, including elevator cables, and I replace my elevator cables on a legally mandated schedule, at a cost of over $5K per shot.
The problem with your canti cable is compounded by modern quality cable construction and the link system.
Today's better brake cables are die drawn to make the outside smoother so there's less friction in the housing. That's good, but the process also makes them less supple and more prone to fatigue. The levers are carefully designed to avoid flex at the head, but using the link system brings that die drawn wire down to the bolt where it gets bent back and forth. I prefer a traditional cable carrier where the main cable ends at the carrier and a separate straddle cable is used. That allows the straddle to be heavier, and not die drawn so it has more fatigue resistance.
If you want to increase the cable life you can slide it into about 3/4" of stainless tubing (model airplane fuel line) And trap that under the pinch bolt with about 1/4" sticking out on the business end. That acts like the reinforcement on many electrical cords to spread the flex out over some distance and prevent breakage.
I do this for a piece of machinery where cable replacement is a PIA, but don't bother for my bikes because the housing life tends to be shorter than the wire's life and I simply replace everything every few years based on housing friction.
Every time you apply your brake the angle of the cable to the arm changes slightly, causing it to bend back and forth where it meets the pinch bolts. It's the same as when you bend a paper clip back and forth until it hardens, then fatigues and breaks. Cables have a useful life after which they need to be replaced before fatigue kills them. All cables that move suffer this, including elevator cables, and I replace my elevator cables on a legally mandated schedule, at a cost of over $5K per shot.
The problem with your canti cable is compounded by modern quality cable construction and the link system.
Today's better brake cables are die drawn to make the outside smoother so there's less friction in the housing. That's good, but the process also makes them less supple and more prone to fatigue. The levers are carefully designed to avoid flex at the head, but using the link system brings that die drawn wire down to the bolt where it gets bent back and forth. I prefer a traditional cable carrier where the main cable ends at the carrier and a separate straddle cable is used. That allows the straddle to be heavier, and not die drawn so it has more fatigue resistance.
If you want to increase the cable life you can slide it into about 3/4" of stainless tubing (model airplane fuel line) And trap that under the pinch bolt with about 1/4" sticking out on the business end. That acts like the reinforcement on many electrical cords to spread the flex out over some distance and prevent breakage.
I do this for a piece of machinery where cable replacement is a PIA, but don't bother for my bikes because the housing life tends to be shorter than the wire's life and I simply replace everything every few years based on housing friction.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
Last edited by FBinNY; 10-19-13 at 04:34 PM.
#19
Mad bike riding scientist
Join Date: Nov 2004
Location: Denver, CO
Posts: 27,250
Bikes: Some silver ones, a red one, a black and orange one, and a few titanium ones
Mentioned: 149 Post(s)
Tagged: 1 Thread(s)
Quoted: 6133 Post(s)
Liked 4,067 Times
in
2,310 Posts
Chloride cracking doesn't necessarily result in discoloration of stainless. The compounds formed are water soluble chlorides of iron and chromium. The chloride salts are yellow and green, respectively. They get flushed away and may not result in the formation of iron oxides that are red in color.
__________________
Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
#20
Banned.
Thread Starter
Join Date: Sep 2010
Location: Southern "Home-Sweet-Home" California
Posts: 40
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Some images of the genuine article at bottom ... (Note + ATTN. Aztec, other cable manufs. ! These images and descriptions are GRAPHIC and damning. Hence, in the future, you could get sued ... so address the problem or have well-paid lawyers! Too bad bike manuf's are not STRICTLY govt. regulated like automotive (NBSN is a joke!), or NHTSA would have a product-recall field day. They love this kinda stuff !! )
NOTE: The rust on some components -- none on cable, as clearly absent in the first photo -- is over 10 years old (from my Ohio days, but has not "grown" since my move to SoCal).
IAC ...I did manage to re-use the same AZTEC PTFE cable, but the slack is now real slim ... i.e., just barely clearing the clamp.
FBinNY ... yes, I DIY in electronics/electrical and use strain reliefs often. Like you, those came almost immediately to mind after this incident. (I still have to install them after finding and fashioning some steel sheeting).
Another thing I did was adjust (minimize) the cable deflection/movement (at anchor clamp) to as little as possible, by "tightening up" gaps/tolerances. Hence minimizing the metal fatigue (paper clip effect).
Didn't know how cable manuf. had changed -- so, if as you describe, I'll have to either find the PROPER cable or find it good+used or NOS (new-old stock) on eBay, etc.
NOTE: The rust on some components -- none on cable, as clearly absent in the first photo -- is over 10 years old (from my Ohio days, but has not "grown" since my move to SoCal).
IAC ...I did manage to re-use the same AZTEC PTFE cable, but the slack is now real slim ... i.e., just barely clearing the clamp.
FBinNY ... yes, I DIY in electronics/electrical and use strain reliefs often. Like you, those came almost immediately to mind after this incident. (I still have to install them after finding and fashioning some steel sheeting).
Another thing I did was adjust (minimize) the cable deflection/movement (at anchor clamp) to as little as possible, by "tightening up" gaps/tolerances. Hence minimizing the metal fatigue (paper clip effect).
Didn't know how cable manuf. had changed -- so, if as you describe, I'll have to either find the PROPER cable or find it good+used or NOS (new-old stock) on eBay, etc.
Last edited by hollowman; 10-25-13 at 07:15 PM.
#21
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,504
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 139 Post(s)
Tagged: 1 Thread(s)
Quoted: 5680 Post(s)
Liked 2,386 Times
in
1,320 Posts
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
Last edited by FBinNY; 10-25-13 at 07:06 PM.
#22
Senior Member
Join Date: Jan 2013
Location: Llano Estacado
Posts: 3,702
Bikes: old clunker
Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 684 Post(s)
Likes: 0
Liked 104 Times
in
82 Posts
Some images of the genuine article at bottom ... (Note + ATTN. Aztec, other cable manufs. ! These images and descriptions are GRAPHIC and damning. Hence, in the future, you could get sued ... so address the problem or have well-paid lawyers! Too bad bike manuf's are not STRICTLY govt. regulated like automotive (NBSN is a joke!), or NHTSA would have a product-recall field day. They love this kinda stuff !! ) . . .
#24
Banned.
Thread Starter
Join Date: Sep 2010
Location: Southern "Home-Sweet-Home" California
Posts: 40
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Of course. Can't pass one up on you, huh? Darn!
Yeah ... it's all about under-the-table rewards (usually precious metals), better housing units in the tower blocks, etc. for only a few common-citizen-based sentences and easily-engineered photos, in their topical milieu ... IOW, this thread any my posted photos
Yeah ... it's all about under-the-table rewards (usually precious metals), better housing units in the tower blocks, etc. for only a few common-citizen-based sentences and easily-engineered photos, in their topical milieu ... IOW, this thread any my posted photos
#25
Banned.
Thread Starter
Join Date: Sep 2010
Location: Southern "Home-Sweet-Home" California
Posts: 40
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Looking at what's readily available, this 3/32" copper tube may be the best bet for stain relief. But as I said, switching from the link which runs the main cable to the anchor, to the traditional system where the main cables ends at the yoke cable carrier, and a more flexible cable is used for the yoke, gives you the benefit od die drawn cable for low friction, with the better fatigue resistance on the yoke cable.