Bicycle Mechanics - Brake cable just broke while riding

My brake cable just broke as I was riding today, when I pulled rather hard on it, just as a test. Good thing I tested! The cable end (which attaches to the brake lever) was apparently being slowly broken off of the rest of the cable, and it just snapped. I put a new cable on and I'd like to know how I can prevent this in the future, or is it a fact of life? It wasn't rusted or anything...

I had to ride home with my back brakes only, and as you all know, those are not nearly as strong.

or is it a fact of life?

You nailed it there.

How old are the cables? Aslo, if one snapped then you should check all the cables including the ones on the shifter cables.

If they are old, you should not only replace the cables but the housing as well. It also makes a diferance if you fork out the extra few duckets for the coated cables and housing. Longer life and smoother action.

:beer: :beer:

Your cables must have been very old. I would also check your housings, as dirtbikedude suggested. It sounds as though your cables became so frayed at the pinch bolt that there finally wasn't enough strength left in the cable to stay in the pinch bolt.

-Moab

No, not at the pinch bolt, at the cable end which attaches to the brake lever. That's why I didn't have any idea it would happen - that part of the cable is not visible, in general. My gear cable already broke, so I don't have to worry about that breaking for a while. If I had taken my bike in for a regular "check-up" or tune-up or whatever you call it, just prior to the cable breaking, would they have discovered it was about to break and fix it for me, or do you think they wouldn't have checked that extensively?

If you had your bike in for a tune-up if probably wouldnt have been noticed. A good shop will apply the brakes with lots of pressure to make sure everything is tight. Aside from that I it wouldnt have been caught unless the fraying was excessive.

Joelr indirectly raises an interesting question: how often should one replace one's brake cables as preventive maintenance? Having snapped a cable once under very similar circumstances, I now periodically release the brake calilpers, squeeze the handles, and look inside for any shred of evidence of fraying. I no longer reuse cables, as I sometimes did in my starving student days, but I now buy a new control cable whenever I remove and replace or do major work on a brake or derailleur.

that's pretty scary dude... what do you do when this happens on a long steep descent??

then again, you're pretty unlikely to lose BOTH brakes at the same time.

Yes, unlikely to lose both brakes (unless the cables are both in the same shape, which I suppose isn't that uncommon), but very likely to lose your best brake, and have only a pathetic rear brake left to barely slow your descent. You'll be fine as long as you never go too fast to stop with your rear break if need be. Somehow I doubt that is uppermost on most bikers' minds, though. Now a question: is it good maintenance to oil one's exposed break cable every now and then to ensure protection from rust? If not, why not?

Also, and maybe this belongs in a separate thread - what is WD40 exactly? The bottle says it does anything you want it to - frees rusted parts, cleans off dirt, oil, water, lubricates hinges, screws and anything else, and is great for lubing chains. However, everyone else tells me WD40 is NOT an oil, it is a solvent (but it does come from petroleum, right? Isn't petroleum an oil?), and therefore it should only be used to clean oil off of things, or dissolve rust, but not as a lubricant. So what's the truth, and can it be explained in a sensical manner?

Now a question: is it good maintenance to oil one's exposed break cable every now and then to ensure protection from rust? If not, why not?

the cables are made of a rust proof/stainless steal type of metal. at least the ones I use are. in 20 plus years of riding I have never had a cable rust up on me. and I live in the pacific NW so there's lots of water around.

Oil or grease is indeed a godd way to lubricate cables. I don't see it that much for rust prevention as I see it as a way to improve free movement, especially in a bike used year round.

Regarding preventative maintenance, I never replace cables unless they brake. However, I inspect them yearly or twice yearly. On cantis or v-brakes, just release the cable tension (by "unhooking" the cable from the brake arm) and slide the cable as much as you can. Look also in the brake lever to see what the cable looks like. Replace frayed cables ASAP.

Regards,

[
Also, and maybe this belongs in a separate thread - what is WD40 exactly? The bottle says it does anything you want it to - frees rusted parts, cleans off dirt, oil, water, lubricates hinges, screws and anything else, and is great for lubing chains. However, everyone else tells me WD40 is NOT an oil, it is a solvent (but it does come from petroleum, right? Isn't petroleum an oil?), and therefore it should only be used to clean oil off of things, or dissolve rust, but not as a lubricant. So what's the truth, and can it be explained in a sensical manner? [/B]

It is mostly parafin, thats why it gets in so easily. If it can get in easily, it wont stay long either :)

:D

White teflon bearing grease works well on brake cables. When installing a new cable, coat it with grease before sliding it into the housing.

Anything that doesn't attract dirt.
Pull the cables apart from time to time and clean.

Originally posted by John E
Joelr indirectly raises an interesting question: how often should one replace one's brake cables as preventive maintenance?

According to Bicycling Mag they recommend replacing cable and housing for brakes and shifters once a year.

Say it with me: Teflon coated cables GOOOOOOOD

Found this thread with interest. I too suffer too many broken cables. The fray at the brake end where they are clamped. I have indeed even lost both cables at once on the one hill. And yes, this is scary stuff. I asked round, as to what's causing it. Noone knows. I've been riding since I was a kid, and for a long time as an adult in many different places and cities, commuting a lot of the time, and in all those years, never ever broke a single cable in this manner.

Suddenly, I bring my bike to Hobart (Tasmania) and in short order one breaks. It's frayed at the clamp. And of coure it breakes when braking hard downhill. MY read brake saved me. Hobart is hilly. Worse still one of my daily rides commuting involves a very steep hill which goes down fro 1km and ends at a traffic light on a main road. I do not want to reach this light out of control, nor do I wat to glide down the hill at a walking pace out of parnoid fear.

I've replace dthe cables, both of them several times now for this reason, and aagain, I did some maintenace just this weekend and notice BOTH the dange brake cables are fraying at the clamp.

What could be causing this?

My first thought was overtightening, but I don't think I am, I'm not doing anything I haven't done before (to my knowledge - but maybe I got stornger as I got older ;-). Then I though maybe hard edges on the clamps, so I filed the back just a smidgeon, to round of the corners. But no luck.

This happens more than once a year and checking them once per annum would be risky. What puzzles me is why? What's going on.

Is the that Hobart is simply more hilly and more demaning on brakes than anywhere else I've ridden over teh last 30 years? Or is it that I am unknowingly overtightening the clamps, and if so how hard should I tighten them? I already posted on another thread that "hard enough to hold the cable" isn't really useful feedback unless I have a test for that criterion (I don't want to find out at the bottom of the hill that it wasn't and my cable just pulls through the clamp!).

Frankly, it has me bamboozled.

your cables must have been eitehr somehow abused or very old. Sometimes little things can break one thread of the cable which can fray and eventually more and more threads break until thers only a few left and frankly that isnt enough to deal with brake force. Theres the replace cable once a year thing but i think that if you check it over and clean them out its all good. but teflon works wonders :)

Well, maybe the first ones that broke after I migrated me and my bike to Hobart were old. In fact yes, they were old, I know that because I'd never broken a cable before and hadn't repalced them since I bought the bike, which was a good many years before.

But it's happened again and again and again with cables that definitely aren't old, because I've bought them. I've even asked every bike shop I could for advice, on cables, do they make like mega cables, am I like using wimpy cables or what?

What's the teflon story? isn't that a substance used to lubricate, rather than strengthen?

Found this thread with interest. I too suffer too many broken cables. The fray at the brake end where they are clamped. I have indeed even lost both cables at once on the one hill. And yes, this is scary stuff. I asked round, as to what's causing it. Noone knows. I've been riding since I was a kid, and for a long time as an adult in many different places and cities, commuting a lot of the time, and in all those years, never ever broke a single cable in this manner.

Suddenly, I bring my bike to Hobart (Tasmania) and in short order one breaks. It's frayed at the clamp. And of coure it breakes when braking hard downhill. MY read brake saved me. Hobart is hilly. Worse still one of my daily rides commuting involves a very steep hill which goes down fro 1km and ends at a traffic light on a main road. I do not want to reach this light out of control, nor do I wat to glide down the hill at a walking pace out of parnoid fear.

I've replace dthe cables, both of them several times now for this reason, and aagain, I did some maintenace just this weekend and notice BOTH the dange brake cables are fraying at the clamp.

What could be causing this?

My first thought was overtightening, but I don't think I am, I'm not doing anything I haven't done before (to my knowledge - but maybe I got stornger as I got older ;-). Then I though maybe hard edges on the clamps, so I filed the back just a smidgeon, to round of the corners. But no luck.

This happens more than once a year and checking them once per annum would be risky. What puzzles me is why? What's going on.

Is the that Hobart is simply more hilly and more demaning on brakes than anywhere else I've ridden over teh last 30 years? Or is it that I am unknowingly overtightening the clamps, and if so how hard should I tighten them? I already posted on another thread that "hard enough to hold the cable" isn't really useful feedback unless I have a test for that criterion (I don't want to find out at the bottom of the hill that it wasn't and my cable just pulls through the clamp!).

Frankly, it has me bamboozled.
If your cables are fraying at the clamp, the clamp is usually too tight. If you overtighten the clamp it spreads the cable out, reducing it from a cable to individual pieces of wire, which will individually break until that last pull on the cable, then the rest comes apart. A less likely (though possible) cause is improper installation or improper clamp positioning.

If you are able, go to a bike shop and look closely at the brakes on some good, high-end bikes. You won't see the cables frayed on those. Two reasons, good cables (which are not expensive) and proper installation and tightening. I would bet that the folks at the shop would aid you in your quest for knowledge you need on how to do this.

"Hard enough" means just that. Tight enough so the cable doesn't come loose when the brake levers are used, but not so tight your cable is smooshed. If you're not handy to a shop, a trial-and-error session with your brakes and cables may work for you.

A good brake cable is EXTREMELY strong. I think they would be impossible to break with just the force of the brake lever.

Sounds like the guy who wanted 3 breaks on his bike, 2 up front and one rear had a point. There was a thread a few weeks ago about it, and it caused a bit of an argument (I believe it was locked in the end). Suppose he has a point though...

According to Bicycling Mag they recommend replacing cable and housing for brakes and shifters once a year.

Bicycling Magazine recommends replacing you whole bike at least once per year :D

Thanks for the tips. Alas the biks shops I visited were all unable to advise, to my surprise and chagrin.

hard enough is still a bit nebulous for me, but on anothe rtrhead I was pointed to:

http://www.parktool.com/repair_help/torque.shtml

which is great. I'm sure I can brorow a torque wrench somewhere and then get a good feel for how much torque is right. This web page is exactly the kind of objective approach I was hoping existed.

that's pretty scary dude... what do you do when this happens on a long steep descent??



use your feet!

My brake cable just broke as I was riding today, when I pulled rather hard on it, just as a test. Good thing I tested! The cable end (which attaches to the brake lever) was apparently being slowly broken off of the rest of the cable, and it just snapped. I put a new cable on and I'd like to know how I can prevent this in the future, or is it a fact of life? It wasn't rusted or anything...

I had to ride home with my back brakes only, and as you all know, those are not nearly as strong.

When you install a new cable, put a tiny dab of grease where the cable end meets the cable to make it slide better and minimize fraying.

Indeed, it is scary and yes, the only option is to use your feet. If things got really bad you might have to bail ... but I've not encountered that. Fortunately I've had several brakes on steep downhills like this, and once even both damned cables at once, but always (count my lucky stars) just before coming to a stop - that is, my feet worked just fine, and the brakes lasted the till the last moment!

This may or may not be wild coincidence and good fortune though. It might well be that we (I) apply brake pressure iincreasingly squeezing hardest at toward the end of the slow down.

Sounds like the guy who wanted 3 breaks on his bike, 2 up front and one rear had a point. There was a thread a few weeks ago about it, and it caused a bit of an argument (I believe it was locked in the end). Suppose he has a point though...

That was me. And I asked to have it locked, because it had got out of hand...

I just hate single-point failures. That's why I will never fly in a helicopter...
I live by the principle: better safe than sorry! :)

Want to point us to the thread - could be fun to read :)

Thanks for the tips. Alas the biks shops I visited were all unable to advise, to my surprise and chagrin.

hard enough is still a bit nebulous for me, but on anothe rtrhead I was pointed to:

http://www.parktool.com/repair_help/torque.shtml

which is great. I'm sure I can brorow a torque wrench somewhere and then get a good feel for how much torque is right. This web page is exactly the kind of objective approach I was hoping existed.
"Hard enough" is a little tough to quantify. Some cable clamps, Shimano for example, are grooved so when the clamp is tight the cable won't be deformed. On other clamps, particularly cheaper ones, the clamping faces are flat, and the cable gets flattened as the clamp is tightened.

That's a good point and I'll look at it. Of course, every peice of bike equipment I've ever seen or knowing owned had Shimano written on, so I was planning to use the Shimano figures on that table ... I don't think I ever seen a market so dominated by one player as bikes by Shimano (and operating systems by Microsoft I guess ;-). But then perhaps that reflects my exposure to the market more than the market itself (mainly here in parts of Australia and in a few parts of Europe).