Author Topic: Braking accidents /malfunctions  (Read 2236 times)

ourclarioncall

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Braking accidents /malfunctions
« on: December 16, 2021, 12:30:48 am »
Just wondering which type of brakes are least likely to fail?

Or safest if they do somehow fail

And has anyone ever had a scare or accident while riding with brakes locking or something similar ?

JohnR

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Re: Braking accidents /malfunctions
« Reply #1 on: December 17, 2021, 08:25:08 am »
Rim brakes often gave me scary moments due to insufficient braking capacity when the rims were wet or dirty. Then I got a bike with disc brakes and discovered the joy of reliable all-weather braking ability with the overall stopping ability being controlled by the grip of tyre on road surface. Disc brakes also eliminate the long term risk of the rims wearing away and exploding while they aren't troubled by a bent rim.

I don't recall having failure of a brake mechanism. Any type of brake needs regular checks and adjustment and the clearances / movement of a disc brake mechanism are smaller than on rim brakes. Cable failure is the most likely cause of brake failure whatever the type of brake. Hydraulic brakes are nice due to lack of friction but have their downsides of less easy maintenance and the risk that any moisture in the fluid can boil under extreme braking conditions which will result in the brake locking on.

Disc brake pads come in many shapes and sizes so, if travelling far from home then it's advisable to carry some spares. They don't take up significant room in the baggage. The one disadvantage of a disc brake on the front wheel is that stiffer forks are needed to handle the torque caused by the brake when in use which is why you see some Thorn bikes with a rim brake on the front and a disc brake on the back. Personally, I'm happy to accept a slightly worse rise quality as a trade off for getting better braking ability given that deceleration results in weight transfer onto the front wheel, particularly if going downhill.

B cereus

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Re: Braking accidents /malfunctions
« Reply #2 on: December 18, 2021, 09:07:50 am »
Total brake failures are thankfully quite rare and the risks can be further reduced by proper maintenance. Your best insurance is the legal requirement for bicycles to have two independent brakes.

It may not be a fashionable choice, but for reliability and consistency in both wet and dry conditions, and minimal maintenance, I'd nominate the humble drum brake.

ourclarioncall

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Re: Braking accidents /malfunctions
« Reply #3 on: December 18, 2021, 01:57:30 pm »
Total brake failures are thankfully quite rare and the risks can be further reduced by proper maintenance. Your best insurance is the legal requirement for bicycles to have two independent brakes.

It may not be a fashionable choice, but for reliability and consistency in both wet and dry conditions, and minimal maintenance, I'd nominate the humble drum brake.

Do you get drum brakes for modern touring bikes ?

Cheers

ourclarioncall

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Re: Braking accidents /malfunctions
« Reply #4 on: December 18, 2021, 02:09:10 pm »
Rim brakes often gave me scary moments due to insufficient braking capacity when the rims were wet or dirty. Then I got a bike with disc brakes and discovered the joy of reliable all-weather braking ability with the overall stopping ability being controlled by the grip of tyre on road surface. Disc brakes also eliminate the long term risk of the rims wearing away and exploding while they aren't troubled by a bent rim.

I don't recall having failure of a brake mechanism. Any type of brake needs regular checks and adjustment and the clearances / movement of a disc brake mechanism are smaller than on rim brakes. Cable failure is the most likely cause of brake failure whatever the type of brake. Hydraulic brakes are nice due to lack of friction but have their downsides of less easy maintenance and the risk that any moisture in the fluid can boil under extreme braking conditions which will result in the brake locking on.

Disc brake pads come in many shapes and sizes so, if travelling far from home then it's advisable to carry some spares. They don't take up significant room in the baggage. The one disadvantage of a disc brake on the front wheel is that stiffer forks are needed to handle the torque caused by the brake when in use which is why you see some Thorn bikes with a rim brake on the front and a disc brake on the back. Personally, I'm happy to accept a slightly worse rise quality as a trade off for getting better braking ability given that deceleration results in weight transfer onto the front wheel, particularly if going downhill.

Thanks

So when going downhill with a heavy load, what brake or brakes am I supposed to be using ? Im a rear brake user and it wasn’t until coming on this forum that I learned I’m supposed to be using the front most of the time

Also I hear people saying things like they wore out their disc brakes going downhill. What’s the scoop with that ? To do with the quality of the pads or the braking skills of the person

And when going downhill (which could have you build up to high speeds like 40+ mph, is it advisable to bring your speed down to a certain amount or safe range such as 10-20mph ?

On the fork choice, an eBay thorn bike seller said he had the disc fork previously and said his hands went numb within half an hour and didn’t like it at all so had the more comfortable rim break instead . But you reckon it’s maybe not that bad ? Whether he was being literal or not I’m not sure (as in the numb after 30 mins )

John Saxby

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Re: Braking accidents /malfunctions
« Reply #5 on: December 18, 2021, 03:11:34 pm »
I've not had a brake failure - yet.

My guidelines from long practical experience:

I very rarely go down a hill flat-out, mainly 'cos in the hilly country where I live, the smooth roads have turns in them, with trees and cliffs on either side so that you can't see around the curves until you're in them. And on the more common patchy/bumpy ones, one uses a much more deliberate approach or pays the consequences.

On my monthlong tour through the Rockies & Cascadia a few years ago, I met some long, smooth and steep descents.  My Raven was fully loaded, and I had rim brakes, which I'd fitted with new Koolstop Salmon pads. (I carried spares as well, but didn't need them.)  Everything worked well with no worries, even in a rainy descent from Sunwapta Pass on the Icefields Parkway. 

On the long descents, I firmly-feathered the front brake, partly because there was wildlife around, partly to stay within sensible limits in case of frost heaves.  Once, on the descent from Mt Logan in Montana, I stopped for a photo op, and that let things cool down. (Tho' I didn't check the rim to see if it was necessary.)

40 mph?  Not for me.  The only time I've ever done that was some 15-plus years ago on a straight downhill, maybe 400 metres, entering a small town in Kwa-Zulu Natal, on my light-touring & unloaded derailleur bike.  It was late-afternoon so  the clear and empty road before us was well-lighted by the sun behind us.  Problem was -- there was a roundabout just beyond the bottom of the descent, not visible from the hilltop. We stopped in time - unloaded bikes, gear in the support van. :(  I said to my mate, "Let's not do that again, eh?"  He had the speedo, and we had touched 65 km/h.

Safe downhills! ;)
« Last Edit: December 18, 2021, 03:14:48 pm by John Saxby »

JohnR

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Re: Braking accidents /malfunctions
« Reply #6 on: December 18, 2021, 04:55:58 pm »
Also I hear people saying things like they wore out their disc brakes going downhill. What’s the scoop with that ? To do with the quality of the pads or the braking skills of the person
Brake pads do wear out. How quickly depends on the pad material and the need to use the brakes (see below). If energy has to be dissipated I don't think there's a significant difference in pad wear between prolonged gentle braking and shorter heavier braking.

And when going downhill (which could have you build up to high speeds like 40+ mph, is it advisable to bring your speed down to a certain amount or safe range such as 10-20mph ?
A lot depends on familiarity with the road. If it's a wide road, free of potential obstacles and you can see well beyond the bottom of the hill then you can go as fast as gravity and your nerves will let you (from time to time consider the consequences of an unforeseen mishap but the energy to be dissipated is proportional to the square of the speed). If, on the other hand, you can't see very far ahead and/or it's a single track road where an oncoming vehicle might appear at any time then you need to proceed with caution (even more so if the surface is wet or dirty) so that you can safely stop should an obstacle appear. What stopping distance you need to allow depends on your confidence in the brakes as well as the load you need to bring to a halt. On any significant downhill I always have my fingers ready on the brake levers to minimise the reaction delay.

On the fork choice, an eBay thorn bike seller said he had the disc fork previously and said his hands went numb within half an hour and didn’t like it at all so had the more comfortable rim break instead . But you reckon it’s maybe not that bad ? Whether he was being literal or not I’m not sure (as in the numb after 30 mins )
It's not a problem I've encountered but any vibration from the road surface is more likely to be transferred if the tyres are rock hard. They are the primary suspension and my tyre pressures are set for comfort. In addition I use Ergon grips on my handlebars plus gloves / mitts with some gel padding.

Ability to stop is arguably more important than ability to go and brakes usually gradually deteriorate rather than suddenly fail so any deterioration in braking ability needs investigation. 

PH

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Re: Braking accidents /malfunctions
« Reply #7 on: December 18, 2021, 11:05:49 pm »
Well maintained brakes don't fail often and when they do it's usually gradual rather than sudden.  Accident damage is far more likely, there's plenty of sticking out bits and exposed delicate parts on all systems.  If you're going somewhere remote, then the ability to fix it at the roadside is a bonus.  If you're not straying too far from the land of bike shops, it doesn't really matter, swapping out a complete brake is a minor job, regardless of the type. Maintenance wise, hydraulic discs are IMO the easiest to live with.
In extreme cases misuse can cause problems, overheating is the major one, it can boil hydraulic fluid, glaze the pads on any disc brake and overheating rims can lead to the blocks depositing on the rim without it doing much slowing or in really extreme circumstances getting so hot it blows a tube.  All of which I've heard of, none of which I've experienced. Best way not to overheat the brakes on a long downhill is to use intermittently rather then dragging.
But knowing your brakes, knowing your bike, should lead to riding within it and your capabilities. When i have had to make an unexpected sudden stop, whether my error or some unforeseen circumstance, my experience is it's traction rather than braking that will let you down first (Sometimes literally)

Forks designed for rim brakes can be less rigid than disc forks, though it doesn't necessarily follow that they are. How much that matters, depends on the bike, the fork, the tyres (Size and pressure) and mostly the riders perceptions and sensitivity.

martinf

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Re: Braking accidents /malfunctions
« Reply #8 on: December 19, 2021, 08:17:17 am »
Well maintained brakes don't fail often and when they do it's usually gradual rather than sudden.

In extreme cases misuse can cause problems, overheating is the major one, it can boil hydraulic fluid, glaze the pads on any disc brake and overheating rims can lead to the blocks depositing on the rim without it doing much slowing or in really extreme circumstances getting so hot it blows a tube.  All of which I've heard of, none of which I've experienced. Best way not to overheat the brakes on a long downhill is to use intermittently rather then dragging.

Apat from insufficient braking power when I experimented with steel rims, I have had two brake-related failures in over 266,000 kms of riding. Both occurred in the 1970's :

- a brake centre bolt on a sidepull brake snapping on a long, steep and twisty descent in Yorkshire. I managed to stop on the other brake. A few kms further on we managed to find a retired cycle mechanic who jury-rigged the brake with a bolt so that I could continue the tour with two brakes.
- a front tyre blowoff due to using cheap tyres and continuous braking on a long, steep and twisty descent on the edge of Dartmoor.

Since the latter incident, I am careful on long descents. If I judge it neccessary I stop and wait for the rims to cool down. Dunking the rims in a puddle can speed up cooling if riding in wet weather. Other brakes are vulnerable to overheating. I haven't had disc brakes on a bicycle, but have tested coaster, drum and roller brakes on steep descents, they all get very hot if used continuously.

my experience is it's traction rather than braking that will let you down first (Sometimes literally)

On all my bikes I can lock the rear wheel, even with water on the rims, even with the calliper brakes on my Bromptons. The latter aren't so effective as the V-brakes and cantilevers on my large-wheel bikes but as the 16" tyres also have less grip they are sufficient.

I don't try to lock the front wheel.

So I haven't bothered going to discs and have mainly cantilever and V-brakes,  with one visitor bike fitted with a roller brake on the rear, which works but which I don't like (it has a harsh feel, needs a special grease and is a bit messy) and another visitor bike fitted with a rear drum brake, which I do like (virtually no maintenance).

All the rim brakes I have used need to be maintained to ensure they continue to give good performance - periodic cable replacement, good replacement brake pads, and for the calliper brakes periodic overhauls to regrease the mechanism and adjust play (this is less necessary with V and cantilever brakes).

Used on the rear, other types of brake (coaster, drum and roller) have the advantage of not spraying muck and water onto the chain, which is no longer an issue for me on most bikes as I use Chaingliders where possible.


Moronic

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Re: Braking accidents /malfunctions
« Reply #9 on: December 19, 2021, 12:17:43 pm »

So when going downhill with a heavy load, what brake or brakes am I supposed to be using ? Im a rear brake user and it wasn’t until coming on this forum that I learned I’m supposed to be using the front most of the time.

The best brake IMO is the air brake. Sit up at soeed and your body and the bike will create a partial vaccum behind them that arrests your progress. I always try to rely on this as much as possible. Vehicle brakes in general, and bicycle brakes in particular, are not designed to be applied for extended periods, such as constantly on long descents.

 If you do need to brake, the rear brake will be the first to skid the tyre but until it skids the tyre it is just as effective as the front. If you need to brake hard, the front brake is the only one that will meet your need.


Also I hear people saying things like they wore out their disc brakes going downhill. What’s the scoop with that ? To do with the quality of the pads or the braking skills of the person.

Could be anything but anything includes braking skills. See above.

And when going downhill (which could have you build up to high speeds like 40+ mph, is it advisable to bring your speed down to a certain amount or safe range such as 10-20mph ?

Depends on the conditions and how comfortable you are at speed. Unless the hill is very steep and long, the air brake will be enough to hold your speed under 40mph. On a well built bicycle such as a Thorn that is in good condition, 40mph is quite safe in itself.

Because the air brake is always operating, braking from 40mph to 20mph won't take long and so I tend to let the bike run until I need to slow for a tight turn etc.

As you slow past 20mph the air brake becomes much less effective and so it will take you longer to lose that second 20mph of speed. Hence if you think it is certain or likely that you will need to brake to near a standstill, you need to begin the braking orocess in plenty of time.

Obviously if conditions are such that you may need to make unexpected emergency stops in short distances, you need to hold down the speed from which you would be stopping. In my experience it is rare that such conditions arise on very long, very steep descents.

The more likely event is that a rider simply feels exposed at speed when descending, and attempts to arrest his speed by dragging the brakes. There is plenty of reason for feeling exposed, as a fall at even 30mph in typical cycling kit will tear a lot of skin. Dragging the brakes to hold your speed under 10 or 15mph on very steep descents will work on short descents but may overheat the brakes on long descents. The solution there is to treat the long descent as a series of short descents and take rests in between while the brakes cool. I have never needed to do this  but I have never ridden in alpine conditions.
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steve216c

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Re: Braking accidents /malfunctions
« Reply #10 on: December 19, 2021, 01:45:52 pm »
Lots of talk about disc brakes. I don't have experience of that, but do of rim brakes.

Traditional rim brakes come in various guises. Cantilever brakes were all the rage when I built my first mountain bike almost 30 years ago. If set up right, they had impressive stopping power against the other brakes of the day. They were not the easiest to get set up, but worked well once correctly adjusted. But every brake change brought with it the same challenges of getting it just right.

That same bike got upgraded to V-Brakes 10 years ago. That bike had been demoted in favor of another bike that was purchased with V-Brakes which I had already found to be easier to maintain and, with slightly larger pads, a little longer lasting. A friend upgrading his group set donated me new levers and the V-Brakes for my stash of spares. One bored Sunday I upgraded the old MTB to V-Brakes and immediately gained the benefits of easier pad changes-servicing over the old cantilevers.

Fast forward to my Rohloff bike with HS33/HS11 Magura hydraulic rim brakes. Slightly better braking power vice good V-Brakes, a breeze to change the pads and brake strength adjustment a doddle with a simple allen key on each lever to adjust.

Brake failures?
The most common failure in my experience is a snapped cable on the cantilever and V-Brakes. Cheap and easy enough to fix. A cable can last years or just a few months. Getting teflon cables can help hinder wear hidden within the cable outers. A frayed cable might give you advance warning to replace, but I have had cables snap on the end stopper with little to no warning. Water ingress can cause corrosion, and sticky returns of levers when released might be a reason to check, grease or replace a cable inner.

I've never had brake rubbers break off on any system. But trying to stretch the life of a pad can be a false economy. As you adjust the brakes to use all the remaining surface you eventually expose compounds or metal within that will EAT your rims. Brake pads are cheap and can be replaced in a jiffy. Rims are not.
In the same way, riding on rim brakes during the winter can leave debris lodged in the profile of the brake pads. This will worsen your braking power and wear your rims. If you hear a scraping noise under braking, and the pads look like they have not yet reached the wear marks, then an inspection of the pads might find foreign bodies lodged in the brake rubbers. These bodies can often be quickly removed with a small knife or screwdriver and all should be good again.

On V-Brakes and Cantilever, although the brakes themselves are relatively cheap, I invariably found pads would eventually wear unevenly, especially if just tightened using adjusters on the levers without recalibrating against the rim itself- hastening service intervals. The Magura brake pads might cost a bit more, but do brake more evenly across the whole surface area- thus extending usable pad life.

Magura brakes are a closed hydraulic system. No cables to snap. Not infallible, but more reliable than cheaper cabled brakes. My Rohloff bike must be around 15 years old and still running on the same brake system. I've owned the bike around 2 years and have ridden 13,500km on it. The only brake incident was self inflicted as I adjusted the wrong screw and lost the hydraulic oil in my rear brake. Luckily I was able to fix this on a long bank holiday weekend using my Rohloff oil change syringe (same size as Magura fill hole) and some baby oil instead of Magura Royal Blood. But had I not been at home with the necessary tools and internet to help me with tips I would have been stuck without any braking power on the rear.

If you go for rim brakes, I would personally recommend Magura. But also read the manual, or watch the you tube videos BEFORE attempting adjustments the first time to avoid the sort of pickle I put myself in just described. Other than that one incident, I just find the Magura system superior in reliability and in maintenance than traditional rim brakes. But V-Brakes are also perfectly usable and safe if maintained. But consider that routine adjustments and pad replacements are a little more time consuming than Magura. However, if you were planning a longer tour, cabled brake parts and pads can be found the world over. Even larger supermarkets sometime stock these. Magura or disc brake parts are not always available in every small town bike shop off the shelf, and might force you to stop a day or so for parts to be delivered. But same deal riding a Rohloff too.

Regardless of brake system you go for- visually check your brakes regularly for signs of wear. Prevention is always better than cure. Cables are cheap, so replace on signs of wear or corrosion. Pads are cheap too. Do the same with them. If you notice the brakes are less biting than you are used to, learn how to adjust so that you always have the optimum braking power for your riding style.

At the end of the day, brake maintenance is more important that any other maintenance on your bike. A skipping chain, a creaky bottom bracket or rattling mudguard are unlikely to land you in A&E if they fail on a ride.  If your brakes fail, it could be game over for you in a second. So check regularly visually- and whenever you are out on a ride. If something is not right and cannot be fixed on the roadside, then consider all your options. Walking home is always a better option than one involving blue lights.
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