What are the chances of double brake failure?

[Phileas]

On the way to work recently I had a front brake failure - there was a ping then a scraping noise. Here’s the resulting damage:

I carried on with no front brake.

On the way home later I had a rear brake failure - one of the pads seems to have come off the backing plate:

I very cautiously carried on with a partly functioning rear brake.

[Brucey]

neither thing is as uncommon as it should be. If you check the manufacturer's recommendations, you will find that although the friction material is about 2.4mm thickness on new pads, they very rarely recommend that you wear very much more than half of it away before binning them. The chances of the above happening very greatly increase once the friction material is more than half worn away.

It is quite easy to see when rim brake blocks are worn, but by comparison keeping track of disc pad wear requires a certain amount of vigilance.

cheers

[Bonefishblues]

Is it not beyond the capability of manufacturers to insert some sort of audible warning at the point pads need changing?

[Phileas]

The front pads both have a piece missing in similar places which struck me as odd.

The rear pad failure may have been partly a result of rust on the backing plate - I rarely use the rear brake and these pads had been in for more than 3 years.

[reohn2]

Regular inspection and maintenance does help,this needn't be much more than a squirt of disc brake cleaner on the pads and rotor so wear can be observed whilst pads are in situ and without wheel removal.

[gbnz]

Is it not beyond the capability of manufacturers to insert some sort of audible warning at the point pads need changing?

Shouldn't they be thinking "outside of the box" and have an automatic recall system in place? You know, so every 1000 miles the bike would be recalled to the factory, be cleaned and checked over. Suppose if the factories over in China, they could always have a local centre for repairs.

With such a system, consumables such as the tyres, tubes, brake pads and chain could be replaced without the cyclist even having to know about it. Life would be so much easier (NB. And as the woman on Radio 4 stated last night, the Governments should pay for it - she was complaining that she was going to have spend money maintaining the freehold house she'd bought, but didn't believe she should have to pay for it, because it was expensive. The same principle should apply to bicycles)

[Brucey]

The front pads both have a piece missing in similar places which struck me as odd.

The rear pad failure may have been partly a result of rust on the backing plate - I rarely use the rear brake and these pads had been in for more than 3 years.

The front pad damage is most likely to have been caused by the pad spring breaking and being dragged through the brake. The pad spring probably only broke because it made contact with the disc and wore through, and it would most likely have done that because the pads were worn.

Cheap pads delaminate quite often regardless; when they are worn thin this is simply much more likely to happen. The amount of rust on the backings suggests to me that the corrosion happened after the delamination started, rather than being the cause of it, but it could have been the other way round; rear brakes get sprayed with salty winter water and suffer more corrosion than fronts.

You can normally see the approximate state of pad wear without taking anything apart, provided the pads are wearing uniformly; if they are not then they can either look a lot better or a bit worse than they really are. If you want to be sure that the pads are not delaminating, then removal and inspection is necessary.

cheers

[tim-b]

Hi

Is it not beyond the capability of manufacturers to insert some sort of audible warning at the point pads need changing?

...there was a ping then a scraping noise.

I hope that there aren't two of us with the same sense of humour
Regards
tim-b

[John1054]

Hi

Is it not beyond the capability of manufacturers to insert some sort of audible warning at the point pads need changing?

...there was a ping then a scraping noise.

I hope that there aren't two of us with the same sense of humour
Regards
tim-b

Maybe more of us with the same sense of humour than you think

[Brucey]

I quite often get an audible indication when other people's brakes stop working; "why are my brakes no good?"

In car disc brakes a 'squealer' isn't uncommon



and I'd imagine that something similar might be possible for bicycle brakes too. Whether it would do any good is open to question; some disc brakes squeal like crazy and folk just ride on oblivious anyway.

cheers

[Mark Berry]

I carried on with no front brake.... ...I rarely use the rear brake.... ....I had a rear brake failure.
What are the chances? Not so very surprising!

[Bmblbzzz]

You've clearly got different brake models front and rear. Not sure if this actually makes double failure any less likely. The front pads don't actually look that worn to me. I wonder if the spring failure wasn't caused by metal fatigue rather than wear on the pads bringing it into contact with the rotor?

[Phileas]

You've clearly got different brake models front and rear. Not sure if this actually makes double failure any less likely. The front pads don't actually look that worn to me. I wonder if the spring failure wasn't caused by metal fatigue rather than wear on the pads bringing it into contact with the rotor?

The front pads are relatively new so I’d agree that some other mechanism for the spring failure is indicated.

[Brucey]

You've clearly got different brake models front and rear. Not sure if this actually makes double failure any less likely. The front pads don't actually look that worn to me. I wonder if the spring failure wasn't caused by metal fatigue rather than wear on the pads bringing it into contact with the rotor?

The front pads are relatively new so I’d agree that some other mechanism for the spring failure is indicated.

"Relatively new" or not they look badly worn to me; it may be your photo doesn't tell the full story but the remaining friction material doesn't look as thick as the backing; I'd guess the total thickness of the pads is between 2.5 and 3.0mm but you can measure them and tell us. Some pads wear much faster than others, and conditions can also alter the rate of pad wear considerably. If you fitted a different type or brand of brake pads from those previously used, or the riding conditions have changed, then you can expect a different wear rate too. Another possibility is that the disc fouled the pad spring early because of some apprently trivial alignment fault. If the disc has been kissing the pad spring there are always marks on it.

cheers

[Ivor Tingting]

On the way to work recently I had a front brake failure - there was a ping then a scraping noise. Here’s the resulting damage:D3B4ED5F-1910-4126-B5C6-B9E10307FB60.jpegI carried on with no front brake.

On the way home later I had a rear brake failure - one of the pads seems to have come off the backing plate:
39C8672C-BD75-40DB-9B79-18504981C6A5.jpeg
I very cautiously carried on with a partly functioning rear brake.

I should imagine quite high looking at those pads. They are badly worn, knackered and the backing plates are very rusty. The retaining spring probably failed as the last of the linings separated from the rusty backing plate and probably took part of the retaining spring with it as it was probably weakened through corrosion as well. What condition are the discs in and how worn are they? Do you not keep your bike in a good state of repair? I mean brakes are pretty important. Neglect them at your peril.