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I laughed out loud when reading the wikipedia page: > Safety > The Kwid is equipped with rear drum brakes.[23][24]

monkeynotes 3y ago
Rear drum brakes are actually very effective. Definitely just as safe as alternatives, they are less prone to brake fade so I'd choose them in the mountains. From the Google: "Drum brakes can provide more braking force than an equal diameter disc brake. Drum brakes last longer because drum brakes have increased friction contact area than a disc. Drum brakes are cheaper to manufacture than disc brakes. Rear drum brakes generate lower heat."
- heisenbit 3y ago
  How can they generate less heat when the break function is to turn movement energy via friction into heat? Energy needs to go somewhere and vibration and usually noise are not enough to make much of a dent wrt. energy.
  - bluGill 3y ago
    Because they have more mass they do not get as hot for equal stopping force. However they generate the same amount of heat, it is just spread over more mass so it isn't as hot. That is also their downside: once they get hot they don't dissipate it as well and so they get brake fade faster in typical use.
    - monkeynotes 3y ago
      They don't fade until a threshold is met. This threshold is much slower onset than rotors because of all that mass. But once it's up to temperature they do fade just like rotors and they will struggle to shed that heat quickly. That's why drums are not useful on high performance cars.
  - monkeynotes 3y ago
    Drum brakes generate heat across a larger surface area, which means there is more surface area to dissipate the heat, under normal braking conditions. Technically as much energy is generated, but the heat dissipation is better in regular usage. Problem with disc brakes is they have a much smaller contact surface and the heat in the area where the calliper pinches is very focussed. Shedding that heat is much more inefficient as the steel takes a while to conduct the energy to the rest of the rotor. This is why brake fade happens much quicker for those brakes, and why there is a lot of tech on fancier disc brakes for shedding that heat. Another benefit of drum brakes is as they heat, they expand and push the drum tighter to the pad, effectively helping you brake harder as they start to fade.
- olyjohn 3y ago
  Disc brakes are still less prone to fading out. Drums hold in the heat during long downhill runs and don't cool as quickly during repeated braking events. They may generate less heat per stop, but they also don't dissipate it nearly as quickly when they do get hot. You don't want to choose them in them mountains, they're fine for a quick panic stop or two but beyond that, you're going to be much better off with a disc brake.
- deleted 3y ago
  [deleted]
- rightbyte 3y ago
  They are also more protected from the elements.
everdrive 3y ago
There's nothing wrong with rear drum brakes. They last longer than disc brakes, are cheaper, and easier to service. You don't need rear disc brakes unless you're in a performance vehicle. If people really cared about braking, they'd be making cars lighter.
- rspeele 3y ago
  I interpreted GP's comment less as "drum sucks compared to disc" and more as "well, it's got brakes" being the only listed safety feature, on a car that is sold in some markets without even airbags. It's kind of like the old "front fell off" sketch: > [Senator Collins:] No, rubber’s out .. Um, They’ve got to have a steering wheel. There’s a minimum crew requirement.” > [Interviewer:] What’s the minimum crew? > [Senator Collins:] Oh, one, I suppose. Or the Simpsons gag about the Carnivale knockoff TV set: > It features a two pronged wall plug, pre-molded hand grip wells, durable outer casing to prevent fall-apart.
  - everdrive 3y ago
    Ah, then that went right over my head. Of course, the car would certainly be less safe without brakes.
- mirsadm 3y ago
  I don't think it was a dig at drum brakes but rather listing having read brakes as a safety feature.
- callalex 3y ago
  I think the comedy comes from listing “this car has brakes” as a safety feature, as that’s the only thing they could come up with. Like, of course the car has brakes, it’s a car. I suppose the steering wheel is also a safety feature as it helps you to avoid collisions in some cases…
swalling 3y ago
> The Kwid was also criticised for being one of the Indian models not having airbags as standard. Even better
jeffbee 3y ago
As the others point out, this is a legitimate design choice. The Mazda 2 / Toyota Yaris also had drum brakes, and these were offered for sale in the USA.
fredoralive 3y ago
Looking at the source for that, it's actually a front disc, rear drums combo which isn't entirely unknown. Ford (at least in Europe) seem like it, with stuff like the Fiesta and Focus using the same combo. As I understand it the logic is discs all round is overkill for smaller cars, and the rears need a drum anyway for the handbrake, so they just go for a split setup. But most cars have discs all round anyway.

Rear drum brakes are actually very effective. Definitely just as safe as alternatives, they are less prone to brake fade so I'd choose them in the mountains. From the Google: "Drum brakes can provide more braking force than an equal diameter disc brake. Drum brakes last longer because drum brakes have increased friction contact area than a disc. Drum brakes are cheaper to manufacture than disc brakes. Rear drum brakes generate lower heat."

heisenbit 3y ago
How can they generate less heat when the break function is to turn movement energy via friction into heat? Energy needs to go somewhere and vibration and usually noise are not enough to make much of a dent wrt. energy.
- bluGill 3y ago
  Because they have more mass they do not get as hot for equal stopping force. However they generate the same amount of heat, it is just spread over more mass so it isn't as hot. That is also their downside: once they get hot they don't dissipate it as well and so they get brake fade faster in typical use.
  - monkeynotes 3y ago
    They don't fade until a threshold is met. This threshold is much slower onset than rotors because of all that mass. But once it's up to temperature they do fade just like rotors and they will struggle to shed that heat quickly. That's why drums are not useful on high performance cars.
- monkeynotes 3y ago
  Drum brakes generate heat across a larger surface area, which means there is more surface area to dissipate the heat, under normal braking conditions. Technically as much energy is generated, but the heat dissipation is better in regular usage. Problem with disc brakes is they have a much smaller contact surface and the heat in the area where the calliper pinches is very focussed. Shedding that heat is much more inefficient as the steel takes a while to conduct the energy to the rest of the rotor. This is why brake fade happens much quicker for those brakes, and why there is a lot of tech on fancier disc brakes for shedding that heat. Another benefit of drum brakes is as they heat, they expand and push the drum tighter to the pad, effectively helping you brake harder as they start to fade.
olyjohn 3y ago
Disc brakes are still less prone to fading out. Drums hold in the heat during long downhill runs and don't cool as quickly during repeated braking events. They may generate less heat per stop, but they also don't dissipate it nearly as quickly when they do get hot. You don't want to choose them in them mountains, they're fine for a quick panic stop or two but beyond that, you're going to be much better off with a disc brake.
deleted 3y ago
[deleted]
rightbyte 3y ago
They are also more protected from the elements.

everdrive 3y ago

There's nothing wrong with rear drum brakes. They last longer than disc brakes, are cheaper, and easier to service. You don't need rear disc brakes unless you're in a performance vehicle. If people really cared about braking, they'd be making cars lighter.

rspeele 3y ago
I interpreted GP's comment less as "drum sucks compared to disc" and more as "well, it's got brakes" being the only listed safety feature, on a car that is sold in some markets without even airbags. It's kind of like the old "front fell off" sketch: > [Senator Collins:] No, rubber’s out .. Um, They’ve got to have a steering wheel. There’s a minimum crew requirement.” > [Interviewer:] What’s the minimum crew? > [Senator Collins:] Oh, one, I suppose. Or the Simpsons gag about the Carnivale knockoff TV set: > It features a two pronged wall plug, pre-molded hand grip wells, durable outer casing to prevent fall-apart.
- everdrive 3y ago
  Ah, then that went right over my head. Of course, the car would certainly be less safe without brakes.
mirsadm 3y ago
I don't think it was a dig at drum brakes but rather listing having read brakes as a safety feature.
callalex 3y ago
I think the comedy comes from listing “this car has brakes” as a safety feature, as that’s the only thing they could come up with. Like, of course the car has brakes, it’s a car. I suppose the steering wheel is also a safety feature as it helps you to avoid collisions in some cases…

swalling 3y ago

> The Kwid was also criticised for being one of the Indian models not having airbags as standard. Even better

jeffbee 3y ago

As the others point out, this is a legitimate design choice. The Mazda 2 / Toyota Yaris also had drum brakes, and these were offered for sale in the USA.

fredoralive 3y ago

Looking at the source for that, it's actually a front disc, rear drums combo which isn't entirely unknown. Ford (at least in Europe) seem like it, with stuff like the Fiesta and Focus using the same combo. As I understand it the logic is discs all round is overkill for smaller cars, and the rears need a drum anyway for the handbrake, so they just go for a split setup. But most cars have discs all round anyway.