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Drum brakes have been around for a century, afaik they're more robust than discs but "lower performance". These look like a variation on a pretty standard desig

by sottol 3y ago

Drum brakes have been around for a century, afaik they're more robust than discs but "lower performance". These look like a variation on a pretty standard design at first scan.

wlesieutre 3y ago
Lower performance brakes is a hard trade off to make when EVs are also heavier than gas cars
- ch_sm 3y ago
  I think the idea is that engine braking (regenerative braking) makes up for the difference.
  - wlesieutre 3y ago
    Can you rely on that if someone charges their car at elevation and then has to drive down a mountain?
    - dangrossman 3y ago
      Yes, by not charging to 100%, so you have some room for additional charging by regenerative braking. Virtually all EVs come with a setting, usually enabled by default, that stops the charge at a preset percentage, like 80 or 90%. Chevy aptly calls theirs "hilltop reserve".
- ZeroGravitas 3y ago
  Drum brakes are one of the many things that contribute towards EVs becoming lighter than equivalent ICE cars over time, as they weigh less than disc brakes (about 25% lighter, 10lbs maybe, and unsprung weight too). As the link states, they also increase efficiency, and that allows for smaller batteries, less weight. They're also looking into lighter weight aluminium disc brakes because EVs use them less, and it prevents issues with low usage disc brakes rusting.
- ezfe 3y ago
  My PHEV weighs 30% more than the non-PHEV version, yet my brakes have lasted longer than anyone I read online with the regular version of my car. This is because of regenerative braking not using the brake pads, using the motor instead.
amluto 3y ago
I’ve never played with a drum brake, but I’ve assumed that dust is ejected somehow in normal operation. The Continental design is sealed to contain the dust. Maybe dust in the drum isn’t a problem? Or maybe it’s designed so the dust accumulates somewhere other than on the friction surface inside the drum?

by sottol 3y ago

Drum brakes have been around for a century, afaik they're more robust than discs but "lower performance". These look like a variation on a pretty standard design at first scan.

wlesieutre 3y ago

Lower performance brakes is a hard trade off to make when EVs are also heavier than gas cars

ch_sm 3y ago
I think the idea is that engine braking (regenerative braking) makes up for the difference.
- wlesieutre 3y ago
  Can you rely on that if someone charges their car at elevation and then has to drive down a mountain?
  - dangrossman 3y ago
    Yes, by not charging to 100%, so you have some room for additional charging by regenerative braking. Virtually all EVs come with a setting, usually enabled by default, that stops the charge at a preset percentage, like 80 or 90%. Chevy aptly calls theirs "hilltop reserve".
ZeroGravitas 3y ago
Drum brakes are one of the many things that contribute towards EVs becoming lighter than equivalent ICE cars over time, as they weigh less than disc brakes (about 25% lighter, 10lbs maybe, and unsprung weight too). As the link states, they also increase efficiency, and that allows for smaller batteries, less weight. They're also looking into lighter weight aluminium disc brakes because EVs use them less, and it prevents issues with low usage disc brakes rusting.
ezfe 3y ago
My PHEV weighs 30% more than the non-PHEV version, yet my brakes have lasted longer than anyone I read online with the regular version of my car. This is because of regenerative braking not using the brake pads, using the motor instead.

amluto 3y ago

I’ve never played with a drum brake, but I’ve assumed that dust is ejected somehow in normal operation. The Continental design is sealed to contain the dust. Maybe dust in the drum isn’t a problem? Or maybe it’s designed so the dust accumulates somewhere other than on the friction surface inside the drum?