the brake needs a brand new design for EV... as of now it's used so little I kind of fear when I need it it's not going to be performant. It's not simply not engineered for current EV use case where it's touched every once in a while, I think it can go weeks without being used. However manufacturers don't have any incentive to blend it with regen from time to time, as to get it up to temperature requires a LOT of braking, which reduces the mileage/efficiency. Even Volvo recently had a recall[1] over regen braking bug, it looks like brake-by-wire system where software have control over blending brake, and decides in this case to not engage physical brakes at all even when user input suggests more braking. We just need a new brake system that can stay performant without being used at all for a long time and won't rust or jam [1] https://www.caranddriver.com/news/a65464238/volvo-brake-fail...

▲

AngryData 2 days ago | parent [-]

That is actually one reason some companies are trying to move back to all drum brakes for EVs. The drum protects the brakes from water, rust, and debri fairly well and is far more reliable when not used as often. The only real obstacle is car companies having spent the last few decades focusing all their braking and traction control features on disc brakes so they need to be reimplemented for use in drums. And really most consumer vehicles never should have stopped using drum brakes, they are better for everything except high performance racing/heat dissipation, but disc brakes were used for sales/marketing because race cars use them, and most all the improvements for brake systems started with racing so were initially and primarily designed for use with discs.

▲

potato3732842 2 days ago | parent [-]

This comment comes across a lot like the fanboys screeching about how their 1985 or 91 Toyota had a "nice" interior as if the most rattle prone 2009 GM work truck interior isn't better in every way just as a result of sheer cumulative progress. Like if you actually put A beside B and look at them without the rose tinted veneer of nostalgia it's not even a comparison.

Rusty rarely exercised drum brakes have a ton of failure modes that result in severely degraded or nonexistent performance that the average motorist probably wouldn't care about until they really need the brakes and they don't all work well enough.

The heat capacity of drums is pretty easily made noticeable, not "exceeded" to the point of substantially reduced capacity, but noticeable from the driver's seat in just a few good stops in high ambient temps (think like stop and go light to light in somewhere like DC or Miami) or one decent hill. Yeah you can polish the turd with fancy fins and materials and airflow, etc. but discs are just so much better per dollar and per pound.

Most of the problems discs have are NVH and rotor problems that are easily solved for intermittent/lesser use with the simple use of better alloys (Dexter even makes stainless for boat trailers, which are probably the ultimate example of extreme intermittent usage, so it's not like this is groundbreaking). Dominant slider pin designs these days are highly optimized for performance/NVH at the expense of longevity but there's an entire catalog of historical designs that one could easily conclude have better tradeoffs for less demanding usage.

▲

AngryData 2 days ago | parent [-]

Rusted rarely exercised drum brakes are already known to be far more reliable than rusted rarely exercised disc brakes, that is why many vehicles still or had until recently kept drum brakes in the rear where they get far less usage and get 1/10th the attention as front brakes. Or in trailers brakes that are utilized far less often.

But people already had this entire debate decades ago when disc brakes were first implemented. If you are racing or using a lot of braking power, discs are obviously better, they have better heat dissipation, they are quicker to repair and replace, more predictable for analog/dumb traction and stability control systems, and getting them rusty and dirty isn't a concern because you are racing and/or using the shit out of them. And most of the disadvantages became of little concern to consumers because when the consumer market moved towards automatic transmissions and smaller displacement engines people stopped engine braking constantly and were instead clearing their brakes off at literally every stop so dirty disc brakes stopped being a common concern. But the downsides still exist and is why disc brakes haven't taken over all applications.

Like yeah, drums have less heat capacity and worse cooling, but the entire point of regenerative braking is that you don't use them as much and so heat issues don't matter, only a small fraction of your braking force will use the physical brakes. Ideally in an EV your physical brakes are 100% a safety item, not a common usage item, and so reliability should be the top concern.

	▲	potato3732842 2 days ago \| parent [-]
		>Rusted rarely exercised drum brakes are already known to be far more reliable than rusted rarely exercised disc brakes, that is why many vehicles still or had until recently kept drum brakes in the rear where they get far less usage and get 1/10th the attention as front brakes. My ass. They might be "trouble free" in that you don't notice them not doing anything whereas a well rusted rotor will be very clearly cranky and/or felt in the brake pedal or steering wheel and perhaps the driver will elect to take it to the shop. >Or in trailers brakes that are utilized far less often. And which have a pretty strong reputation for always being in some degraded state or otherwise not working to full capacity. >Ideally in an EV your physical brakes are 100% a safety item, not a common usage item, and so reliability should be the top concern In which case a disk is far more likely to work, if poorly and loudly whereas a drum is much more likely to be completely out to lunch for some huge fraction of the cylinder's travel from a long ago seized adjuster or whatever. Yeah, drum brakes "can" be made to work. I bet wagon style friction brakes "can" be made to work. But discs are just soooo much easier. Throw an 80s style stainless slider arrangement on it so pins aren't a concern and pony up for a galvanized or stainless rotor and it becomes a basically a "good for the life of the car" item if you don't go through the pads.