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Comment by cyberax | Hacker News Reader

Anybody who ever driven an EV, would have told that the initial scare about brake dust was pure nonsense.

EVs barely use frictional brakes, with regen performing most of the braking action. Frictional brakes only really come into play to slow down from around ~5 mph to a complete stop.

And even that can be eliminated by essentially running the motor backwards, at low torque. This mode of braking is sometimes used on train engines as an emergency braking method.

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How does this generally work wrt brakes needing to be used occasionally to not rust shut? Even with an ICE car if you don't drive a lot, and drive in a fuel efficient way (e.g. coasting towards red lights) this can be an issue resulting in an expensive surprise when you need to replace disks long before they are worn out.

Some EVs (Teslas are ones I know of) have software that occasionally lightly applies the brakes to keep them clean.

Also, on EVs with LFP batteries the brakes do get used a bit more, because a full and/or cold pack usually can only take very limited power from regenerative braking. Depending on the implementation in the vehicle, brakes are either applied automatically to still allow for one-pedal-driving (aka. "brake blending", making the difference unnoticeable to the driver), or throttle-pedal regen is simply capped and the driver has to use the brake pedal when they notice that regen power is not sufficient.

Have Tesla with badly corroded rear brake discs. Software does clearly not help here. It was very bad at the end of winter. Now it’s getting better in spring. I am curious how does it look in autumn. Trying to use mechanical brakes occasionally. I had same story with corroded rear brakes on BMW. The solution was mechanical handbrake.

Which one do you have? I had the same issues with my '19 M3P, all the brakes were badly corroded a year into the lease. Apparently the software to keep this under control came a bit later into the lifecycle, and is not very effective if the problem is already apparent. Anecdotally, what was _very_ effective at cleaning up the brakes was blasting it for a couple laps around the Nürburgring Nordschleife - the grooves / corrosion went away almost completely :D

Now I have a RWD Model 3 with an LFP pack (SR+/"base model"), and have to use the brakes much more than with the old car (that had an NMC pack and almost never limited regen). Over two years in, brakes seem good as new, hopefully they stay this way.

Model Y AWD which saw its first winter recently. So the software should be the recent one. Left side is much worse than right side. Quality problem? Maybe swapping discs before winter could save them. Or replace them before TÜV check, the parts aren’t that expensive.

There were actually cases of that happening with some EVs (Chevy Volt, AFAIR).

They fixed it by having the software to apply frictional brakes once in a while to keep the rotors clean.

I have an EV with 150k miles, and the brake pads are barely worn. They are going to outlast it.

With my cars I just put them in neutral and brake down a hill once a month.

Never had any issue with rust.

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