Hacker News Reader

Comment by seanmcdirmid | Hacker News Reader

> There's still brakes, suspensions, tires, etc. to sell to EV buyers.

The brakes last a lot longer because of regen, everything else applies but is pretty marginal, although I had to pay BMW $500 to replace a tire on my i4 because of a nail. I could have shopped around for that I guess.

View on HN

If you don't use your brakes and just regen all the time, you run the risk of having your brakes rust.

https://nrsbrakes.com/blogs/supporting-articles/the-unused-b...

Yes, you are encouraged to slam on your brakes at least once a month to get the rust off. I live on the west coast (rain but low humidity and hardly any snow), so its less of an issue.

You'd think with all that electronics it would be smart enough to use real brakes every now and then. The plug in hybrid Prius runs the gas engine every 100 miles or so.

Some cars do this. Audi and Porsche (if I recall correctly) use the disc brakes for the first couple stops each drive to knock off the rust if there's any build up. I think I remember reading that Ford uses the real brakes if you're under 5mph. I'm sure other manufacturers do something similar (other than Tesla which apparently doesn't do anything to help).

I don't think that is a good feel, you sort of get a feel for how fast you slow down with regenerative braking and throwing real brakes into the mix randomly sometimes would make for a horrible driving experience.

Better to have a reminder, surely the car could figure that one out.

Do we know rust on brakes is even a problem before assuming the electronics aren't smart enough?

Yes, it's studied. Rust and metal have different frictional properties, and the rotors produce different torques when the brakes are applied. This results in a sort of uneven shuddering when you use the brakes if they're heavily corroded.

It's not immediately deadly, but your brakes are one of the most important safety systems on the vehicle. They should be in good working order.

Totally, I'm not thinking for a second that you are wrong there. I'm not saying rust on brakes isn't bad. What I'm questioning is whether rust buildup is an actual issue happening for most EV drivers right now.

I'm genuinely curious because, for no good reason, I take pride in the fact that most trips I don't even touch the brake pedal other than to come to a complete stop and only when parking, etc where you can't regen all the way to a stop.

First read your owner's manual to see if it says anything about this.

My EV for example has a brake cleaning mode that turns off regeneration for approximately the next 10 times you use the brakes.

Using that is probably going to be safer than slamming on the brakes.

If anything unsafe happens when you slam on your brakes, you need to get your car serviced. Just do it on a quiet street and check your rearview mirror for someone following too closely (a good habit any time you brake).

iirc some OEMs will automatically apply the brakes lightly during regular driving from time to time to counteract this

I know Rivian does this.

Reply on news.ycombinator.com