this post was submitted on 06 May 2026
183 points (98.4% liked)
Technology
84434 readers
3926 users here now
This is a most excellent place for technology news and articles.
Our Rules
- Follow the lemmy.world rules.
- Only tech related news or articles.
- Be excellent to each other!
- Mod approved content bots can post up to 10 articles per day.
- Threads asking for personal tech support may be deleted.
- Politics threads may be removed.
- No memes allowed as posts, OK to post as comments.
- Only approved bots from the list below, this includes using AI responses and summaries. To ask if your bot can be added please contact a mod.
- Check for duplicates before posting, duplicates may be removed
- Accounts 7 days and younger will have their posts automatically removed.
Approved Bots
founded 2 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
Well that sounds terrifying. There's a reason why the brake hydraulicsystem is actually two separate hydraulic systems, for diagonally opposite wheels. The only single-point-of-failure is the brake pedal.
Their leaving out the critical details on how this will electric system will be fail safe, or even legal.
Maybe they'll return to spring actuated mechanical brakes that are released when everything is working. (More common in heavy industry, and I believe also truck brakes)
Yeah no. Hydraulic brakes can fail at any of the slave cylinders or the master cylinder.
If a single slave cylinder fails there is still the other pair in a tandem system but braking effectiveness is substantially reduced.
The tiniest tear in the seals of a master cylinder will lead to total and absolute brake failure. Your only brake left is the hand brake.
That only happens on one wheeled cars.
And even then, only on cars with those stupid electronic parking brakes instead of a proper mechanical emergency brake.
Pulling the handbrake on a moving vehicle is generally speaking really bad idea. It'll stop, yeah, but it'll be really scary for a moment before that.
Scary? Maybe if it's your first time doing it. It engages specific brakes in a specific way. Pull it slowly to see how it works.
Go pull a handbrake on a highway speed simulating an emergency situation and then report back. I'll wait.
I've done it. With the once-upon-a-time-cars it was just a metal wire connected to the drum brakes, you could easily modulate it.
moving the goalposts already are we?
There are only two reasons to pull the emergency brake in a moving vehicle: either you're messing around and making the car fishtail was the desired outcome, or your regular brakes failed and you need to stop fast instead of just coasting to a halt. In the latter case, the vast majority of people will lose control of the car immediately and it will be absolutely terrifying experience.
...what about handbrake turns?
That's the messing around part.
Was probably being too literal. Handbrake turns aren’t fishtailing and while I’ve only ever done them to mess around, they’re also used in rally and whatnot
Edit: I searched and while I always heard fishtailing used for uncontrolled rear slippage, it seems it can also just refer to oversteer? Didn’t know
Yeah I'm not a native english speaker so I'm not sure about the correct terminology. Oversteer is probably better one here.
how dare someone drive in a manner you disapprove of and then not get in an accident.
I genuinely have no clue what you're even disagreeing with.
nor do i. well i do, i just don't understand why.
Fun you mean 😬😁
How do you go drifting in the winter? That is quite common in my circles in Manitoba Canada. Lots of us grow up assuming that the e-brake is for drifting on ice (also largely because of how devastatingly flat the prairies are).
By pulling the handbrake if it's a FWD car or dumping the clutch if it's an RWD.
Tell that to rally drivers.
Come with me on an ADHD journey!
Spring actuated, or well, any type of ‘fail closed’ brake design would definitely work.
But what happens if it fails closed (due to no power - the only failure mode I’ve considered below) and the vehicle needs to be moved?
Are they gonna do that thing they do with elevator emergency brakes with the spinning balls that engage the brakes only if a certain inertial threshold is reached? That way as long as they aren’t going too fast, the car can be pushed off the road?
Or are they gonna let you plug in a phone to charge the brake system enough to disengage the failsafe?
Maybe there will be a sweet-ass lever under the center console like the one in the first Jurassic Park movie where people have to pump it to prime the system?
My favorite iteration of this nonsensical idea is that new cars are going to come with a crank in the front, like old-school model T’s, so that in an emergency, people can wind up their cars to release the brakes.
(Please consider all of the above as me having too much time on my hands, and not a real critique of your statements. I think failsafes are a good idea. I’m just a silly.)
Too late, I just launched a new production with exactly your ideas!
Theres trailers for that as the other comments mentioned but maybe it could be designed in such a way that you could clip jumper cables on from another vehicle or car battery to open the brakes maybe even give normal braking power to the pedal so one can safely stop again, something that hydraulic brakes arent good at. (Stopping a car thats off, where the brake booster isint powered)
the same as all other cars with locked axles, they tow on a wheel sub trailer.
I was thinking about pushing it off the road for the every-person. Not just transport. But don’t take me too seriously. I’m no mechanomagician.
Like if the engine dies on a roadway and now that lane is completely blocked until a truck can come pick it up? Where normally someone would get out and push it to the side of the road so traffic could flow while they wait? I think your concern is valid.
What happens if it fails closed (due to no power - the only failure mode I’ve considered below) and the vehicle needs to keep moving, like on a busy highway?
Suddenly engaging all 4 wheels at maximum stopping power isn't always a safe thing to do.
I've had hydraulic brakes fail closed. Shop fucked up the repair. What's your point?
Shops can fuck up all kinds of things, how often do hydraulic brakes fail closed?
Air brakes fail closed and buses and trucks have those. Therefore we already have brake systems failing closed and it hasn't been considered a big deal.
Solved with ejector seats, obvs.
If you can’t physically handle explosive bolts firing within close proximity of your ears to shear the roof off your vehicle, and the subsequent 12-20G’s of acceleration as you’re unexpectedly launched skyward, then what are you even doing in a vehicle!?
As to how to trigger the explosives and rocket motors when the power has gone out? Independent emergency batteries that activate when a power loss is detected.
Could these batteries be used to power the braking system instead of a dangerous, cartoonishly violent, and ill-advised fantasy? Yes.
Will they be? No.
Diagonally opposite? No, it's front and rear. However, brake fluid reservoirs haven't been split for decades now, so if your fluid leaks out, every wheel is affected. It's still highly unlikely that you're going to have a leak that suddenly dumps all the fluid, unless you're driving a very old and rotten car, in which case you probably know what you've gotten into.
Brakes that "fail on" while the vehicle is moving can be catastrophic for some dingus in a car. Truck drivers have much more intensive training and specialized licensing.
Hydraulic brakes in a car will still stop the car in a relatively controlled fashion even if the system is incredibly degraded, and they are purely mechanical. With wires, there's a chance that the brakes go from "working normally" to "not working at all" without any warning. Hydraulic brakes fail gradually.
Yeah, I was going 55 when my rear brake failed on. I'm surprised the axle didn't snap. I was on a narrow country road and was lucky to keep the car in my lane. I had to pull a 3 point turn then reverse to the gas station just ahead because my rear axle would only spin that direction. It was not my best night.
No. It is diagonally opposite. All rear will cause the veichle to fishtail and similar issues with all front braking in case of failure. Thus the parking brake is infact not an emergency brake but a parking brake.
This is a problem I am encountering more and more frequently with "new tech."
With old tech, the system would degrade - a little bit at a time, you could tell that something wasn't right but it was still functional. You'd have warnings, often 1000 miles or more of clear warning that you need to get it serviced before you get stranded somewhere. Sure, not always, but often.
More often these days, my vehicles go from "everything is awesome" straight to: refuse to start or move mode. Sure, there are some "limp home" modes, but I have gone from zero warnings on the dash, zero unusual behavior, straight to no longer running / will not start, 3 times in the last 5 years (on 3 different vehicles) - each time it was "something new" that had that binary mode: working / not working and you're gonna have to get a tow. I have been towed in the past with "old tech" that failed on the highway (blown radiator hose, rusted ground point on the fuel pump wire), but not for such picayune little electrical/software details like these recent failures.
It would be trivial to keep the car from starting if the brakes don't pass a system check, and make the main electric motor of the car apply maximum regen braking if the system fails en route.
And you'd have one motor per wheel, so if one fails you still have more than enough braking power.
In principle, a system based on electric motors should be a lot more reliable than one based on hydraulics.
Modern hydraulic systems have two lines going to the ABS pump and then from there on each wheel gets its own line. At most you'd lose two wheels at once.
Split systems have been common for the last 4 or 5 centuries at least, but the older ones were just two way split.