Anti-lock Brake System - Explained

[@dhruvevolveorbeevolved508]

Man you're explanation is worth 15 mins of any other videos.

[@Manuellaborer]

I just bought my second car (SUV) and I thought it's time I need to learn a bit something about its engineering. I found others who disagree with your videos, but I'm here for general knowledge and you're very good at it!

[@richardmoore5371]

Wow! I’ve been watching you for around 4 years and never looked at the back catalogue this far back! Longevity and quality!

[@crimsonskye]

Hi Jason, can we get an updated ABS video? Your newer work goes into so much more detail and this ABS video is just so short! Hope you can make it happen, thanks for all your awesome work and content

[@EngineeringExplained]

ABS basically minimizes the stopping distance by keeping the tires at peak friction with the ground meaning maximum deceleration. This would mean quicker lap times for non-professionals, but that takes the sport of out it. Let the drivers determine where peak friction occurs. This makes it more interesting for everyone. We wouldn't want fully automated cars lapping around tracks perfectly, so drivers have to be fully responsible for how the car acts.

[@EngineeringExplained]

Well it depends on the complexity of the system. Theoretically a perfect ABS system could stop at peak grip, thus stop any car in the shortest possible distance. It just comes down to how quickly the system responds to alterations, and the duration it takes to press/release the brakes.

[@formula1nh]

Huge credit to you for taking your time to explain all this to the people like me. Going to start my Motorsports Engineering course soon and this will help me a lot. Thanks dude, from United Kingdom :)

[@EngineeringExplained]

The brakes lock if you press your brake pedal too hard, and the force exerted by your brakes on your rotors is great enough to stop the wheels from spinning. You can't steer if your wheels are locked because your tires are just sliding, therefore can't change the direction you move in.

[@EngineeringExplained]

Could be a difference in the left and right brake pads or rotors. If one comes into contact first, it could make the car behave a little strange. You can always take it to a shop and have it checked out.

[@filalleva6231]

This video could use an update. In particular you should explain how the ABS system reduces the pressure.

[@EngineeringExplained]

I don't. In my car I can get at the hand brake behind the center console. There's a little ashtray that pops out and then I could adjust the cables if I needed to. But that might not even be the right way of doing it.

[@Jjnoriega900]

dude you explain everything that I have a hard time explaining to my racer friends. I can try to explain to them about driving techniques, but they give me a puzzled look

[@EngineeringExplained]

@Benlucky13 Yes, it does. But say the tire decelerates at greater than 1 g. For most cars, this is impossible, so ABS would kick in and pump the brakes.

[@EngineeringExplained]

@Beef1188 I'm not sure but I wouldn't doubt it. Apparently even the Bugatti's emergency handbrake has ABS.

[@MustangTogunner]

its 4am and I cant stop learning more..thumbs up bro

[@EngineeringExplained]

Fair enough. Though the programming could be re-worked for a more aggressive approach, allowing the wheels to get closer to the limit of slipping than the setup you saw. Really, my point is, theoretically a computer can do it better. In reality, it could be the other way around as an experienced driver could feel the limits, and remain at them.

[@EngineeringExplained]

@Xx1eLiTe1xX Thanks! Glad you like it!

[@EngineeringExplained]

Interesting. And you didn't just get new brakes or anything? I don't really know what would cause that, unless you just brake really hard.

[@cy6386]

Short, clear, simple. Nice work bro. U just had a new subscriber

[@andrewfayi9448]

Thank you soooo much. This really helps with my Extended essay for IB

[@jaydenhills9061]

Got an assessment for Braking Systems tomorrow! This really helped me dude! I think you just saved my life xD

[@EngineeringExplained]

Depending on the system, some can individually regulate braking pressure to each tire. Not all though.

[@EngineeringExplained]

Hope so! Wouldn't want to pay for new sensors every time I replaced my tires! Apologies if I misspoke somewhere in the video.

[@EngineeringExplained]

Sure thing, I've got a whole channel of videos just for you!

[@hifiteen49]

This is a VERY old video.

[@EngineeringExplained]

Theoretically, ABS will improve the stopping distance if it can maintain peak friction between the tire and the road, without allowing it to stop too fast. There's not a definite answer. A good driver could likely stop in about the same distance by not allowing the tires to lock up. A less experienced driver would probably go a bit further than ABS would allow for.

[@ArreatPLvro]

Hey man, you popped up as "related videos" while watching some F1 and NASCAR footages. Anyway, on dry conditions, ABS will actually stop your car a bit slower than a car without ABS. The upside of ABS is that it keeps tire used in sorted fashion, meaning you will have tire worn out all "sides" at once, and it is impossible to tear down the rubber faster on one "plane" of tire. The only conditions in which ABS gives you advantages are : -damp conditions -cornering / steering while braking hard

[@anupsebastian7250]

Great video...Looking for an in depth tutorial in future regarding master cylinder, modulator container, abs pump/valves, speed sensors and how and route of the brake fluid travels while braking, and what happens with brake fluid when antilock works.

[@EngineeringExplained]

IF your wheels lock completely under braking, and you leave the pedal pressed (keeps the tires sliding) then yes, ABS will improve your stopping distance. If you're perfect with your feet/brake feel, then you could theoretically stop faster on your own - not many humans capable of this though, and I would be willing to bet a computer would win 10 out of 10 times.

[@EngineeringExplained]

Yes.

[@GubenkovED]

Hi Jason! Thanks for the video. I know that's quite old video and probably I'll be speaking into to the void, but anyways, hope it will reach out to you and you will be able find some time to answer my question. It looks like ABS is actually not the best possible (at least theoretically) way to stop because ABS system will usually cause some wheel slip whereas the most efficient way to stop is to have no slip at all. Is that fair to say? Do you think that sufficiently experienced driver can outperform ABS equipped car controlling the break power manually w/o ABS? (just found term called "Threshold braking" which is what I'm talking about)

[@EngineeringExplained]

Finally, thanks! :)

[@frannylpfan]

Thanks. I didnt know what an Anti lock brake system is. I needed to know for my Theory driving exam. Thanks. this helped.

[@chinmayachaitanya]

excellent video. But i had a doubt. what are the type of speed sensors and the type pumps used in abs system. please give an example.

[@MisterFixit69]

Im searching all over the internet , but you're the only one explaining stuff in detail, could you explain how the actual ABS pump does its magic ?

[@XHikotheproX]

Just a sort of random question.. Do you know how to adjust the handbrake on a Camry? the rears are drum brakes. Thanks! Love your channel.

[@EngineeringExplained]

Cool, thanks for sharing some numbers!

[@EngineeringExplained]

In professional racing it is not used, but it would definitely help the untrained driver (such as myself). Better to be safe and not lock up rather than slide into a wall, in my opinion.

[@Xx1eLiTe1xX]

best channel ever!

[@tarungarg606]

gr8 explanation.. but i want to know the difference between ABS and EBS can u please explain Do both have same function???

[@bshowalt14]

Now does this system reduce braking in each wheel simultaneously or all at the same time and rate?

[@EngineeringExplained]

Changing the brakes should be fine - you can always check with a dealer/mechanic to make sure.

[@tqlz-2bars]

As the ABS reads from speed sensor, is there any risk if i swap the current disc brake on my car with abs into a bigger brake kits? As far as i know, the speed sensor is not placed on the disc brake. Am i wrong?

[@mrjn6940]

hey does the anti locking braking system. have a code program in computer box?

[@girishkumar9376]

Hey nice video....but what is a dual channel abs...?

[@Barkingjohnboy]

In the dry whilst threshold braking, the difference between ABS equipped/ un-equipped cars is minimal. But as conditions get wetter/ icier, cars without ABS stop quicker. The gap between cars is metres in the wet (because the ABS cuts in too early and for longer), 10s of metres in the snow/ ice (because ABS basically prevents you from braking, but in an un-equipped car snow/slush builds up in front of the locked wheels and they effectively become a snow plough).

[@nickamarit]

I freaked out the first time I experienced ABS on my truck... Everything shook so hard...

[@jennaridgway5664]

Happened to me today I've had my license for a week. Went down an snowy hill and ended up in the guys driveway.

[@anandakrishnannair]

Thank you for the explanation!

[@youarebeyondthought]

Hey thanks so much for your videos, they're all amazing! One question, my van constantly ABS's even under normal conditions if I go to stop at a stop sign. It's fine when I'm moving fast but as I approach stopped it will always ABS a little. It never used to do this, what could be causing this?

[@Potatomonki]

would crappy tires with no grip cause the brakes to lock up under softer breaking than new grippy tires?

[@neeleshnayak4375]

perimeter disc brake system and ABS are they same?

[@ChiefGuitars666]

tires have low tread and slip a little? maybe something faulty within the ABS system?

[@keiannschyler]

does it apply to all four wheels or just the front? thank you...

[@EngineeringExplained]

All four.

[@keiannschyler]

Engineering Explained thank you for the quick reply.. i really appreciate your videos.

[@EngineeringExplained]

You're just kind of making up numbers. IF done properly, there is no reason a car with ABS should take longer to stop in the rain than one without - and since it prevents you from skidding - many times it will be better than Joe Blow slamming on his brakes and sliding into the car in front of him.

[@AkashGupta-no2ef]

with ABS how much time it usually takes for a vehicle to come to rest...a compared to normal disc brakes..??

[@badworseme]

I really like your videos (even though being an engineer and a tech myself I knew most of what you explain already) and your style of explaining technical topics as simply as possible without being boring to people who already have some knowledge in that field. But one of the main statements of this video is (in parts) wrong. An ABS System does NOT necessarily reduce the distance required to stop the vehicle. I know where you get that idea from (static COF is higher than kinetic COF) but what comes into play here (on older cars with older ABS systems) is that the tire's rubber sort of locks into the microscopic hills and valleys of the tarmac and is being ripped off which creates that burnt rubber smell and uses up a lot of the car's kinetic energy. The older ABS systems reduced the applied brake force by too much, so the ripping off rubber effect was bigger than in modern cars. And even modern systems would be inferior to a very experienced driver, at least when the conditions do not change throughout the braking. If that sweet spot of optimal braking with around 15% slip is considered 100% of the applicable braking force, a very experienced driver will be able to hold the actual braking force somewhere between 80 and 120% (meaning 12-18% slip), so close enough to the ideal spot. An ABS, however will kick in probably at about 200% (30% slip) and reduce the actual braking force to sth. like 50% (7,5% slip). Old systems basically kicked in at 666% (100% slip) went down to 0% actual braking force, releasing the brakes entirely. Where locking wheels are always reducing the distance is on loose ground like gravel or snow as locked tires build up a wedge of the loose underground material. So for us standard casual drivers in more or less modern cars, the ABS will reduce the braking distance (though not by much). But it's main idea is to keep the car controllable so that you don't understeer straight out of the corner or can turn your car around that kid that just walked up in front of you.

[@zynthos9]

You are saying the car stops faster when the wheels are locked up and sliding because the rubber being ripped off the tires uses up the car's kinetic energy? And for the numerical percentages you use, do you have any sources for where you get those numbers, or can you at least explain where they come from?

[@kaje01]

Can somebody clear something up for me? Does the ecu actually make a decision about how much braking force is likely to cause a slip? Or is the system more mechanical? Does the CPU sense no speed due to the sensor being locked up, and fully release the brakes or half release... to some arbitrary %, then resume braking once pulses from the sensor continue? I know it might seem like it doesn't matter / over thinking but I'm an automotive technician, I need to be able to diagnose and repair these systems.

[@seinfeld11123]

+kevin smith pre determined limits to wheel speed. it really depends on braking force. the abs system will continue to adjust pressure while you are breaking to get some wheel speed (no brake lock) hence the pulsating pedal its releasing clamping force on the caliper but at the same time there are threshold limts in certain speed ranges. for instance if the abs system allowed 2km/h max wheel speed. you would never stop. so there is a limit to wheel speed vs vehicle motion

[@brandonhensley3785]

Can you do a video on air brakes

[@Barkingjohnboy]

Agreed, but you can only go so far with software, it then boils down to the resolution of the encoder that is being used, and on your everyday sort of car it will be 'robust' to put it nicely (to keep it from being ruinously expensive to replace). In any case, ABS should not be extolled as something which it is not. It is merely a devise that allows you to maintain some level of steering during heavy braking.

[@XHikotheproX]

Oh yeah, thats the way my Firebird is, the ash tray can be taken out, idk if its the handbrake but theres something you can access through there. The reason I ask is because its kind of weak. It wont lock up the rear wheels unless its raining haha. Thanks for replying!

[@EngineeringExplained]

I'm an application engineer for a forklift company.

[@designchic]

Hey there... Firstly thanks for the vid very informative. I was driving a car I recently bought Peaugot 207. Anyway driving a long downhill my steering wheel locked as did the breaks after tapping multiple times. I had to use my hand break to stop. I'm unsure weather my car engine turned off while going downhill. Also there is a noticeable "release of air sound" when I press the breaks while off.. Any advice?

[@Prich038]

Lol go get your car checked out, not ask some dude on youtube, you have a serious problem with your car

[@sidewaysalways259]

Dont buy a Peugeot.....

[@balabharathi7618]

U should also explain the parts of abs. Pump and valves

[@ravisoni922]

can you please make a video explaining locking in wheels?

[@FelpsBSCC]

RAVI SONI yeah. i need it too!

[@dabeast6765]

Amazing Explanation!!!!

[@teaninja12]

is ABS good for racing purposes ?

[@EngineeringExplained]

@MustangTogunner haha thank you!

[@carlotheatheist]

hey answer my question please!! can abs or anti lock brake system have java or c++ clode? i want to make my own abs module for my rc car.

[@chewbubs3533]

Don't take my word for it, but I don't think you can use sensors to detect grip loss, so you just have to rely on loop commands. If you can though, a while or if command would be good enough.

[@Mogy336]

good video great explanation

[@RizeeyRee32]

Great Video

[@Barkingjohnboy]

It is a common misconception that ABS makes you stop faster. IT DOES NOT (at least not in cars)! The only purpose of ABS is to allow the driver to steer whilst braking, which it does as you say in the video. ABS pulses the brakes when it senses a lock up, ie: quick release and reapplication of the brakes. It takes a finite time to do this, this adds up to a noticeable differences in stopping distance between ABS equipped/ un-equipped cars, especially in wet/snowy/icy conditions.

[@abhishekmc5483]

Great job :)

[@nugenki]

so is that why when im going 80 and i step a little on the brake, the car drives as if super mis-aligned?

[@juliegogola4647]

I just bought a used car and THIS pulsing happened when I had gone down hill and THEN braked. I thought it is just my ABS BUT my mom thought it is a problem with the car';s brakes and THEN my Uncle drove it down a steep hill and said it is a brake problem. Now, I felt this in a previous car I had bought BRAND NEW and ONLY going down steep hills and braking medium to hard. I am thinking "normal ABS response" BUT my mom and Uncle (Uncle used to work on cars) are older and wiser, and THEY are going to have the used car lot "fix" the "problem". My Uncle says his BRAND NEW car has this problem, and they NEVER FIXED it. YOUR video seems to show there IS NO PROBLEM. It is how ABS works. I have written down the title of THIS video and will have my mom watch it. My Uncle says the brakes need "turned under" does that make any sense? This is an OLD video, I HOPE you will reply anyway.

[@thalarasiganriyas2566]

Very Good Explaination ,, but explain with practically it is easy to understand 🤣

[@Benlucky13]

@EngineeringExplained ah, that makes sense. and now that i think about it the tire would more easily decelerate and thus more easily register 1g (or whatever number a vehicles abs is based on), and the inverse would also be true. i guess i was thinking that somehow the rate the tire can decelerate safely would be more of a variable... thanks :D

[@Barkingjohnboy]

Fair point with the EBD, but it doesn't encompass cars that were built before its inception. Fine, Point is on snow (As tested by the Finnish car magazine, Tekniikan Maailma): Locked wheel car stopping distance - 53m. ABS car stopping distance - 64m. My main point is people should not think of ABS as a tool to stop quicker; a) because it was not explicitly designed to do so; b) That results in people who drive round with a God complex thinking 'I have ABS I'll stop'.

[@chewbubs3533]

Doesn't skidding on locked wheels also relies on the tire properties (more or less grippy) too?

[@Benlucky13]

how do they figure out how fast its physically possible to decelerate the wheel? wouldn't it depend on the surface you're driving on and how much traction you're getting? nice video, though :P

[@CensoredBeginnings]

Nothing beats a trained foot

[@jesseyoder4921]

except ABS

[@CensoredBeginnings]

Jesse Yoder Maybe the most recent ones..

[@newgenerationisbg]

+UncensoredNakedRacing Doubt you can move your foot up and down 10+ times per second though. Still, in a car with no ABS, a trained foot is as good as it's gonna get.

[@CensoredBeginnings]

I've seen race drivers get better lap times without abs than when they had it on

[@newgenerationisbg]

UncensoredNakedRacing Depends on what the ABS system was like. If it was an older car, then it's probably one of those systems that lets off on all the wheels when it senses one locked up. And of course, ABS isn't exactly "precise". As EE explained it, it lets off the brake until it senses the wheel go back up to speed, then reapplies it. If it's not done very well, then it's actually likely to slow down someone who knows the car inside and out. Then again, modern systems don't wait for the wheel to reach up to speed so they can measure it, they use other means of sensing speed and then calculate how fast the wheel should be spinning so they keep it on the edge of the grip levels. In conclusion, yes, it's likely that some people are better at controlling the brakes than some systems are, but in 99% of cases, any ABS is better than no ABS.

[@batuhancokmar7330]

I disagree about the point ABS provides the best possible breaking performance. From physics pov, it detects sudden speed drop of wheel (that is not the cause but the result of transition from static friction to dynamic friction between road and the tire), then it releases the breake of that wheel to a point that it assumes speed is ~equalised, so friction coefficent reverts back to static. Then applies in full force again only to be released after next lock-up and it goes on. Not denying ABS is a must have safety feature but its still a very clumsy method for achieving best possible stopping distances. Any competent driver (or even any average driver after practicing it a few times) will do better by applying threshold breakes and holding the friction coefficent much higher than the mere average of static+dynamic ABS provides (and that is not counting the response times of the brake system in general)

[@paulcarbuye1865]

A nice vedio but though we also need to see it practically.

[@TheWatzitooya]

Thank you :) This makes sense...

[@zynthos9]

Why do people say ABS increases (makes worse) stopping distance in snow?

[@powertothebauer296]

Please my Friend learn your Lessons about ABS Systems again. Where the sensors and so on is Mounted. This you can see clearly on BMW Motorcycle .If you take the effort and crawl under a car you will have an easy spot on it

[@EngineeringExplained]

No worries, good to know you're not just trolling haha

[@EngineeringExplained]

Yep, sad that that's a reality.

[@Barkingjohnboy]

I apologise for not having the necessary data to back up my claims. It's not my information to give away, as it belongs to the race team who were testing their Evo (I was just being nosy at the time). So no, I am not making numbers up, I am commenting on the data and testing I saw. I never disputed that it was a bad thing to have, because yes, it will prevent lock up 10 out of 10 times. I was just pointing out using ABS is not necessarily the fastest way to stop your car.

[@TheCgrules]

My anti-lock brakes stopped working. A mechanic told me its not important unless your brakes in general are old.

[@Beef1188]

Im told the Bugatti Veyron and his braking system is so advanced that in emergency braking that the computer calculates the maximum necesary force to maintain grip thousands of times a second. But the sistem itself is completely unconventional, fully digital in respect that it doesn't have such a component described here. Mind you, its second hand rumor so I don't know if its true, maybe you know?

[@orgigeorgie]

Good video. Ha try and see ABS on gravel, shits itself.

[@alexcacares6547]

You look like a young Steve Jobs

[@kevinveetec]

abs sensors are on the calipers not the tyres!

[@TheWatzitooya]

I'm sorry, but I'm a little confused because I don't know what causes brakes to lock. Why do brakes lock? And why can't you steer while braking without ABS? Sorry if the answer's obvious, but I'm just a little confused...

[@DankosDIY]

Wow does it works? Not what it does. HOW DOES IT WORK? WHat happens inside ?

[@AuMechanic]

Cadence Braking for dummies.

[@Barkingjohnboy]

Or more truthfully 'I have all these driver aids, I can't crash'.

[@bossbanks7719]

U should like Ross from friends

[@Tpakysjd]

Im from future thx for explaining

[@alial-ali865]

ABS

[@dabeast6765]

Also you look like a smart Ashton Kutcher! :D just saying

[@RzVids]

So without ABS, can't I just repeatedly press the brakes?

[@ryanatta]

+RzVids you could but i doubt you would be able to match some ABS systems that can relieve and reapply braking force 15 times a second.

[@mattb4579]

+RzVids In theory that makes sense. Just don't slam the breaks and lift off a little bit every once in a while. I doubt that it'd be any where near as effective as the system because humans can't monitor the breaking limit and can't switch the breaks on and off as quick as the system can. If you get it right then it could work I guess, but otherwise I'm not sure.

[@seinfeld11123]

+RzVids you can modulate the pedal. meaning if you feel it lock up. you will feel the car almost accelerate. and when you let off the brake you will actually slow down even while releasing brake pressure. because you use the rules of grip and adhesion

[@AuMechanic]

+rynatta No, it may sample the wheel speed at 15 times a second but it ;cycles the ABS ;at a time period that is the time it takes the wheel to re accelerate to speed and begin to lock again, which can be 2 or 3 times a second on bitumen, you can hear the hydraulic hammering in the brake lines as it cycles, on snow the cycle time can be much longer resulting in very much longer braking distance than if you had just held the brakes on to some degree. ABS is not designed to reduce braking distances it is design to allow you to steer the car under hard brakes to avoid an object where it will not steer at all with front wheels locked up.

[@ryanatta]

AusMecham if you slam the brakes on a car with no abs the amount of braking force exceeds the amount of traction a car's tyres have and hence is why you lose traction and takes longer to brake. This is more pronounced in wet/snowy conditions where traction is seriously impaired. It's exactly like smashing the throttle from a stand still, you lose traction and lose control whilst taking longer to get to speed. ABS modulates the brake pressure when 90% of people will smash the brakes when they perceive danger. I agree that you can reduce braking distance as compared to ABS if you know exactly how much pressure to apply proportionate to how much traction your tires have but if this is done correctly ABS should not kick in as traction is not lost. Bottom line: ABS exists for when 90% of people smash their brakes and it would be useless/unsafe to have the ability to disable it or not include it at all.