General Cycling Discussion - Do hydraulic bicycle brakes work like ABS?

To slow you down safely instead of some brakes out there that throw you of your bike if you pull the brake too hard?.
I have recently had a new bike with hydraulic brakes and when i pull them when i go down a hill or in the rain they always slow me down safely when i pull them all the way, so i was just woundering.
My first post to the site, hello :)

Welcome to Bikeforums!

Hydraulic brakes do offer some very good modulation, but they do not act like ABS. You can still lock up your wheel with hydraulic brakes. I've done so many times.

ABS has nothing in common with bicycle disk brakes. The fact you can’t lock up the front wheel on your disk brake equipped bike in the rain is because the disk is wet not because the computer in the brake lever is modulating the brake so the wheel doesn’t lock up.

This is new to me,i know disc brake on bicycle use fluid to control the braking like an automobile,i had an encounter in my car where i need to make a quick right turn and i hit the brake very hard and the ABS kicked in, the brake pedal pulsated repeatly until i corrected the steeing action,it actually worked, but i never heard a bicycle with ABS though,what kind of bike is it? when you said you pull the brakes all the way,did you pulled hard and fast or easy and slow?

Ooops replied a bit late,haha.

Sound like your brakes may need to be bled if they only just slow you down smoothly when fully applied - or they're really crappy hydraulic disc brakes. Going down a hill or in rain, they should stop you really quickly (on a dime quick). Do the levers feel spongy at all? Can you pull them right to the bar? What brand/model are they?

Most of them will lock up easier than cable brakes.

Their kind of un-ABS.

Not at all a bad thing, once you get accustomed to them in a controlled environment.

Most of them will lock up easier than cable brakes.

Their kind of un-ABS.

Not at all a bad thing, once you get accustomed to them in a controlled environment.

So true. ABS is designed to stop without locking the wheels. Disk brakes on a bike are designed to add stopping power.

Several things will make disc brakes effective- so much so that they will stop the wheels instantly if you apply them hard enough. The same is true in that even a good set of Hydraulic disc brakes will be non-effective if they are not set up right.

Any brake- including OLD centre pull brakes- should lock up a wheel if applied hard enough. On disc brakes I would look at air in the system- Wrong fluid used in the system- Oil on the pads- Wrong quality of pads- too small a disc for the weight of the rider or just a badly set up system.

So if you can't lock up a wheel on heavy braking- stop riding the bike. And I can lock up both wheels of our Tandem- with 400 lbs all up weight. OR we can modulate the lever so that we can get the rear wheel to lift off the ground.

Hydraulic brakes and ABS are 2 entirely different things. Hydraulic brakes will lock up the wheel, which you do not want, as then, instead of stopping, your tires may skid. ABS is designed to avoid skidding, as then you have no control as to where you go, and a greater stopping distance.
If any of you ever drove a car, you may have learned to pump your brakes rather than stomp on them so that you don't skid. When you skid you lose braking power because braking depends on friction with the surface, and so you take longer to stop.
ABS prevents that by pulsing the brakes faster than you can, many times per second. And sensing when wheels are locking to avoid said locking.
ABS will probably never be available on a bike as it involves a very high pressure pump and actuator system and computer control, with sensors. Too much stuff to hang on a bike.
In a car, with ABS you do not pump the brakes. The rule to use ABS brakes in a car, in a panic or emergency stop is Stomp, Stay, Steer. Stomp on the brakes, stay on them and steer the car so you don't crash.
dc

This is new to me,i know disc brake on bicycle use fluid to control the braking like an automobile,i had an encounter in my car where i need to make a quick right turn and i hit the brake very hard and the ABS kicked in, the brake pedal pulsated repeatly until i corrected the steeing action,it actually worked, but i never heard a bicycle with ABS though,what kind of bike is it? when you said you pull the brakes all the way,did you pulled hard and fast or easy and slow?

Ooops replied a bit late,haha.

The ABS functions because the car is moving and one wheel or more is about to lock. It doesn't have anything to do with how hard you press the pedal. Mine will activate occasionally in my driveway if I'm coming to a stop and there is a thin film of ice.

The ABS functions because the car is moving and one wheel or more is about to lock. It doesn't have anything to do with how hard you press the pedal. Mine will activate occasionally in my driveway if I'm coming to a stop and there is a thin film of ice.

He didn't say anything about pedal hardness and ABS, reread is post.

Flatlander_48, i think you need to take your car to a shop to check the ABS system, only time the ABS works is when the brake pedal is slamed hard and fast,wet or dry.

The ABS functions because the car is moving and one wheel or more is about to lock. It doesn't have anything to do with how hard you press the pedal. Mine will activate occasionally in my driveway if I'm coming to a stop and there is a thin film of ice.

That sounds like it may be some kind of traction control working in conjunction with the ABS that may be malfunctioning, but I am not car expert.

That may be what Flatlander_48 refered to,VSC is popular on most new auto these day.I have it in my honda.

Flatlander_48, i think you need to take your car to a shop to check the ABS system, only time the ABS works is when the brake pedal is slamed hard and fast,wet or dry.

This is a false statement. ^^^

The ABS can activate anytime it determans a wheel lock up is imminent. The pressure applied to the pedal and or speed at which it is done has nothing to do with it.

The ABS functions because the car is moving and one wheel or more is about to lock. It doesn't have anything to do with how hard you press the pedal. Mine will activate occasionally in my driveway if I'm coming to a stop and there is a thin film of ice.

This is completely NORMAL operation for ABS.

That sounds like it may be some kind of traction control working in conjunction with the ABS that may be malfunctioning, but I am not car expert.

Traction control is basically ABS in reverse. Tire spin can be controlled either by braking pressure, reducing engine power, or the most common on modern cars with throttle actuators is throttle limiting.

In Flatlander's case, what is taking place is completely normal.

Oh ok,,i better stop the debate on that and let the experts take over, in the mean time, i am planing on a 13 miles trip to my local airport to take some pics of some old rotary and radial airplane engines, u guys take care now,u hear?

Hydraulic brakes and ABS are 2 entirely different things.

Incorrect. ABS brakes are actually a type of hydraulic brake. ABS is basically electronically controlled hydraulic brakes.

ABS brakes are actually a type of hydraulic brake.

This statement is not entirely correct either. "Hydraulic" would be considered the "type" of braking system. ABS would be considered an augmentation to it.


ABS is basically electronically controlled hydraulic brakes.

This statement is correct. But it's function is strictly to control lockup. Then there are the more modern braking systems that are COMPLETELY electronically controlled. Like on a SLK class Mercedes Benz. There is NO mechanical/hydraulic linkup between the brake pedal and the brake caliper. It is all "fly-by-wire" control.

Scary aint it? :twitchy:

He didn't say anything about pedal hardness and ABS, reread is post.

No, what he said was that he HIT THE BRAKES HARD... meaning he put a lot of pressure ON the pedal. He said NOTHING about hardness in the pedal itself. I had it right...

That sounds like it may be some kind of traction control working in conjunction with the ABS that may be malfunctioning, but I am not car expert.

The ABS works exactly as it is supposed to. It has functioned the same from brand new.

'94 Isuzu Troopers did NOT have Traction Control...

No, what he said was that he HIT THE BRAKES HARD... meaning he put a lot of pressure ON the pedal. He said NOTHING about hardness in the pedal itself. I had it right...

Sigh.

He didn't say anything about how hard he's pressing the pedals and it having anything to do with ABS. You FAIL at comprehension.

Sigh.

He didn't say anything about how hard he's pressing the pedals and it having anything to do with ABS. You FAIL at comprehension.

"and i hit the brake very hard and the ABS kicked in"

The implication was that there was some relationship between HOW you apply the brakes and WHAT the ABS does.

Oh, and you FAIL at civility...

Hey all, thanks for the replyies, please don`t argue, my brakes work very good i feel, i will pull them going down a hill, raining/sunny/snowing and they still take the time too slow me down safely even when i am going fast downhill and need too stop quick "without me falling over my bike as a sudden stop" with the front brake.
The brake down the hill when i use my front and back brake seem too slow me down really gentle without any jug of my body going forward, can someone explain why this is? thanks.

I can pull my brakes as hard as i can sometimes and still they work very good that`s the reason i was woundering.

ABS is designed to stop without locking the wheels a quote, of someone who said this, on my bike this seems too be happening but the brakes are smoothing my braking time, is there something wrong with my brakes?

No.

No bikes are designed with ABS.

so hydraulic bicycle brakes are just a better way of stopping

so hydraulic bicycle brakes are just a better way of stopping

Disk brakes in general are, IMO, a better braking system over rim brakes. Hydraulics is one form of engaging the brakes. Mechanical engagement via a cable is the other. Hydraulic over mechanical (cable) engagement of the brakes being "better" can be subjective. There are pros and cons to both methods. Hydraulic engagement, IMO, does gives better feedback and greater braking pressure.

The ABS works exactly as it is supposed to. It has functioned the same from brand new.

'94 Isuzu Troopers did NOT have Traction Control...

Like I said, I'm not a car expert. Just never had an Anti-lock Braking System activate coming out of a driveway or just when I was driving on ice, only when braking.

ABS is designed to stop without locking the wheels a quote, of someone who said this, on my bike this seems too be happening but the brakes are smoothing my braking time, is there something wrong with my brakes?

Your bike brakes don't lock either because your brakes are inherently weak, has minute or large mis-alignments, are ridden in conditions that diminish their braking power, or you are a good cyclist. ABS is a computer and sensor system. You are your bike's ABS.

ABS is designed to stop without locking the wheels a quote, of someone who said this, on my bike this seems too be happening but the brakes are smoothing my braking time, is there something wrong with my brakes?

To reiterate what others have said, a good braking system should have the capability of locking up the wheels, regardless if they are disk or rim. Being hydraulic disk, they should provide superior stopping force over other types of braking.

Having said that, don't expect your wheels to lock up in all braking scenarios. IE, going downhill on dry pavement at a considerable speed.....and a lard butt is riding the bike. ;)

I suspect you might need the system bled, and or checked for low fluid. Could be you are compressing air in the system and not fluid.

You are your bike's ABS.

Absolutely! :thumb:

Hey all, thanks for the replyies, please don`t argue, my brakes work very good i feel, i will pull them going down a hill, raining/sunny/snowing and they still take the time too slow me down safely even when i am going fast downhill and need too stop quick "without me falling over my bike as a sudden stop" with the front brake.
The brake down the hill when i use my front and back brake seem too slow me down really gentle without any jug of my body going forward, can someone explain why this is? thanks.

Use the rear brake heavier and first...

It might be my hydraulics bbrake system, i am use to it, i would buy this break if so :D

When i am going down the hill it does not matter!

It is a stoppng power?

Chuck Norris' mountain bike has ABS in his hydraulic disc brakes. He never uses brakes, though.

Anyone who has a car with ABS needs to learn what it's like when it engages. It's an interesting sensation -- mine makes a rough-sounding "RRRRR" noise and makes the brake pedal buzz. If this were to happen on a bike, you'd probably feel the brake lever vibrate. There are motorcycles now equipped with ABS brakes, and demonstrations of them side-by-side with non-ABS motorcycles make a pretty convincing case for having them.



ABS is designed to stop without locking the wheels a quote, of someone who said this, on my bike this seems too be happening but the brakes are smoothing my braking time, is there something wrong with my brakes?

Hmm... well, let's see...

Can you lock up the rear tire alone? Get yourself up to a decent speed and jam on the rear brake. Assuming that your hands aren't unusually weak, you should be able to make the rear tire skid pretty easily.

Can you lock the front brake completely? Try this: lift up the rear of the bike, squeeze the front brake lever, and see if you can make the front wheel roll. The wheel should NOT be able to roll at all if you're putting decent effort into the front brake lever.

IF you can't do either of these things, there's something wrong. To restate what others have said already -- your calipers could be out of adjustment, you might have air in the lines, you might have oil on the pads, etc.

Go here and get started:
http://www.parktool.com/repair/byregion.asp?catid=14&imageField2.x=26&imageField2.y=9

Like I said, I'm not a car expert. Just never had an Anti-lock Braking System activate coming out of a driveway or just when I was driving on ice, only when braking.

No, that wasn't quite it. Moving slowly in my driveway, slowing down under braking and on thin ice. These conditions occurred simultaneously, not exclusively...

Their kind of un-ABS.



well stated. :thumb:

Hey all, thanks for the replyies, please don`t argue, my brakes work very good i feel, i will pull them going down a hill, raining/sunny/snowing and they still take the time too slow me down safely even when i am going fast downhill and need too stop quick "without me falling over my bike as a sudden stop" with the front brake.
The brake down the hill when i use my front and back brake seem too slow me down really gentle without any jug of my body going forward, can someone explain why this is? thanks.

Firstly, ABS requires electrical input from independent wheels speed transmisometers. Those outputs have to be run through a computer then hydraulics valves open or close to modulate wheel speed. Bikes don't have this and it would be heavy and expensive to install. Most hydraulic brakes are pretty linear in that the harder you pull, the more pressure to the pads, the more stopping force. If you are just slowing down, your brakes are not functioning properly or are not of an appropriate size for your weight. Get them checked and set up by your bike shop. It may just be contaminated pads or the lines need bleeding.

Hey all, thanks for the replyies, please don`t argue, my brakes work very good i feel, i will pull them going down a hill, raining/sunny/snowing and they still take the time too slow me down safely even when i am going fast downhill and need too stop quick "without me falling over my bike as a sudden stop" with the front brake.
The brake down the hill when i use my front and back brake seem too slow me down really gentle without any jug of my body going forward, can someone explain why this is? thanks.That's because your brakes are screwed up, and not working correctly. They should be capable of lockup...it's your responsibility as a rider to handle the ABS equivalency by controlling the braking force to prevent lockup.

My experience with hydraulic disks on a bike is that they have great braking power, but still are easy to modulate to prevent lockup.

Firstly, ABS requires electrical input from independent wheels speed transmisometers.
What is a "transmisometer"? If you mean "transmissometer (http://en.wikipedia.org/wiki/Telephotometer)", there is no such component incorporated in an ABS system. We could refer to them simply as wheel speed "sensors". Normally there are two types. The more common is a two wire magnetic sensor that generates an AC signal that increases its signal’s frequency as wheel speed increases. The other is a 3 wire hall effect switch that produces a digital signal, and also increases it signal's frequency with increased wheel speed.


Those outputs have to be run through a computer then hydraulics valves open or close to modulate wheel speed.

I don't mean to be picky.....well...maybe I do. :p Wheel speed isn't modulated. It is "regulated" would be more technically accurate. The hydraulic valves are the ones being modulated (imposing a duty cycle) by the systems controller.

I don't mean to be picky.....well...maybe I do. :p Wheel speed isn't modulated. It is "regulated" would be more technically accurate. The hydraulic valves are the ones being modulated (imposing a duty cycle) by the systems controller.

On the order of 20 apply/release cycles per second, in case anyone thinks that they can physically do what ABS does...

On the order of 20 apply/release cycles per second, in case anyone thinks that they can physically do what ABS does...

Well, our "biological" grey matter thinks and operates in an analog way. Almost all electronically controlled systems are digital (1s & 0s, on or off) in their operation and any actuators being controlled by them are done so in the same manner. Pulse modulation is still an attempt at an analog curvature of control. We could achieve the same applied pressure by hand/foot in analog actuation as an ABS system does through high speed pulse modulation. Where the BIG difference is; wheel speed sensing and the determination of imminent wheel lock up and countering with the proper measure of applied force. I'm afraid our grey matter just can't measure up in that respect.

What is a "transmisometer"? If you mean "transmissometer (http://en.wikipedia.org/wiki/Telephotometer)", there is no such component incorporated in an ABS system. We could refer to them simply as wheel speed "sensors". Normally there are two types. The more common is a two wire magnetic sensor that generates an AC signal that increases its signal’s frequency as wheel speed increases. The other is a 3 wire hall effect switch that produces a digital signal, and also increases it signal's frequency with increased wheel speed.



I don't mean to be picky.....well...maybe I do. :p Wheel speed isn't modulated. It is "regulated" would be more technically accurate. The hydraulic valves are the ones being modulated (imposing a duty cycle) by the systems controller.

Yes, I guess I have to pay attention and think while typing. I meant to say transducer. Oh well, an aging brain is a funny thing. As to your second comment, yes, you are being a picky arse, and a big one but hey, everything in TX is big:). More accurately, a valve would modulate hydraulic pressure which would regulate the wheel speed. Happy?:thumb:

Regardless, due to the components required, they won't be on bicycles.

Engineering nerd alert! :D

C'mon, guys, warn us before you start geeking out... ;)

As to your second comment, yes, you are being a picky arse, and a big one but hey, everything in TX is big:).

So what are you saying? That post makes my butt look fat? Now you done hurt my one feeling. :notamused:


Regardless, due to the components required, they won't be on bicycles.

Yep, and that sums up the answer to the OP's question. :thumb: