What does ABS "feel" like?

[ewans]

All, what does ABS feel like?

I had a situation thismorning when i braked with moderate force, cold card/crappy road and i felt/heard a kind of grinding sound for a few secs untill i lifted off the brake pedel. I did not see the DTC light on the dash activate, should i? From what i remember from my last car this was the ABS kicking in, does that sound about right?

tia
e

 

[sp3ctre]

Yeah, that'll be it... not sure i'd describe as grinding but more like a fast rattle... you know the way you can rattle your tongue onto the top of your mouth (do I sound mad??). thththththththththththththth sort of noise. LOL

 

[ewans]

you know the way you can rattle your tongue onto the top of your mouth (do I sound mad??). thththththththththththththth sort of noise. LOL

barking mate


cheers though, wasn't breaking that hard so it caught me off gaurd and i was quite surprised by how harsh the noise was

 

[cj10jeeper]

ewans

Sounds like ABS for sure. Probably just the front NS wheel releasing momentarily as it lost grip on a damp/icy/gritty patch

You really should play with the car on a quiet B road with nothing around and run a few braking tests. I think it's important that you know what's happening, how the ABS feels and just how quick you can stop, etc. In an emergency stop you'll be amazed at the vibrations and buzzing through the pedals if you get various wheels 'locking'

Personally I've been on circuits, skid pans, rally driving and so has my wife to get a real feel for cars

 

[Aebous]

Yes the ABS is loud and will pulsate the hell out of the brake pedal. I agree 150% with cj10, find a quiet road on a wet day take the car up to about 30-40 and slam on the brakes. The ABS really is noticeable when you have to do a panic stop and the wheels are locking up just like everyone said. That said I'll say too, yours is normal.

 

[ovrkll]

Ditto on giving it a go It is quite the experience to lock one down from 60mph, but very controllable. It does sound and feel like a lot of grinding going on, but that is just the brakes rapidly pulsating.

 

[Jas667]

U can usually feel it in the peddle, like a fast vibrating, the pedal almost feels like it isnt working.

 

[Color]

The first time I felt it, my first thought was something was breaking apart
Of course, it did not take me long to reason it must have been the abs brakes.

 

[ewans]

would love the chance of getting the car on a track and thrashing the hell out of it, under instruction of course, to see where the limits are and learn how to drive quickly but safely. planning a tyre change in the summer so if i can find somewhere that does a days "hard driving" lession somewhere in scotland then i'll defo give it a go before the new rubber goes on.

 

[Zeefour]

Depends on the manufacturer, BMWs pulsate, Mercedes has no pulsating at all just a normal brake feel...

 

[pvr]

Is that so? We will have to ask Wonderboy for that as he has the SLK

 

[AlanL]

Check around with your local car clubs because some offer driving skills events that focus more on car handling basics rather than track driving events. Some chapters of BMW CCA, Porsche Club and all Audi Club chapters offer such handling skills days and one of the exercises is braking. I have been instructing for the Audi Club for the past 6 years and am always amazed at the extent that the braking skills exercise is always underestimated by the students and how surprised they are to discover how much they learned in the process.

For starters ABS exists to make sure that you NEVER can actually lock up your wheels no matter how hard you mash the brake pedal. Pure wheel lockup will cause a loss of steering control and there are no circumstances where this is useful in a car that is in motion. The whole idea of the ABS system is to pulse the application of friction on the brake rotor in a fashion that still allows you to control the vehicle while maximizing your ability to slow down.

It is a given that you need to know what your car feels like when you have engaged this system and what you can or can't do with it. Yes you can most certainly feel a chattering effect as the ABS system engages and this is not a Bad thing(TM). The first part of all braking exercises I have been a part of is to make sure that you know what this feels like. Typical course layouts for this are cones spaced so you can get up to at least 30-40mph and then go straight from the gas pedal to hard braking until the ABS system is fully engaged. Repeat until there is no sense of disorientation with how your car behaves when you do this.

A second part of the exercise is to lay out cones to simulate a lane change and then once again accelerate up to at least 30-40mph before entering the course change cones. Engage the brakes to the point of ABS intervention and then while the ABS system is fully engaged, steer to make the lane change. Yes you can do this and the whole reason for the exercise is to make sure you are aware of how ABS allows you to do it. Fully locked up wheels cause a complete loss of steering control (and leave you with flat spots on your tires) while the stuttering of ABS allows quite a bit of steering inputs to be applied while you are slowing down.

 

[tec243]

Hi ewans,

FWIW, my term for an activated ABS is pulsating. To me, it's a feeling and not a sound but rest assured, there's an accompanied noise. The harder you push down the brake and the slicker the driving surface, the quicker the pedal will go to the floor. Wet roads are a good checkout method or the same with a downhill slant which requires less speed. Technically, I think of it as the brake fluid being allowed to pass through an escape valve when the system detects a potential wheel lock regardless of pedal pressure. So, when you feel this, know that your stopping point has now become unpredictable. Be careful !! Hope this helps. ...dean

 

[Zeefour]

Is that so? We will have to ask Wonderboy for that as he has the SLK

Thats the way it works on my E55

 

[no fit state]

I can remember the first time I felt ABS kick in......Felt like the front brakes were falling apart!!

 

[Aebous]

My truck was way worse on the ABS than the Z4 is. The trucks pulsated like hell and was super loud. The Z4 is not that bad, noticeable, but not panic inducing.