Carbon ceramic brakes in heavy rain

[bimmerboyE92]

I don't have CCBs. However, I've noticed that my brakes get noticeably wetter when driving in the rain with the stock 19" rims compared to the stock 18" rims.

[neilum]

Originally Posted by dubsesd

This is normal on steel brakes as well. Nothing new here

Can you elaborate?

I have steel brakes and in very wet conditions at highway speeds the brakes have about 30% of their normal bite/power if the brakes aren't applied for a few minutes. It has scared the shit out of me several times. Once they bite for ~2 sec they are fine, but the first application of them they are basically useless. Then, if I drive again for a few minutes and don't use them, this will repeat again.

I've been driving for 21 yrs and none of my other cars have done this.

What is the reason for this behavior with the M's brakes, even the steel setup?

[Wills2]

Originally Posted by Colinv6

I've had this on steel brakes too! It's very scary and the brakes are non existent for 2-3 seconds (a long time on an off ramp).

Yep! After a period of driving in the heavy rain the first application of the brake pedal feels awful.

[AIRPOWER]

I thought BMW had a system in place that when you used your rain sensor and the wipers came on, the brake pads would ever so lightly touch the rotor to keep all the components dry for emergency braking.

I had this in my 09 335i and could feel the brake pedal pulse with the wipers (especially when stopped).

I have not noticed it in this car though......does the ///M not have this?

[neilum]

Originally Posted by AIRPOWER

I thought BMW had a system in place that when you used your rain sensor and the wipers came on, the brake pads would ever so lightly touch the rotor to keep all the components dry for emergency braking.

I had this in my 09 335i and could feel the brake pedal pulse with the wipers (especially when stopped).

I have not noticed it in this car though......does the ///M not have this?

Either my car is broken or the M doesn't. The steel brakes in the wet are downright scary sometimes.

Curious if anyone knows.

[jim996]

Carbon brakes are designed for race track applications. They need to be hot to work properly. Even Moto GP bikes switch to steel brakes for a wet race. I've no idea at all why people are speccing them for road cars?

[CanAutM3]

Originally Posted by jim996

Carbon brakes are designed for race track applications. I've no idea at all why people are speccing them for road cars?

True for Carbon-Carbon brakes, not CCB. There are no race cars (that I know of) that use CCB. CCB are primarily meant for street use with occasional track use.

[erdisaral]

I had the same problem a week ago while I was driving on highway. The rain was so heavy!!! I was driving downhill and when I used the brake, it didn't slow down like it should do. I have ceramic brakes as well. It was actually scary because it could have gone worse! Brakes performed perfect at the track after an hour.😂

[DreamSlider ///M]

Originally Posted by neilum

Either my car is broken or the M doesn't. The steel brakes in the wet are downright scary sometimes.

Curious if anyone knows.

I do not know from personal experience (no rain in the last week). I do know that it was specially mentioned as a feature of the car by my delivery specialist at PCD last week.

[phoenx]

I got caught in heavy rain during my ED. I was exiting the autobahn towards a rest area and I pretty much had to slam on the brakes to get the car to slow down. It was the first time I had driven my M3 too. Hasn't really happened since. It really does freak you out when it happens but I think you should be ok. If the problem continues, take it to the dealership and see what they can tell you.

edit: I have CCB's.

[rmedeir1]

I have had the same situation for 3 different scenarios...

1. Straight out of car wash - happens for maybe a 20foot roll before they catch. I always apply brakes soon after the car wash.

2. Heavy rain - even after driving on the highway for a long period in very heavy, heavy rain (say 10 miles uninterrupted) in colder weather (about below 50) this situation has occurred twice in the last 2 years.

3. Start-up in freezing weather (not garaged)

You have to be aware of these scenarios and always warm the brakes up a little at first and you are good. Not as dangerous as the perceptions or comments made.

[CAOZKAN]

Originally Posted by rmedeir1

I have had the same situation for 3 different scenarios...

1. Straight out of car wash - happens for maybe a 20foot roll before they catch. I always apply brakes soon after the car wash.

2. Heavy rain - even after driving on the highway for a long period in very heavy, heavy rain (say 10 miles uninterrupted) in colder weather (about below 50) this situation has occurred twice in the last 2 years.

3. Start-up in freezing weather (not garaged)

You have to be aware of these scenarios and always warm the brakes up a little at first and you are good. Not as dangerous as the perceptions or comments made.

You must be joking, going with highway speeds and having brake latency is not dangerous for you?

[rmedeir1]

When u take the precautions I mention no issue. Not dangerous. Not joking. Issue occurrence extremely rare, but to be clear the 3rd (for #2) variable is when you flood the wheel wells with water not just heavy rain alone.

[Mantvis]

Exactly the same thing with my M3 with CCB... If its raining real hard just keep distance, and if you have to make an emergency stop just pump the brake instead of just slamming it.

Originally Posted by rmedeir1

I have had the same situation for 3 different scenarios...

1. Straight out of car wash - happens for maybe a 20foot roll before they catch. I always apply brakes soon after the car wash.

2. Heavy rain - even after driving on the highway for a long period in very heavy, heavy rain (say 10 miles uninterrupted) in colder weather (about below 50) this situation has occurred twice in the last 2 years.

3. Start-up in freezing weather (not garaged)

You have to be aware of these scenarios and always warm the brakes up a little at first and you are good. Not as dangerous as the perceptions or comments made.

[DreamSlider ///M]

Had this happen to me last week when it was raining. It terrified me for the moment they took to engage. Fortunately I was on a surface street and had a lot of space around me. Certainly something to be aware of for owners of these.

[bd307]

Originally Posted by AIRPOWER

I thought BMW had a system in place that when you used your rain sensor and the wipers came on, the brake pads would ever so lightly touch the rotor to keep all the components dry for emergency braking.

I had this in my 09 335i and could feel the brake pedal pulse with the wipers (especially when stopped).

I have not noticed it in this car though......does the ///M not have this?

I am pretty sure you are just joking.

[AIRPOWER]

Originally Posted by bd307

I am pretty sure you are just joking.

No I am not. My 335i had this.

[Mantvis]

Right from BMW:
"Brake Drying is a highly valuable function that takes advantage of the fact that all current BMW models have a rain sensor, whose primary function is to operate the windshield wipers according to rain impinging on the windshield.

Any film of water between brake pad and rotor, no matter how thin, can briefly impair braking. Acting on input from this sensor, the brake pads are periodically brought up to the rotors, just enough to eliminate any film of water but not enough to cause any brake application.

Benefit:
•Preserves normal braking in wet-weather driving"

[AIRPOWER]

Originally Posted by Mantvis

Right from BMW:
"Brake Drying is a highly valuable function that takes advantage of the fact that all current BMW models have a rain sensor, whose primary function is to operate the windshield wipers according to rain impinging on the windshield.

Any film of water between brake pad and rotor, no matter how thin, can briefly impair braking. Acting on input from this sensor, the brake pads are periodically brought up to the rotors, just enough to eliminate any film of water but not enough to cause any brake application.

Benefit:
•Preserves normal braking in wet-weather driving"

Mantvis, thanks for finding this. I am glad BMW kept this technology.

[shay2nak]

Maybe this is not on CCBs from what I'm reading or then it's malfunctioned??

[Mantvis]

Originally Posted by shay2nak

Maybe this is not on CCBs from what I'm reading or then it's malfunctioned??

The M cars do no not have it

[CAOZKAN]

Originally Posted by Mantvis

The M cars do no not have it

Maybe it can be coded in? I would love to have it, after my rainy highway incident.