Wet brakes

[f1eng]

Travelled yesterday in very wet conditions with the first 10 miles or so on part flooded country roads driving through water inches deep.
The brakes performed exactly as I would expect, the regenerative braking was obviously unaffected but braking at low speed was typical "cleaning the water film off the disc" feel I would expect followed after seconds with normal performance.

I have my favoured cast iron rotors.

I didn't think wet braking was an inherent problem in the Taycan before this and am quite sure now that it is not.

People with a problem probably just need their brakes bleeding thoroughly with the correct procedure.

I don't know how plated or ceramic discs would be in the same conditions, of course.

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[W1NGE]

Travelled yesterday in very wet conditions with the first 10 miles or so on part flooded country roads driving through water inches thick.
The brakes performed exactly as I would expect, the regenerative braking was obviously unaffected but braking at low speed was typical "cleaning the water film off the disc" feel I would expect followed after seconds with normal performance.

I have my favoured cast iron rotors.

I didn't think wet braking was an inherent problem in the Taycan before this and am quite sure now that it is not.

People with a problem probably just need their brakes bleeding thoroughly with the correct procedure.

I don't know how plated or ceramic discs would be in the same conditions, of course.

I have the PSCB brakes on my GTS ST and they are infinitely superior to the ones on my 4S - braking in wet is much more assured and outstanding in the dry - even a low speed where the 4S would require more pressure.

I seem to remember Merc introduced a system which when wet would automatically skim the rotors to keep them dry - simple genius really and not sure why everyone else didn't latch on to this.

 

[Sidicks]

I have the PSCB brakes on my GTS ST and they are infinitely superior to the ones on my 4S - braking in wet is much more assured and outstanding in the dry - even a low speed where the 4S would require more pressure.

Porsche don’t claim any stopping benefits of the PSCB compared to the standard brakes, only shinier, less corrosion, less brake dust and increased longevity. Any greater stopping benefits will simply due to the increased size of the PSCB discs (410mm at the front), although the standard discs on the GTS (360mm) are already bigger than the discs on the 4S etc. Given Porsche’s reputation with brakes, personally I’m not convinced that the standard set-up was not up to the job in day-to-day use.

I seem to remember Merc introduced a system which when wet would automatically skim the rotors to keep them dry - simple genius really and not sure why everyone else didn't latch on to this.

I’m sure I remember reading about this on my 997 C4S - if the system senses you suddenly lifting off the throttle, it automatically applies just enough pressure on the brake disc to clean it of any residual water, ready for any actual braking needed.

 

[Dee]

I have PCCBs and indeed, coming out of the carwash you must be aware of the water/soap film on the disks/pads.
One firm tap on the brakes will make it disappear, just like any other car.
In heavy rain I didn't notice any difference though.
I have to say, I don't brake that hard in the rain cuz I always take precautions when it's pouring, especially cuz I have wide tires.
In the dry they stick twice as good but in the rain you loose half.
But overall I never experienced any brake issues in heavy rain whatsoever.

 

[Scandinavian]

I also have not had any real problems with very wet brakes in thunderstorms. There is the same initial cleaning as in other cars needed. The large 410 mm PSCB with 10 pot calipers need some extra initial pressure to clean but after that they are good.

I think Porsche test their brakes before model release and they all have great stopping power. I think the test included limited or no fading after 25 stops from something like 80% Vmax to 40 km/h or similar.

Stopping distances could be more dependent on tyres than brakes I assume?

 

[f1eng]

I have the PSCB brakes on my GTS ST and they are infinitely superior to the ones on my 4S - braking in wet is much more assured and outstanding in the dry - even a low speed where the 4S would require more pressure.

Surprising.

Most of the time the braking in mine is regenerative, only below 5mph or so, iirc, or in very heavy braking, do pads touch disc.
It is the low speed performance on friction brakes only I was commenting on.

Infinitely better is quite a lot for a system rarely actually in use

I have no experience of plated discs and I’m sure Porsche wouldn’t use them if they weren’t good but I saw them as a cosmetic rather than performance item.

On a Formula 1 car Carbon brakes are definitely worse than cast iron in the wet but usable. They are similar in dry conditions but much lighter and easier to keep “in the window” without damage So now ubiquitous

 

[Sidicks]

I also have not had any real problems with very wet brakes in thunderstorms. There is the same initial cleaning as in other cars needed. The large 410 mm PSCB with 10 pot calipers need some extra initial pressure to clean but after that they are good.

I think Porsche test their brakes before model release and they all have great stopping power. I think the test included limited or no fading after 25 stops from something like 80% Vmax to 40 km/h or similar.

Stopping distances could be more dependent on tyres than brakes I assume?

PSCBs are 6 piston calliper at the front (4 at the rear), same as the standard brakes on the GTS.

 

[Scandinavian]

PSCBs are 6 piston calliper at the front (4 at the rear), same as the standard brakes on the GTS.

No not for the MY 2020. They are massive 10 pot front and 4 pot at rear. I think they change this in 2022?? See picture below
Not sure that more is better though??

 

[Sidicks]

No not for the MY 2020. They are massive 10 pot front and 4 pot at rear. I think they change this in 2022?? See picture below
Not sure that more is better though??

Ah, ok. Those were used for the 911 Turbo S I think? They certainly had 10-pot calipers on the 992 Turbo S for PCCB.

 

[W1NGE]

Porsche don’t claim any stopping benefits of the PSCB compared to the standard brakes, only shinier, less corrosion, less brake dust and increased longevity. Any greater stopping benefits will simply due to the increased size of the PSCB discs (410mm at the front), although the standard discs on the GTS (360mm) are already bigger than the discs on the 4S etc. Given Porsche’s reputation with brakes, personally I’m not convinced that the standard set-up was not up to the job in day-to-day use.



I’m sure I remember reading about this on my 997 C4S - if the system senses you suddenly lifting off the throttle, it automatically applies just enough pressure on the brake disc to clean it of any residual water, ready for any actual braking needed.

Believe me, they feel totally different. Not debating distance reduction - didn't suggest otherwise.

Put it this way - I would easily pass a blindfold test with standard 4S brakes vs any model with PSCB.

4S always felt spongy towards the end of the stopping manoeuvre and particularly doing slow speed stopping to a standstill (and yes, I had the brakes check and serviced) where the pedal often needed to be pressed further than imagined.

 

[W1NGE]

Surprising.

Most of the time the braking in mine is regenerative, only below 5mph or so, iirc, or in very heavy braking, do pads touch disc.
It is the low speed performance on friction brakes only I was commenting on.

Infinitely better is quite a lot for a system rarely actually in use

I have no experience of plated discs and I’m sure Porsche wouldn’t use them if they weren’t good but I saw them as a cosmetic rather than performance item.

On a Formula 1 car Carbon brakes are definitely worse than cast iron in the wet but usable. They are similar in dry conditions but much lighter and easier to keep “in the window” without damage So now ubiquitous

First 725 miles I had no choice...in my space time continuum this feels infinitely superior

 

[Ross]

It’s first thing every morning that can be disconcerting.
My GTS with standard brakes consistently brakes WITHOUT Regen at the first red light at the end of a gentle downhill then before the sharp left at the bottom of a hill.
The third braking manoeuvre after 1.5 miles the regen kicks in.
On a wet day those first 2 braking events that skim the discs feel HUGELY different from braking with regen.

I am ready for it on the way to work.

But sometimes it catches me out if on a different journey.
If I leave home and the lights are with me I can join the motorway without using the brakes. This means the brakes sometimes don’t skim without regen until I hit traffic on the motorway or even, on a quiet day, until I actually leave the motorway!

It happened once in Birmingham on the M6 90 miles from home!

If the discs are wet too this braking event can really give a heart stopping moment as the normal mild pressure on the brake pedal can be entirely ineffective for the first second. Of course all you need is to give a good stamp on the brake to dry and skim and they work fine but it is very different from when the regen braking is working

 

[tchavei]

I seem to remember Merc introduced a system which when wet would automatically skim the rotors to keep them dry - simple genius really and not sure why everyone else didn't latch on to this.

I have this on my MB. It's a blessing but sometimes a curse if you don't go with oem brake pads.

When the system detects water, the brake pads are pushed closer to the rotors. It's very light. Just enough to clean the water film. Works splendid.

With non oem (or hard) brake pads you get a constant, irritating whining during rain.

I know because about 6 years ago I was 600km from home and the brake worn pad warning light came on. Wife refused to return home with the light on (there was plenty of material left) so had to drive to a supermarket auto shop on a Saturday to have the brakes replaced to return home.

Needless to say, I had to swap the brake pads after a week with rain as I couldn't stand the whining.

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