[upsidedownfunnel]

Originally Posted by Encanto

Imagine Brembo offering a 4-piston, electronic rear caliper replacement for this M3 (and for all BMW with the new electronic parking brake) as an aftermarket kit... that would be a hot seller. These sliding calipers are sh*t.

Imagine caring about such a minor detail. The rear brakes do not need fixed piston brakes. I understand they don't look as nice, but you would have to sacrifice weight by adding another fixed caliper in the back to "match" the front or a large solenoid on a fixed caliper. Some carmakers do those things but it's extra unnecessary weight (and cost). I'm not sticking up for BMW here, but does it really matter? I'd personally prefer a normal parking brake but there's no chance of that happening.

[upsidedownfunnel]

Originally Posted by MFNATIK

Definitely cost cutting measure to save beaucoup bucks. Sliders are adequate but when you're paying upwards of 80k, you expect more. Definitely disappointing.

It is and it isn't. The reason they went with it is the electronic parking brake. It's much easier to make an electronic parking brake that works with a floating caliper than one with a fixed caliper brake. This is because one solenoid can be used to actuate a floating caliper. On a fixed caliper, equal pressure must be applied on both sides of the brake and it's nearly impossible to put a solenoid on the outside of the brake (the wheel gets in the way). You can't rely on the hydraulics because the parking brake is also an emergency redundant braking system that must work without hydraulic pressure to be safe.

BMW did away with the bulky and heavy drum parking brake setup so that's no longer an option either. This is why up until recently, a lot of high end cars had TWO rear calipers. A floating caliper for the parking brake and a fixed caliper for the main brakes (basically for show). Technically even BMW had two calipers, you just couldn't see the drum brakes. Even some of the new fixed calipers that now support electronic parking brakes are just a fixed caliper brake and floating caliper welded together. They look kinda goofy, are heavy, and it's purely for aesthetics.

They are not necessary on an M car essentially so BMW did not put one in. So it is a cost cutting measure in that sense that they could put some exotic bit in. But it's not a cost cutting measure in that if they could just put a traditional fixed caliper brake they would, but they can't without adding a lot more cost.

[Boostedphil698]

Originally Posted by GregW / Oregon

I thought 4-piston fixed caliper front, 2-piston fixed caliper rear. This is them just after painting. Don’t think rears are one-piston sliding. Same calipers as these: https://www.ecstuning.com/b-genuine-...yABEgKnRPD_BwE

Yes, your M4 has 4 piston front fixed brakes and 2 piston rear fixed brakes. Your manual handbrake goes to a drum inside the rotor hat in the rear.

[MFNATIK]

Originally Posted by upsidedownfunnel

It is and it isn't. The reason they went with it is the electronic parking brake. It's much easier to make an electronic parking brake that works with a floating caliper than one with a fixed caliper brake. This is because one solenoid can be used to actuate a floating caliper. On a fixed caliper, equal pressure must be applied on both sides of the brake and it's nearly impossible to put a solenoid on the outside of the brake (the wheel gets in the way). You can't rely on the hydraulics because the parking brake is also an emergency redundant braking system that must work without hydraulic pressure to be safe.

BMW did away with the bulky and heavy drum parking brake setup so that's no longer an option either. This is why up until recently, a lot of high end cars had TWO rear calipers. A floating caliper for the parking brake and a fixed caliper for the main brakes (basically for show). Technically even BMW had two calipers, you just couldn't see the drum brakes. Even some of the new fixed calipers that now support electronic parking brakes are just a fixed caliper brake and floating caliper welded together. They look kinda goofy, are heavy, and it's purely for aesthetics.

They are not necessary on an M car essentially so BMW did not put one in. So it is a cost cutting measure in that sense that they could put some exotic bit in. But it's not a cost cutting measure in that if they could just put a traditional fixed caliper brake they would, but they can't without adding a lot more cost.

Thanks foe the detailed response. This is good to know. I wonder if BMW could have designed a caliper cover that would have made the rear brake match better with the front calipers. That would have probably been more aesthetically pleasing.

[Boostedphil698]

Originally Posted by MFNATIK

Thanks foe the detailed response. This is good to know. I wonder if BMW could have designed a caliper cover that would have made the rear brake match better with the front calipers. That would have probably been more aesthetically pleasing.

There are electronic parking brake fixed calipers, BMW just doesn't want to pay for it. Big rear brakes help with making the car squat more under load, instead of noise diving.

[kyrix1st]

Originally Posted by 435i_Phil

There are electronic parking brake fixed calipers, BMW just doesn't want to pay for it. Big rear brakes help with making the car squat more under load, instead of noise diving.

Nose diving has to do with front&rear brake bias (stopping force based on sum of surface area of piston(s)) rather than the size of the brake caliper. What multi-piston calipers excel in is stress management from heat. It is clearly a cost cutting measure nonetheless.

[MFNATIK]

Nonetheless, it’s a disappointment to me.

[Boostedphil698]

Originally Posted by MFNATIK

Nonetheless, it’s a disappointment to me.

I totally agree. It's all about minor details too.

[solstice]

Originally Posted by MFNATIK

Nonetheless, it’s a disappointment to me.

I’ll be disappointed if any of the following is true vs the F8X brakes:

- Longer stopping distance.
- Earlier onset and/or increased brake fade.
- Longer cool down time.
- Significantly shorter life span.

Aesthetically I don’t care about the calipers size or number of pistons. I do care about the rotors aesthetically though, small rotors inside large wheels is an eye sore and I like the look of drilled rotors.

[LOW4LYF]

Originally Posted by MFNATIK

Nonetheless, it’s a disappointment to me.

Why everyone is just about numbers? Most HP, biggest brakes etc.

With less HP and smaller brakes the Gx will still faster and stop better as any 800hp red eye hellcat with big ass brakes.

I don't care about the pistons on my rear calipers and I will buy the G8x, just sold my F82 ZCP.

[MFNATIK]

Originally Posted by solstice

I’ll be disappointed if any of the following is true vs the F8X brakes:

- Longer stopping distance.
- Earlier onset and/or increased brake fade.
- Longer cool down time.
- Significantly shorter life span.

Aesthetically I don’t care about the calipers size or number of pistons. I do care about the rotors aesthetically though, small rotors inside large wheels is an eye sore and I like the look of drilled rotors.

BMW gives up the fixed caliper to save a few lbs and justifies by saying it adds the convenience of an electronic handbrake. Seems like they're just cutting down on variances in production specs so they can re-use the off the shelf electronic brake from the G2X

[Boostedphil698]

Originally Posted by MFNATIK

BMW gives up the fixed caliper to save a few lbs and justifies by saying it adds the convenience of an electronic handbrake. Seems like they're just cutting down on variances in production specs so they can re-use the off the shelf electronic brake from the G2X

Hence cost cutting. Like, the C8 Corvette has a rear single piston caliper for the handbrake and i think a 4 piston rear setup for braking and it's less than the new G8x.

[mrrm3]

And, yet still continues to install beautiful Brembos on the rear axles of Boxsters, Caymans, 911s, etc.

BMW's decision to decontent the M3/M4 (with no better rear brakes than an an econo box) is a real disappointment to me. It is visually unappealing and just looks cheap.




Aesthetics are important. If they weren't, there wouldn't be so many outcrys about the grille.

[Boostedphil698]

Originally Posted by mrrm3

And, yet still continues to install beautiful Brembos on the rear axles of Boxsters, Caymans, 911s, etc.

BMW's decision to decontent the M3/M4 (with no better rear brakes than an an econo box) is a real disappointment to me. It is visually unappealing and just looks cheap.




Aesthetics are important. If they weren't, there wouldn't be so many outcrys about the grille.

Totally agree. I saw someone else complaining about the same thing on a Facebook article about the car. These cars aren't worth the money. The F Series is the best car and the G series will be a disappointment.

[hellokitty]

Originally Posted by 435i_Phil

Totally agree. I saw someone else complaining about the same thing on a Facebook article about the car. These cars aren't worth the money. The F Series is the best car and the G series will be a disappointment.

BMW's electronic brake implementation has been horrendous. My wife's car has them and it's probably the most annoying feature of the car. The button works half the time and it usually takes me two tries to get the brake to engage or disengage. A manual hand brake is so much better.

[brad850csi]

Originally Posted by hellokitty

BMW's electronic brake implementation has been horrendous. My wife's car has them and it's probably the most annoying feature of the car. The button works half the time and it usually takes me two tries to get the brake to engage or disengage. A manual hand brake is so much better.

I've never had a problem with having mine engage but about once a month I will think I've disengaged it then when I move off it is still engaged,

I've never driven a manual with a push button handbrake though and I must admit I'm worried about that a bit

[Boostedphil698]

Originally Posted by brad850csi

I've never had a problem with having mine engage but about once a month I will think I've disengaged it then when I move off it is still engaged,

I've never driven a manual with a push button handbrake though and I must admit I'm worried about that a bit

I don't understand why electronic parking brakes are even a thing.

[av.7447]

Originally Posted by 435i_Phil

I don't understand why electronic parking brakes are even a thing.

Don’t understand what people are discussing here to be honest but I will still add my thoughts on this very important subject. 😅 I have a habit of engaging the parking brake every time I park my car and I have never had any problems turning the electronic parking brake on or off. When bmw came up with it I thought or felt absolutely nothing about it... it works good, saves space, reduces weight and maintenance so in the end, who cares! As for the rear brake calipers, they are small, excellent! It’s a huge weight saving and they work better then they need to! Have you seen those huge unnecessary brakes on an M2 Comp. that add like half the M2’s weight? They just about add enough braking effect to compensate for their own weight gain and makes M2 overall heavier than M4. Porsche has better brakes? So go and buy a Porsche! I would anyways, if I would be slightly richer! Wouldn’t need to save money on a Bimmer... 😁

[lemetier]

Originally Posted by brad850csi

I've never had a problem with having mine engage but about once a month I will think I've disengaged it then when I move off it is still engaged,

I've never driven a manual with a push button handbrake though and I must admit I'm worried about that a bit

Does that usually happen with the beast sitting at an incline?

[solstice]

Originally Posted by lemetier

Does that usually happen with the beast sitting at an incline?

We have eBrake on our Cayenne and this is the only time it fail to work like clockwork. Parking in an incline and then reversing out of of the there. The eBrake on the Cayenne does in this scenario often get confused and applies the brakes again after the initial release on throttle. It takes a little wiggling to get going.

[naywa01]

Originally Posted by av.7447

I have a habit of engaging the parking brake every time I park my car and I have never had any problems turning the electronic parking brake on or off.

FWIW Here in the UK, at least when I was learning to drive, we are taught to engage the parking brake (BTW it always amuses me when I hear it referred to as an 'emergency' or 'e'-brake!). The instructor/examiner would pick up on it if it wasn't done, but maybe thats because historically our market has been predominately manual (or 'stick').

I also cringe when I see people parking their automatic tranmission car on TV/films, then they get out and I see the car rocking against the P-lock - no wonder people are always talking about getting a trans rebuild!!

My two cents on the nub of this debate; I'm not really too fussed, never tracked any of my cars and so I've found ABS (or ice!) to be the limiting factor in any hard braking I've ever done on the road

[lemetier]

Originally Posted by solstice

We have eBrake on our Cayenne and this is the only time it fail to work like clockwork. Parking in an incline and then reversing out of of the there. The eBrake on the Cayenne does in this scenario often get confused and applies the brakes again after the initial release on throttle. It takes a little wiggling to get going.

On the BMW DCT and F85/86, if the car is on a grade at startup and the parking brake is released before a gear is selected and it rolls against the transmission parking pawl, the parking brake will engage again.