[Bimma360]

Originally Posted by Mnfamilyguy2020

This has become a fairly hot issue that seems to be colored by quite a bit of conformation bias, if you want to make a change/upgrade to your brakes, that's great! Do it!

But, now it looks like someone has flagged Bima360 as propagating SPAM which is not so great in my humble opinion. I have nothing to do w/Bima360 and I see absolutely NO spam coming from him/her. I've clicked "looks ok" on all the pink dialogue boxes that are now attached to his posts....

AGAIN!? Are you fucking kidding me? Hahaha. This has happened to me 3 times already. And an admin Jason had to restore my account already. The PM function is still broken for me.

Haha whoever did it this time has got to be the biggest tool on this forum. What a Karen.

[blau3er]

Originally Posted by Kevin_The_Clean1

With brake pads close to double in size, it's no wonder the amount of friction & bite is increased. Twice the surface area is a substantial gain. You can do all the calculations you need to on paper, do hours of HW & discuss this subject matter in nauseum. Many of those who continue to critique the 6-piston units & yet continue to complain about the 4-piston units at the same time make me laugh. I too want to be extra convinced before I buy things. But some purchases are a clear no brainer in my book. Not only are these 6-piston calipers more rigid (a true mono-block) instead of the two clam-shells bolted together, but they're also 1-2 pound lighter as well. I for one love them & wouldn't ever want to go back.

Agreed - like wading through sand!

If you wanted a full OEM+ upgrade, just fit the 380mm rear discs & calipers from F95 and then you've got the complete kit with no issues to worry about.

[Th3Walrus]

Originally Posted by Kevin_The_Clean1

With brake pads close to double in size, it's no wonder the amount of friction & bite is increased.

That's not how it works. Ignore going from 4 pot to 6 pot for a second. If you were able to install the bigger area X5M pads into the X3M 4 pot caliper, the bite would be the same, as the caliper pistons are still outputting the same clamping force. The increase in friction area is equally offset by the force now being distributed over a larger surface area.

6 pot calipers keep the pad flatter on the rotor, reducing pad taper. Also as previously mentioned, it spreads the heat over a larger area for better heat dissipation for repeated hard braking on the track. But for it to increase bite, the total area of the 6 pistons would need to be greater than the total area of the 4 pistons.

[Bimma360]

Originally Posted by Th3Walrus

That's not how it works. Ignore going from 4 pot to 6 pot for a second. If you were able to install the bigger area X5M pads into the X3M 4 pot caliper, the bite would be the same, as the caliper pistons are still outputting the same clamping force. The increase in friction area is equally offset by the force now being distributed over a larger surface area.

6 pot calipers keep the pad flatter on the rotor, reducing pad taper. Also as previously mentioned, it spreads the heat over a larger area for better heat dissipation for repeated hard braking on the track. But for it to increase bite, the total area of the 6 pistons would need to be greater than the total area of the 4 pistons.

Exactly, and let's take this one step further.

Friction Force, aka "Stopping Power", aka "bite" is a result of pad CoF and the force perpendicular to the back of the brake pads. What's the force perpendicular to the back of the brake pads? Caliper Clamping Force. What is caliper clamping force? Piston area x line pressure.

Therefore a change in caliper with a reduction in piston area, results in a caliper with a reduction in clamping force, which actually results in reduction of Friction Force or "bite."

Both pads are GG rated and have the same CoF. That's a constant variable.

[Th3Walrus]

What is the diameter of the front X3M 4 pot and the X5M 6 pot pistons?

[Bimma360]

I put them together in this thread.

https://x3.xbimmers.com/forums/showthread.php?t=2072977

[Th3Walrus]

Originally Posted by Bimma360

I put them together in this thread.

https://x3.xbimmers.com/forums/showthread.php?t=2072977

Ah so they are smaller diameters on the leading edge of the pad to reduce pad taper.

[blau3er]

Originally Posted by Bimma360

I put them together in this thread.

https://x3.xbimmers.com/forums/showthread.php?t=2072977

You should update this with the correct size discs for the rear of F95 X5M, which is 380 x 28mm.

Additionally, G8x M2, M3 & M4 do not use 395mm front discs with the 6 piston calipers. Instead, they use 380 x 36mm and as such also have a smaller brake pad height to suit - the friction surface of the G8x pad is 77mm tall.

Hope this helps!

[Bimma360]

Originally Posted by blau3er

You should update this with the correct size discs for the rear of F95 X5M, which is 380 x 28mm.

Additionally, G8x M2, M3 & M4 do not use 395mm front discs with the 6 piston calipers. Instead, they use 380 x 36mm and as such also have a smaller brake pad height to suit - the friction surface of the G8x pad is 77mm tall.

Hope this helps!

It does. But to clarify, the numbers in the chart don't list any rotors for cars outside of the F97, except for the hypothetical ones. The rear 370mm rotor you are seeing in there is for the stock rear F97. Same for the front rotors. I think you are probably just getting confused with the way I am labeling the first column.

[Kevin_The_Clean1]

I knew the brake system experts were just around the corner & it was only a matter of time before they gave us all a small classroom session. LOL I for one, prefer a caliper & pad that will allow me to drive me X3 M harder for substantially longer periods of time. And are much more stout / robust units from the ground up. The fact that there's less pad taper is also a big plus. From the moment they were installed the feedback & increase in responsiveness to small inputs, are exactly what someone who wants to take their 4,600 lb monster to the next level. If the 4-pot calipers "some" of you guys are still praising & touting for all eternity are such great units, why aren't they used to stop the M2, M3, M4, M5, M8, X5 M & X6 M... ?

Oh that's right, the 6-piston units are far superior to the measly 4-pot calipers in every regard when they get warm to hot & are subjected to highly spirited driving. For the street, the smaller calipers are "okay" & decent enough to get the job done. But at the end of the day, do you want to continue using something that was a cost saving measure to begin with... ? I certainly don't. Do all the math & calculations you want. Then come back & continue to show us the data you've collected. Some of us like to actually drive cars in the real world & realize that badass machines are often times much better on the road then they are on paper.

It's ultimately your decision & choice. I'm sure in another year we'll still have tons of people straddling the fence, arguing the 4-pot units are still the best for the F97 X3M. As people begin to add more power to their F97's, the desire for a more robust breaking system will only increase. It again, was simply a cost cutting maneuver & it's funny that none of the experts crunching the numbers are taking that into consideration. If they are, they're denying to simply admit that. Why are cars that are substantially lighter then the F97 not using the 4-pots... ? To keep the F97's costs down, the M team figured there would be no additional benefit by making them standard issue. But they didn't fully understand this niche high performance SAV market & the type of people buying them. Little did they know, a great deal of us like to push this platform to it's limits & enjoy bolting things to increase it's potential.

Again, I'm not (at any point in time) taking a step backwards & installing the heavy 2-piece 4-pot calipers with their wimpy little (Ford truck like) pads -FOR- my light weight mono-block 6-pot units with a substantially lighter pad. And that front to rear bias change, do any of you REALLY think you're going to notice less than 2% difference... ? Come on guys, lets change the narrative here. Just a touch, shall we...

[Bimma360]

Originally Posted by Kevin_The_Clean1

I was under the impression that overall clamping force (applied by the caliper) & the bite from the specific CoF (provided by the pad) were two different things... ?

I am sorry I don’t know what you are asking exactly, that the quote doesn’t answer.

[Bimma360]

Hahaha wow.

[Th3Walrus]

Originally Posted by Kevin_The_Clean1

I knew the brake system experts were just around the corner & it was only a matter of time before they gave us all a small classroom session.

We aren't bashing what you did, we're just pointing out that the 6-pot calipers don't increase the clamping force. You're getting bent out of shape for no reason and taking our input the wrong way. I even said they will improve heat dissipation for repeated hard braking. I have no doubt they improved the brake feel as well.

[TacosRule!]

Originally Posted by Th3Walrus

That's not how it works. Ignore going from 4 pot to 6 pot for a second. If you were able to install the bigger area X5M pads into the X3M 4 pot caliper, the bite would be the same, as the caliper pistons are still outputting the same clamping force. The increase in friction area is equally offset by the force now being distributed over a larger surface area.

6 pot calipers keep the pad flatter on the rotor, reducing pad taper. Also as previously mentioned, it spreads the heat over a larger area for better heat dissipation for repeated hard braking on the track. But for it to increase bite, the total area of the 6 pistons would need to be greater than the total area of the 4 pistons.

Just spitballin' here, how much of an effort would it be then to install the 400+mm rotors from the F95? I really dont feel like paying $5K+ for the 415mm aftermarket kit, law of diminishing returns and all...

Bigger rotors, bigger calipers (more pistons) with bigger pads, oem BBK

[Th3Walrus]

Originally Posted by TacosRule!

Just spitballin' here, how much of an effort would it be then to install the 400+mm rotors from the F95? I really dont feel like paying $5K+ for the 415mm aftermarket kit, law of diminishing returns and all...

Bigger rotors, bigger calipers (more pistons) with bigger pads, oem BBK

F95 and F97 are the same 395mm front rotors, where are you getting 400mm from? Do you mean F10 M5?

[TacosRule!]

Originally Posted by Th3Walrus

F95 and F97 are the same 395mm front rotors, where are you getting 400mm from? Do you mean F10 M5?

Yeah sorry, M5.

[Kevin_The_Clean1]

Originally Posted by Th3Walrus

We aren't bashing what you did, we're just pointing out that the 6-pot calipers don't increase the clamping force. You're getting bent out of shape for no reason and taking our input the wrong way. I even said they will improve heat dissipation for repeated hard braking. I have no doubt they improved the brake feel as well.

Thank you for wording it this way man. Just seems as if every time I enter this discussion I'm getting a full classroom session full of calculations on paper. But enjoying your car doesn't exist in number crunching on paper. In my experience from the driver's seat the X3 MC I own now performs better "for me" on the street & track. Once some highly spirited driving is done & you've saturated the brake system with some substantially nice toasty temps (which is easily done in an effortlessly short amount of time) is where these 6-piston units really shine & come into play.

Sure, I've reduced the diameter of the total piston area by 5%. Wow. You're going to tell me you can actually feel this in day to day situations. Ok. And I've moved the front to rear bias by 2%. Again, wow fellas, BFD. On paper these may seem big to you, but in the real world they don't mean much. Not to me anyway. Trying taking your F97's off the city streets for a little while & try driving them close to their full potential -or- right at their limits for a period of time on a track. That's why the M team built this S58 test bed chassis to begin with. Right? Because it's track capable SAV that's agile, nimble & very dynamic. I'll stop defending my position because I no longer feel the need to.

I have improved my X3 MC to my liking & for the type of driving I like to often do. I can now modulate the brakes with a greater degree of precision, get more linear pedal feedback, have experienced much more consistency in a greater range of operating temps, have a lighter / more robust mono-block design & can hammer these down when they're toasty & I might have overcooked a corner / tight bend just a touch. Many people on the street will never push their stock brakes hard enough to experience the benefits of the OEM 6-piston units. That's fine, you do what suits you.

But again guys & gals, why does the M2, M3, M4, M5, M8, X5 M & X6 M ALL use this VERY SAME 6-PISTON OEM BREMBO CALIPER if it wasn't a better unit to begin with... ? That's the one thing I still don't get & will NEVER understand. Please draft up your best calculations & let the words smiths devise something that sounds great. Sorry for my rant. For all my needs, wants, desires & ultimate driving pleasure... I feel the X3 MC that "I own" should've been built with these calipers. My apologies for calling it an upgrade. Even though it may not seem like one to you, it still is to ME. So we'll call it a conversion to make all the brake experts & mathematicians happy here. And not offend anyone. The moment I began to refer to it as an upgrade is when the dialogue got a touch heated. LOL

One thing is for damn sure though... The 6-piston calipers sure look a whole lot beefier, more stout & purpose built. But then again, beauty is in the eyes of the beholder & it all depends on who you're asking because looks are subjective. I have a feeling that someone will say that's not true as well. I'm not just highly confident, I almost 100% sure without a doubt it will happen & be confronted head on. Oh well. At the end of the day, enjoy your machines & do what's best for you.

[Bimma360]

Originally Posted by Kevin_The_Clean1

Just seems as if every time I enter this discussion I'm getting a full classroom session full of calculations on paper. But enjoying your car doesn't exist in number crunching on paper.

Why enter the conversation then? It seems to me that if you are not interested in discussing calculations on paper, you shouldn't be inserting yourself in a conversation about calculations on paper.

Enjoying YOUR car might not exist in number crunching on paper, but perhaps others enjoy their cars differently than you.

Have some forum etiquette. I haven't posted any of this stuff in your brake thread. Which is why I created my own, and you proceeded to derail it almost immediately.

[TacosRule!]

Originally Posted by Bimma360

Have some forum etiquette.

Says the guy calls everyone a karen and then bitches like one about it.
There's a reason your posts get marked as spam. Your previous post is an example of this.


Ironic isnt it?

[Bimma360]

Originally Posted by TacosRule!

Says the guy calls everyone a karen and then bitches like one about it.
There's a reason your posts get marked as spam. Your previous post is an example of this.


Ironic isnt it?

You serious dude, hahah? I call everyone a Karen, not just the person abusing the spam feature?

Do you not get your own circular logic here?

[Kevin_The_Clean1]

Originally Posted by Bimma360

Why enter the conversation then? It seems to me that if you are not interested in discussing calculations on paper, you shouldn't be inserting yourself in a conversation about calculations on paper.

Enjoying YOUR car might not exist in number crunching on paper, but perhaps others enjoy their cars differently than you.

Have some forum etiquette. I haven't posted any of this stuff in your brake thread. Which is why I created my own, and you proceeded to derail it almost immediately.

I never knew that someone who was simply speaking their mind wasn't adhering to forum etiquette. So my apologies for violating this unwritten but assumed rule I'm being presented with now. Never meant to upset you or step on anyone's toes. Not exactly sure where this conversation is headed & how to even respond at the moment. But since we're here now, we might as well make the most of it. Right? You & another "brake expert" said this caliper change is not considered an upgrade based off your calculations. And that's fine with me that you two think this way. I for one won't let what others think effect my decisions in any way. Therefore, continue to present as many calculations as you both would like & need to.

We'll continue to discuss the nitty gritty details about a percentage point here & there a bit longer I can only assume. You've made it crystal clear that this is not an upgrade in your mind, again... based off calculations you fellas made on paper. Which is fine. It's good to do that, sometimes. Despite the way "some" of you guys may view this awesome plug-n-play component swap, it is an upgrade to me, in my eyes, in my mind & in the way the car responds to this stout mono-block. This BREMBO caliper was built for BMW & is exclusively bolted onto every new M2, M3, M4, M5, M8, X5 M & X6M. The fact that it's currently used in 7 of BMW's most potent product lines speaks for itself. Doesn't this alone speak volumes & reveal a plethora about this calipers overall effectiveness in terms of how capable it is... ?

Before I drive a highly potent machine, strike up a conversation with a pretty woman that many think is way out of my league, apply for a job that I may not fully qualify for "on paper" alone, I go for it & don't look back. When it comes to finances & certain big purchases, I do heavy calculations. But most of my life, I don't do calculations & try to talk myself out of things before they ever begin to unfold. "On paper" a percentage point here or there isn't a BFD. If the 4-pots were such great units, why doesn't the M2, M3, M4, M5, M8, X5M & X6M have them... ? If the total brake piston service area decreased that much & the front to rear bias also changed so much, why aren't heavily modified X3 MC's that are seeing heavy track use complaining & bitching about this stuff... ?

[Bee Pee]

Originally Posted by Kevin_The_Clean1

I never knew that someone who was simply speaking their mind wasn't adhering to forum etiquette. So my apologies for violating this unwritten but assumed rule I'm being presented with now. Never meant to upset you or step on anyone's toes. Not exactly sure where this conversation is headed & how to even respond at the moment. But since we're here now, we might as well make the most of it. Right? You & another "brake expert" said this caliper change is not considered an upgrade based off your calculations. And that's fine with me that you two think this way. I for one won't let what others think effect my decisions in any way. Therefore, continue to present as many calculations as you both would like & need to.

We'll continue to discuss the nitty gritty details about a percentage point here & there a bit longer I can only assume. You've made it crystal clear that this is not an upgrade in your mind, again... based off calculations you fellas made on paper. Which is fine. It's good to do that, sometimes. Despite the way "some" of you guys may view this awesome plug-n-play component swap, it is an upgrade to me, in my eyes, in my mind & in the way the car responds to this stout mono-block. This BREMBO caliper was built for BMW & is exclusively bolted onto every new M2, M3, M4, M5, M8, X5 M & X6M. The fact that it's currently used in 7 of BMW's most potent product lines speaks for itself. Doesn't this alone speak volumes & reveal a plethora about this calipers overall effectiveness in terms of how capable it is... ?

Before I drive a highly potent machine, [...]

KTC - FWIW I’m trying to deconstruct your sound reasoning and integrity of your 1st hand experience to avoid throwing more fettling funds to upgrade front anchors 😂😂😂😂