Pad deposite vs warped rotor

[m3f80sf2ny]

I have read a lot of comments about the true cause of brake vibration being pad deposits instead of warped rotors.

So my questions are:

1) In practice, how can one reliably distinguish between pad deposit from truly warped rotors? Supposedly pad deposits also result in thickness variation?

2) What kind of driving or other mechanical defect would cause rotors to warp?

[TRZ06]

Originally Posted by m3f80sf2ny

I have read a lot of comments about the true cause of brake vibration being pad deposits instead of warped rotors.

So my questions are:

1) In practice, how can one reliably distinguish between pad deposit from truly warped rotors? Supposedly pad deposits also result in thickness variation?

2) What kind of driving or other mechanical defect would cause rotors to warp?

I don't know, but I'm super pissed at BMW for f@cking up the steel brakes on this car.


They did it right in the E90/92, those were the best stock brakes I have ever had on a car. They were rock solid with no issues and grip for days.

Maybe they dumbed down the F80/82 brakes because of the CCB option, I don't know, but they used to be awesome. Now they suck.

[CanAutM3]

Originally Posted by TRZ06

I don't know, but I'm super pissed at BMW for f@cking up the steel brakes on this car.


They did it right in the E90/92, those were the best stock brakes I have ever had on a car. They were rock solid with no issues and grip for days.

Maybe they dumbed down the F80/82 brakes because of the CCB option, I don't know, but they used to be awesome. Now they suck.

The brakes on the F8X are the best of any M3(4) thus far. I've owned an E46, an E92 and now an F82. All are/were tracked extensively (16~20 track days per season). I can attest the the brakes on the F8X are better than the ones I had on my previous ///Ms.

[CanAutM3]

The best and fastest way to find out if it is uneven pad deposit that is causing the shudder, is to install some abrasive pads for a few days to scrub the deposits off the rotors. If the shudder progressively goes away, then it is indeed pad deposit.

Just look at the size of those rotors. Imagine the stress needed to actually get them to warp. Maybe an intense thermal stress could warped them, such as splashing them with water when they are red hot. But even then...

[TRZ06]

Originally Posted by CanAutM3

The brakes on the F8X are the best of any M3(4) thus far. I've owned an E46, an E92 and now an F82. All are/were tracked extensively (16~20 track days per season). I can attest the the brakes on the F8X are better than the ones I had on my previous ///Ms.

I disagree. They muffed up the pad or rotor compound. They don't play nice together.

In the E90/92, they played very well together, no matter how hard you used them.

[m3f80sf2ny]

Originally Posted by CanAutM3

The best and fastest way to find out if it is uneven pad deposit that is causing the shudder, is to install some abrasive pads for a few days to scrub the deposits off the rotors. If the shudder progressively goes away, then it is indeed pad deposit.

I upgraded from OEM to DS2500, but apparently it wasn't enough to scrub off the deposits. I will be upgrading again to RS29 and hopefully that will be more effective.

[Jockey]

Originally Posted by TRZ06

I don't know, but I'm super pissed at BMW for f@cking up the steel brakes on this car.


They did it right in the E90/92, those were the best stock brakes I have ever had on a car. They were rock solid with no issues and grip for days.

Maybe they dumbed down the F80/82 brakes because of the CCB option, I don't know, but they used to be awesome. Now they suck.

Wow, you really have nothing good to say about this car.

You are also the only person I recall who thinks the brakes on the E9X were better than this iteration.

[TRZ06]

Originally Posted by Jockey

Wow, you really have nothing good to say about this car.

You are also the only person I recall who thinks the brakes on the E9X were better than this iteration.

I am just honest in my opinions. For the cost of this car and how's it's billed, I expect certain things to be done right.

The pad / rotor materials don't go well together, which causes groaning and vibrations.

The suspension has sloppy rebound and doesn't give confidence.

The chassis has poor traction and is undertired.

The traction control / stability control system is very weak and intrusive.

These are ALL things that should be a non-issue in a $80k+ M car. I think I have every right for its price point to be pissed.

I'm not saying I hate the car, but they messed up a lot of key things.

[Jockey]

Brakes, suspension, chassis, traction control. Gee, anything else.

[TRZ06]

Originally Posted by Jockey

Brakes, suspension, chassis, traction control. Gee, anything else.

No, that's it.

[hdubf80]

Originally Posted by Jockey

Brakes, suspension, chassis, traction control. Gee, anything else.

He's right tho. Especially for M division. I haven't heard these complaints with the c63's

[Jockey]

Originally Posted by hdubf80

He's right tho. Especially for M division. I haven't heard these complaints with the c63's

Well damn, the previous generations of M cars must've really been bad since this model is an improvement over them.

[TRZ06]

Originally Posted by Jockey

Well damn, the previous generations of M cars must've really been bad since this model is an improvement over them.

The competition wasn't as fierce with the last generation, so it was clearly the best choice back then, so expectations were lower.

Things have changed.

All the issues I noted, with the technology that's out there now, should not exist.

And the problem is, the money it costs to fix those issues, is not cheap to do.

It's still cheaper for me to fix those issues with aftermarket, then taking the deprecation hit and starting over, but still the point is I shouldn't have to spend the money in the aftermarket in the first place.

[Jockey]

I guess you should've gone for test drive then and all of these inadequacies would have presented themselves.

[Racer20]

Originally Posted by TRZ06

I don't know, but I'm super pissed at BMW for f@cking up the steel brakes on this car.


They did it right in the E90/92, those were the best stock brakes I have ever had on a car. They were rock solid with no issues and grip for days.

Maybe they dumbed down the F80/82 brakes because of the CCB option, I don't know, but they used to be awesome. Now they suck.

Are you joking? Why don't you sell it and buy another TT. You seem to hate everything about the F80.

[TRZ06]

Originally Posted by Racer20

Are you joking? Why don't you sell it and buy another TT. You seem to hate everything about the F80.

Don't get all but hurt.

I don't have money to burn to take the deprecation hit.

These are my opinions.

I don't hate the car, I just think BMW dropped the ball in a few key areas. And I have no problem pointing that out, call it constructive criticism

[Jockey]

Originally Posted by TRZ06

Don't get all but hurt.

I don't have money to burn to take the deprecation hit.

These are my opinions.

I don't hate the car, I just think BMW dropped the ball in a few key areas. And I have no problem pointing that out, call it constructive criticism

There is nothing constructive about your criticism, that's why you get called out on it.

[TRZ06]

Originally Posted by Jockey

I guess you should've gone for test drive then and all of these inadequacies would have presented themselves.

Ok Einstein...

Tell me, on a test drive how am I going to know that in 1000 miles the brake material doesn't work well together and causes vibrations.

How am I going to know that the traction/stability control is intrusive.

How am I going to know how the suspension is going to react to various conditions.


How am I going to know traction is going to hard to come by. All new tires are slick as they have the release mold on them still.

[hdubf80]

At some point bmw forgot to compete with the rest of the major brands and thought about just selling units. These issues aren't present with let's say ferarri because of the constant competition from lambo or other brands. BMW thought it would be the benchmark and would not be contested but unfortunately the other brands have stepped up their game and are knocking bmw out of the top spot. These aren't my opinions just the majority of the reviewers that publish articles. (i.e motor trend, carfaction, autocar, etc) I've started a thread on the break issue and bmw is aware and I heard changing the pads. I'm not qualified enough to talk about suspension and chassis but Cadillac has beat them there. And the DSC is terrible. It's either all or none. Even the c63's has them beat there. These are facts not just opinions. The comp pack should have been the original version and the ZCP even more competitive. We should never lose to a Cadillac smh.

[F3IGHTY]

Originally Posted by CanAutM3

The brakes on the F8X are the best of any M3(4) thus far. I've owned an E46, an E92 and now an F82. All are/were tracked extensively (16~20 track days per season). I can attest the the brakes on the F8X are better than the ones I had on my previous ///Ms.

I completely agree, I came from an track prep'd S2k with more tire than a F80, and the most aggressive pads from various manufacturers, running within a couple seconds of local track records for my class. I am very impressed with the stock F80 setup and its heat capacity straight from the factory. Of course its not perfect, and theres plenty of room for a more aggressive tire and pad, but the car is well equipped for a street car.

I've been reading people complaining about pedal travel too in other threads, this has much more to do with the brake master cylinder bore size and accompanying booster than the pad compound. Even if you slap on a gnarly pad, you'll still end up using the same amount of stroke for equivalent force. If you want the pedal to be rock hard at the top of the stroke, get a larger bore size, and don't complain about lack of modularity later.

Originally Posted by CanAutM3

The best and fastest way to find out if it is uneven pad deposit that is causing the shudder, is to install some abrasive pads for a few days to scrub the deposits off the rotors. If the shudder progressively goes away, then it is indeed pad deposit.

Just look at the size of those rotors. Imagine the stress needed to actually get them to warp. Maybe an intense thermal stress could warped them, such as splashing them with water when they are red hot. But even then...

Yup, to answer OP - "It's always pad deposits"

[m3f80sf2ny]

Originally Posted by F3IGHTY

Yup, to answer OP - "It's always pad deposits"

I am really hoping it's just pad deposits.

Last time the vibration didn't go away after 3 weeks of street driving. Then I went to track again so the wait will reset...