[Rbrown]

I have 22k miles on my M40i.

Brake pads "look" ok. When are people changing them to avoid any damage to the disks?

Also, any recommended brands to replace them?

Thanks in advance.

[ga9213]

Changed at 40k miles. I went with DFC Euro Ceramic and overall mostly happy. They are quiet and after initial bedding they had great bite. As my wife has been driving I've noticed the pads don't have the bite they did unless I occasionally do a hard brake session to put down some material on the rotors again. Then bite is back. Dusting remains low.

[titomi]

I've got 54k km on the odometer and it is asking for change (rears only). Still thinking whether leave that to the dealer or take it someplace else.

[Ravenous666]

You will get a warning when they are due. There is a sensor wire embedded in the pad which triggers the warning when grind down. Usually you are good to go for 2000km then.

If you want an alternative to the BMW OEM pads, I would go for Brembo P 06 099

And you need a new wear sensor: Febi Billstein 170747 or BMW 34356870351

[Rbrown]

Thanks for all the feedback.

Looks like there is still a bit of life in them. 👍

[kevinkay]

Originally Posted by Rbrown

When are people changing them to avoid any damage to the disks?

Did anyone reuse the rotors? had them turned down?

[spangle1980]

Yo peeps.

Thought I'd latch onto this thread rather than creating another. Glad I did because of this statement

"You will get a warning when they are due. There is a sensor wire embedded in the pad which triggers the warning when grind down"

So - I believe the brakes go initially off of mile/km based warning. I know this because I'm nosey and keep an eye on things. For the past few months I've been watching the count of miles go down, and finally it reach 1200miles today and gave an alert to say change those pads. However ...

1, I tend to drive in anticipation, so brakes a last resort - i.e. they should wear down less than Joe Public
2, this mileage count is most probably like the one in previous gen, i.e. a collective estimation based on what someone in Germany thinks is likely; so essentially a waste of time

but more importantly

3, Based on the above, i.e. the warning now is of an ignorant computer as to what is reality, when and in what form does an alert come for "I hit the wear sensor dude"

Oh, and the icing on the cake, anyone in UK had rear pads done and how much did it cost?

[Goldiegee]

I read on another group that if you have the driver assistant package, your rears wear out quickly as the system uses them in the ACC.

[spangle1980]

Originally Posted by Goldiegee

I read on another group that if you have the driver assistant package, your rears wear out quickly as the system uses them in the ACC.

Fair point - but I never use it :-)

[titomi]

My warning is on for about 2 months now, initially said 2000km to go, now it's 800 a today it was checked and I was told the pads have 5mm. So I guess it's pretty accurate.

[Goldiegee]

Originally Posted by spangle1980

Fair point - but I never use it :-)

How many miles have you done?

[MediaMan]

Originally Posted by spangle1980

Yo peeps.


Oh, and the icing on the cake, anyone in UK had rear pads done and how much did it cost?

I have a late 2017 G01 car, and the BMW app says rear pad service is £198 at my local East Midlands dealer. £456 with disks.

Not sure what an indie would charge for the pukka stuff, rather than cheaper Mintex or EBC pads.

Fronts £298 pads only, £670 with discs. Ouch!

Oddly for a 3+ year old X3, brake fluid replacement is £52, yet for wife's Cooper S (2020 reg), the cost would be just over £100. 🤷*♂️

[Raphael X4]

Originally Posted by kevinkay

Did anyone reuse the rotors? had them turned down?

I would like to know this too.

I asked my dealer and they gave me a generic answer saying it's up to the mechanic but usually they just replace them.

I'm assuming they are made thicker so they can be machined.

[marcati]

I have 70k KM on my X4 and I've had brakes changed 3x times now. Rears go first, but my fronts are usually within 2k of the rears so I wait and do them together.

The above answers are correct. The sensors will give you a 2k KM heads-up

[spangle1980]

Originally Posted by Goldiegee

How many miles have you done?

44k - however I am fast but 'predictive' driver - i.e. give lots of room to avoid having to brake. I checked the pads and they're ample, so proves this mileage countdown is just a generic effort of a best guess based on typical driving profile.

Ironically it popped up with brake fluid service a few days later, so I'll get this confirmed when I can be arsed to get that done.

[kevinkay]

Originally Posted by spangle1980

44k - this mileage countdown is just a generic effort of a best guess based on typical driving profile.

Im not sure your understanding the sensor.
When the pad wears down enough to allow the sensor to hit the rotor - the sensor gets ground down (ruined) and sends a signal that your pads are worn down.

[spangle1980]

Originally Posted by kevinkay

Im not sure your understanding the sensor.
When the pad wears down enough to allow the sensor to hit the rotor - the sensor gets ground down (ruined) and sends a signal that your pads are worn down.

I (believe) I understand it perfectly - welcome to be corrected though. The way BMW works (IMHO) is that on the iDrive, if you look, there is a countdown of miles where BMW believe a 'normal' driver will need new pads by. Let's have a thought experiment. The countdown is set at 45 000miles. You drive 30 000 miles and then it reads "replace brake in 15 000". Another 5 000 and it's "10 000" on it goes till it gets to about 4 ish and then you get a 'hey dude maybe it's time to replace your brakes".

Let's continue this thought experiment with a driver in a country with no cars. He/She drives around at ease, and hardly ever uses the brakes, hey there's no need because there is no-one else around (perhaps a good sci-fi film here :-). So that person hasn't used the brakes (or rarely) yet the computer is still merrily counting down.

Another experiment. A driver that hammers the anchors at every opportunity - rides those brakes. When they hit 10 000 (even though the computer is still saying 35 000 left), they hit the wear sensor since they've been riding those brakes HARD.

So my proposition is that there are two different systems in play. One is the iDrive which has an estimate of when they'll fail, the other is the binary sensor which, when hit, flags a different kind of alert. That's my position, but I wholly accept anyone to flame this.

Thus, due to my driving style (and visual inspection of the pads) I believe I am good for at least another 10-15k, even though the computer is telling me it's time for a change.

[titomi]

Originally Posted by spangle1980

I (believe) I understand it perfectly - welcome to be corrected though. The way BMW works (IMHO) is that on the iDrive, if you look, there is a countdown of miles where BMW believe a 'normal' driver will need new pads by. Let's have a thought experiment. The countdown is set at 45 000miles. You drive 30 000 miles and then it reads "replace brake in 15 000". Another 5 000 and it's "10 000" on it goes till it gets to about 4 ish and then you get a 'hey dude maybe it's time to replace your brakes".

Let's continue this thought experiment with a driver in a country with no cars. He/She drives around at ease, and hardly ever uses the brakes, hey there's no need because there is no-one else around (perhaps a good sci-fi film here :-). So that person hasn't used the brakes (or rarely) yet the computer is still merrily counting down.

Another experiment. A driver that hammers the anchors at every opportunity - rides those brakes. When they hit 10 000 (even though the computer is still saying 35 000 left), they hit the wear sensor since they've been riding those brakes HARD.

So my proposition is that there are two different systems in play. One is the iDrive which has an estimate of when they'll fail, the other is the binary sensor which, when hit, flags a different kind of alert. That's my position, but I wholly accept anyone to flame this.

Thus, due to my driving style (and visual inspection of the pads) I believe I am good for at least another 10-15k, even though the computer is telling me it's time for a change.

What kind of alert do you think the brake sensor will trigger? Different than the countdown?

[Wgosma]

Originally Posted by Raphael X4

I would like to know this too.

I asked my dealer and they gave me a generic answer saying it's up to the mechanic but usually they just replace them.

I'm assuming they are made thicker so they can be machined.

rotor thickness should be measured, if measures at or above the minimum thickness info which is stamped on the rotor hub one is fine with continuing to use the rotors and replace pads only. only case where rotors should be replaced is if they measure below min thickness or surfaces are marred, not flat/running true, which would generally be noticed by the driver as uneven braking action.....this is not a common occurrence.

[Wgosma]

Originally Posted by titomi

What kind of alert do you think the brake sensor will trigger? Different than the countdown?

There is a brake symbol that lights up on the dashboard once the wear sensor is triggered, that warning lamp will not be extinguished until a new pad sensor is refitted, along with new pads- look in your car's owners manual - it will be explained.

[Raphael X4]

Originally Posted by Wgosma

rotor thickness should be measured, if measures at or above the minimum thickness info which is stamped on the rotor hub one is fine with continuing to use the rotors and replace pads only. only case where rotors should be replaced is if they measure below min thickness or surfaces are marred, not flat/running true, which would generally be noticed by the driver as uneven braking action.....this is not a common occurrence.

I understand that.

My question really is does BMW manufacture the rotors thicker than their minimum requirement so they can be resurfaced.
Or does BMW purposely manufacture rotors at the minimum thickness in order to make extra money on having rotors always replaced?

[Wgosma]

Originally Posted by Raphael X4

I understand that.

My question really is does BMW manufacture the rotors thicker than their minimum requirement so they can be resurfaced.
Or does BMW purposely manufacture rotors at the minimum thickness in order to make extra money on having rotors always replaced?

Their new rotors are above minimum thickness, I do my own brake work for 15 years on these cars so there is definitely more meat there on a new rotor.
I typically get at least one and more typically 2 pad changes before rotors are below spec. Thickness.