[Bostro]

Hey,

So the issue of the G8x with their small rear brakes has been confirmed by me.

12k miles. Hearing the metal noise from the rear right side. Checking the service status and see info 2000mils till breaks exchange.

Next day issue is even bigger, breaking and noise is very obiouse. By the time I reached BMW (12miles) my foreman already saw rotors scraped, ugh so bad looking :-(

Conclusion: full rear brakes need replacement including the rotors. Left the car, should be ready by tomorrow evening. Accelerated repair and because of safety concern i was not allowed to take the car back. Was give IX .

Question: why sensors did not catch it? Answear: Because sensor is placed in the middle of the rotor and my pads reached its limit on outside section. Buuuu….. Will do pictures tomorrow if I have a chance to see old parts. (Update, forgot to take pictures)

Learning: just in case lets better check pads visuallu from time to time. Not just trust sensors especially if you track the car.

$$$: zero. All covered by BMW :-) maitenance plan :-)

Loaner: bmw IX50. More dynamic then expected, and way way way heavier then expected. Turning and braking scared me so much… I needed few miles to recalibrate my late braking and hard turning

[Needsdecaf]

Jesus, how much are you getting into the traction control? Is your car RWD?

[Bostro]

Originally Posted by Needsdecaf

Jesus, how much are you getting into the traction control? Is your car RWD?

Xdrive :-)

I will not say that Im totally crazy driver but for sure if I can, i drive the car as the M-car.
I should add, I had 2x si gle track days. But even then… we are all surprised how quickly backs wear out.

If Im driving in Comfort, its comfort driving also. When im pushing, 90% of a time in MDM mode.

[Gatti-man]

Track days destroy brakes. That’s the issue.

[Hoovzz777]

My rear breaks just went out too at 11k miles. I thought these cars most of the breaking is done by the fronts. I still have little less than 50% on my front pads but the rears are gone.

[Needsdecaf]

Originally Posted by Hoovzz777

My rear breaks just went out too at 11k miles. I thought these cars most of the breaking is done by the fronts. I still have little less than 50% on my front pads but the rears are gone.

Traction control uses the rear brakes (not breaks).

[Boomer 2019]

I have been doing this for over 2 years now.

Track driving these cars will result in the rear pads vanishing very quickly. This is not a function of TC; DSC; MDM; X Drive or any other nanny acronym you can think of. It will happen with everything turned on, and with everything turned off with seemingly no difference in how quickly they wear away. It is all about physics. When you put that much friction and heat into an undersized brake pad it cannot dissipate the heat sufficiently, and the result is rapid degradation of the pad material. The reason the front pads last much longer when they are made of the same material is that they are more than twice the size of the rears. Physics.

About a year and a half ago I switched to full on race pads. The wear increased greatly and I am very pleased with the results, but you know what? The small rears still wear down much faster than the larger fronts. Physics.

Even if you don't track your car you will still be subject to a much shorter lifespan of the rear pads than on previous M cars. They had larger pads. Physics.

But cheer up. AP Racing Brakes has come up with their Radi-CAL Competition Brake kits (front & rear) for the G80/82 with properly sized rear calipers. Shouldn't be much more than about $12,000 and problem solved.

[Needsdecaf]

Originally Posted by Boomer 2019

Shouldn't be much more than about $12,000 and problem solved.

I can replace a lot of those tiny rear pads for $12k!

[Boomer 2019]

Me too. Although the AP's do offer some major bling factor over my charcoal briquet rear calipers. Going to work out to about 34 sets of rears for me. That's a bit over 200 track days. Hell.. I won't keep the car that long.

[Needsdecaf]

Originally Posted by Boomer 2019

charcoal briquet rear calipers.

Truth!