Originally Posted By: CBR.worm
Unfortunately it seems that many run of the mill braking systems can handle one emergency stop from highway speeds. They perform their function and need to be replaced.
A few months ago I was in a rental chevy (malibu?) in Atlanta. Traffic was moving about 85-90. I watched a pile up in front of me, looked in my mirror and hammered the brakes. I slowed down to about 15 and went around the crash. The brakes were badly warped and every stop after that felt like the car was going to shake apart. The car had 11k miles on it. That was after one fast stop.
I do track days with my car and have upgraded the pads rotors fluid and lines, I can scrub off speed from well over 100 down to 60 a few times without ruining them, but that is about the limit without going to oversize components. I have to be slow on the straights and smooth into the corners to keep from cooking my 'sporty' cars brakes.
That's....sad, and one of the several reasons I dislike North American cars (a sweeping generalization, I know). I recall an article in print I read which quoted a senior engineering member from one of the domestic brands: "They design theirs to go 155 and we design ours for 55 - which do you think will end up better?". The same goes for stopping. Off topic, I digress...
It's worth nothing that you never know how a rental was treated. A lot of brake judder/shudder/pulsing isn't warping but deposit problems. Some may wish to read
http://www.zeckhausen.com/avoiding_brake_judder.htm for some comments on that.
My "sporty" 1990 Integra could get the brakes to the point of smoke trails and not have any problems after cooling when using OE parts. I had a 1992 Porsche 968 on which I couldn't even get the brakes to smell on the street - I did repeated 75mph-10mph cycles out in the country about 15 times and gave up. On a track day there wasn't much smell but there was enough heat cycling that the brakes re-bedded and performed noticeably better for the next 6-9 months or so. On my "sporty" 1998 BMW 528 I can get them smelly after a number of stops but they've never faded or begun to vibrate on me.
While on the go I'm aware of many vehicles carrying similar or higher weight than my 528 with significantly smaller braking systems. My 5er doesn't exactly have huge brakes to begin with but it's no wonder there are issues with some of the tiny braking equipment considered "sufficient" that's rolling off of the assembly lines today.