Yet another brake "judder" question

[hesperus]

Sorry, new to 1M ownership.

Loving the car, but as others may have pointed out in the past, not the best high speed braking feel.

the car stops well enough for sure, i'm just not a fan of the sort of humming noise and slight sensation of vibration from the front brakes.

i'm only talking fast street driving, not track, so it's not really bad "judder", and is probably just pad deposits. i'm sure the rotors aren't warped (and yeah, i've read the StopTech article about cementite and all that.) Again, the car stops well, it's just a bit unpleasant to keep feeling that when braking from say 130-140mph.

maybe i'm spoiled coming from my other cars that are on ceramics.

what pads do people recommend to minimize this? i can put up with some squealing at low speed; that's probably preferable for me to the high speed slight "judder".

some pics from a recent run

[octainejunkee]

http://carbotech-europe.com/

I run carbotech xp12's on standard discs- i have an Alcon bbk with xp12's to fit at some point.
They are great from cold and work well on track- obviously the standard set up isnt great at coping with sustained heavy braking but these pads are the best option without going for a big brake kit.

link provided. Nice pic btw

[Ender_]

Carbotech XP series are not for the street, they sound awfully loud, I tried XP8's on the street, sounded like a bus.
Great on the track though...

[nachob]

My 2nd 1M had a little of this too. Not worth mentioning really but now that you did, I noticed it too. My first 1M, I bought new and didn't remember it but my second 1M had a little bit of it. The car was stored over the winter for long periods and apparently, there is some sort of buildup that happens just from storing. I got my pads and rotors replaced and it is smoother on breaking. Is this a car that sits for longer periods?

[hesperus]

I run XP8's or XP12's (not sure which, i think the 8's) on my C6 Z06 and they're pretty good. the car isn't a daily driver so i could probably put up with the squealing. i'm used to it from some of my other cars.

i was offered an Alcon BBK but the price was pretty crazy and i think is overkill for how i intend to drive this car (i.e., no track).

so bottom-line, is conventional wisdom that it's the stock BMW pads that are behind the juddeirng, and switching to more aggressive aftermarket pads will cure the problem?

[The Wind Breezes]

Simple, your pads weren't bedded in properly. Read about bed in procedure and make sure it's done properly (do it yourself) when you put in new pads and rotors. Factory spec rotors for under $200 are 100% OK and you won't notice any difference between them and the $800 / pair 2 piece rotors from ECS. It's 100% bling and a very slight reduction in unsprung weight.

The PADS are the most important thing, if you're not repeatedly slowing down from 140 several times in a row even factory pads would work. Just make sure to bed them in and you won't have this issue.

[hesperus]

Originally Posted by The Wind Breezes

Simple, your pads weren't bedded in properly

ok, i'm buying that.

the previous owner was not one to drive the car hard at all... that would explain it.

will try that first. thanks!

[The Wind Breezes]

Originally Posted by hesperus

ok, i'm buying that.

the previous owner was not one to drive the car hard at all... that would explain it.

will try that first. thanks!

You'll need fresh hardware to do the bedding in. It won't work when the pads and rotors have already mated.

[hesperus]

Originally Posted by The Wind Breezes

You'll need fresh hardware to do the bedding in. It won't work when the pads and rotors have already mated.

was thinking removing the rotors and pads and having both surfaces sanded down; not a reskim obviously, but just to take some of the material off.

though i suppose if cementite has already built up from hotspots, that wouldn't work... TIA!

[The Wind Breezes]

Probably won't work but if you try it report back.

Also curious, do you have any problems with the authorities doing these speed runs or do they just see nice cars going fast and leave you alone?

[Trond]

I got brake judder after my last trip in the mountains with heavy braking on some steep downhill sessions. I am sure it comes from brake deposits on he discs after heating up the pads too much and maybe not careful cooling afterwards.

Now 1000 kms later and quite some heavy breaking from high speeds the judder has more or less disappeared.

I beleive my breaking style has been the problem where I keep the foot on the pedal for 'easy' breaking and then heating up the discs. Hard and short breaking I hope will solve the brake judder issues I have had.

[hesperus]

Originally Posted by The Wind Breezes

Probably won't work but if you try it report back.

Also curious, do you have any problems with the authorities doing these speed runs or do they just see nice cars going fast and leave you alone?

Well, i live in a banana republic-- ok, that's starting to change little by little, but it is still a FAR cry from what it's like in Europe or the US. I lived in Boston for many years, so have seen both sides.

You can basically regularly get away with things here that would instantly land you in jail in the 'States. Take your pick of the typical scenario: a) you drive a Ferrari or Porsche and the cops will usually not bother you; b) they do stop you and you know someone in a high place and they let you off with a smile and a salute; c) you just bribe them.

But as they say, God is fair.

People can drive like idiots and get away with it, but we have almost literally the worst driving conditions in the world. Waze (the driving app) recently pronounced us to have the worst traffic. So it's becoming increasingly more difficult to actually enjoy one's car.

In that respect, the 1M is ideal. Fast enough to be able to enjoy at not homicidal speeds on when the roads are relatively open (holidays, early mornings,) and with enough ground clearance to navigate the terrible road surfaces.

We do have a pair of racetracks that are decent enough, so that's really the ideal place to enjoy the cars.

[The Wind Breezes]

I understand. I've never been to your country but I spent a lot of time in China 10+ years ago and it was a similar situation there.

That's funny you mention crappy roads, we have the same problem where I live and sometimes I want nothing more than rally suspension, haha.

[HP Autosport]

Congrats on the 1M ownership. I miss mine.

Take a couple of thousands of material off the rotor surface and sand down the pads a bit so you can do a fresh bed-in.