Brake rotor/pad replacement

[MichaelInChicago]

My '15 650 GC now has 48,000 miles on it and I think it is time for a brake rotor/pad replacement. When I brake at highways speeds, there is a slight vibration and the rotors are starting to look that they are past their time, even though the pads seem to be in good condition.

- Is it normal for the brake replacement to be done at this mileage?

- Should I use BMW parts or is there an upgrade I should be looking at? There are so many options out there and I do not know where to order from or what components to buy (performance, slotted, OEM...etc.)

Thanks again for your help.

[Opie55]

48k on original pads? That's pretty good. Rotors depends on how they have worn and how much of a lip they have. There is a minimum thickness. But I tend to replace them anyway because they tend to wear unevenly - they get grooves and ridges in them. People debate pads much more than rotors. Zimmerman rotors are popular, and will save you some money. People often say BMW pads make too much dust, but I have not found that to be true on my 6 or my X3. But there is a 535 in my family that might as well have flat black wheels. Not sure why the difference.

[thebmw]

I have OEM rotors for the 650 if you are interested. Let me know.

[thiscarlife]

Braking tend to vibrate because the rotors come in contact with water (like during washes) when they're still hot which causes uneven surface. I think if they still have good life, you can just have the rotor machine shaved flat again and just replace worn pads to save some money. Had this done on my other car

[MichaelInChicago]

It does say that my pads are all OK on my vehicle status window on the main screen.

Maybe a simple refinishing would do the trick.

[Opie55]

Originally Posted by MichaelInChicago

It does say that my pads are all OK on my vehicle status window on the main screen.

Maybe a simple refinishing would do the trick.

As I said above, don't trust the status screen. Just look at them. Takes 2 minutes. And take your finger when the brakes are cold and feel for the lip at the very outer edge of the disc. If it has much of one, they are probably to thin to have them turned down smooth. But it depends on how you brake how much of lip has worn therein 49k miles. .

[jjasonSU]

I've got 40k miles and have the high speed shudder in front as well.

[Flying Ace]

As others have said there are many things to consider:

1. the shudder can be from pad's material deposit on the rotor. A simple resurfacing of the rotor should resolve the issue.

2. The bigger issue is that you haven't had a rotor or pad replacement at 48k. It's about time. But the only way to check this is to get a rotor measured for minimum thickness. The computer screen is an estimate of pad wear (not rotor wear) and it's only an estimate on one corner, not both.

I'm going to bet when you measure the rotor you're about 1mm away from a rotor change. In this case, it's not worth spending money on resurfacing, you might as well replace the rotor and pads (and sensor).

[thebmw]

No one resurfaces rotors anymore. Not worth the cost and may be dangerous/detrimental as there is less material. I'm a bit surprised that anyone, especially on the BMW forums, would recommend that.

Do the right thing and replace the darn rotors. Brakes are the most important part of the car...why would anyone cut corners?! It could cost you big time!

[MichaelInChicago]

As I said in my message, it does say my pads are ok. Also, when I run my finger along the disc up to the edge, it is all flush and there is no lip, so I am not sure if they need replacing yet.

The pads have been changed once but the rotors are original. I will have them measured when I bring my car in to have my Michelin Pilot Sport 4S tires put on this week.

[Flying Ace]

yep, the only true way to know about rotor wear is to measure it with the a tool.


Also, now that you've mentioned that you've had a pad replacement done, that explains the computer message. As I said before the wear indicator that feeds that message is only for an estimate on pad life, not rotor life. And it's only one corner of the car, not all 4.

[MichaelInChicago]

I know this is rough estimate, but I just measured the disc thickness at all four wheel and using a tape measure, I calculated them to be 23 mm rear and 34 mm front.

Comparing it to new rotor thicknesses on various carparts sites, they seem to be about right.

Any thoughts?

[jjasonSU]

Originally Posted by MichaelInChicago

I know this is rough estimate, but I just measured the disc thickness at all four wheel and using a tape measure, I calculated them to be 23 mm rear and 34 mm front.

Comparing it to new rotor thicknesses on various carparts sites, they seem to be about right.

Any thoughts?

You won't really notice the disc thickness variation with a tape measure.

[Flying Ace]

nope, you need a precision caliper tool.

[MichaelInChicago]

I am going to buy one tomorrow.

Would any of you know the minimum thickness for the front and rear rotors of a '15 650xi Gran Coupe (M Sport)?

Thanks

[MichaelInChicago]

Just installed my new Michelin Pilot Sport 4S tires and while at the garage they told me the front/rear rotors had 60%/40% remaining and they were still in good shape and to look at them again in late fall.

Thanks for all of your help.

[jjasonSU]

MichaelInChicago What did they say about the vibration

[MichaelInChicago]

They said it probably had to do with the two front tires, which has two bubbles each.

They asked me what type of vibration it was, and when I explained it felt like it was coming from the underneath of the car (not the pedal or steering wheel), they said that defective tires were the most probable culprit. Since changing the tires, the small vibration is almost all gone.

Whatever works.

And the tires are superb. Anyone who still has RFT's on should change them asap.It makes a world of difference.