[tranquility]

I can't find the thread discussing this but someone mentioned that one only needs to replace pads and that the dealers/etc are just telling you to waste money getting new rotors when it's not really needed. I wonder how true is this and if so does it depends on some factors? What is your opinion? TIA.

[overcoil]

depends

[///MPhatic]

Never arbitrarily replace the rotors or pads, check the minimum width on each (inside and outside).

And the calipers above won't work, they will stop at the top edge of the caliper that the pad never touches.

You'll need a set of real rotor measuring calipers.

And yes, it's worth your time and trouble to buy such a thing with brakes this expensive.

I also recommend buying from FCP Euro because they will literally replace them when you wear them out.

Except the pads, if you don't track your car I suggest Akebono's for the blue brakes, and CarboTech 1521's for the 2NH.

https://www.amazon.com/Anytime-Tools...s%2C105&sr=8-1

[chad86tsi]

If you have glazed your rotors from frequent granny-slow stops or break dragging, you might need new rotors if you want those pads to last or work well, glazed rotors doo a poor job of bedding in new pats. If you have a habit of hard breaking and then holding break pressure at the end while stopped, you can cause dissimilar hardness in the rotors metal grain structure, this will lead to pedal pulsing or rapid warpage while bedding in new pads. Turning the rotors won't eliminate these hard spots.

So yes, it depends. On domestic cars where rotors are cheap, it's great insurance to just get new rotors. I've been pretty lucky with just pad swaps though, but my driving style predicts this outcome. My wife is a granny stopper and break Dragger. Her Escalade developed a break squeal. A week of me driving it while on vacation cured the squeal.

[gameson]

If you need to replace brake pad and rotor, might be worth while to upgrade to BBK Big Brake Kit. Why replacing with the same parts?

[tranquility]

I'm not anywhere near a gearhead unfortunately, so I won't have much use for that tool. I'm just going to pay someone to change the parts for me. I don't track at all, so I assume just getting the OEM replacements is good enough?

Do most of you guys just get new pads?

I'm pretty darn good w my brakes, they lasted 6 figures in km, so I have a soft touch.

[BMWCCA1]

You should be able to get a pretty good idea by just looking at the rotors through your wheels. If they are rusty or scored, or have a large lip on the outside edge, pretty good idea to replace the rotors, too. I'm normally replacing rotors every second set of pads. Sometimes three! (Actually, I can't remember the last time I replaced rotors on any of my BMWs.) I would never use stock pads again unless you just like cleaning brake dust off your wheels all the time.

[///MPhatic]

Originally Posted by tranquility

I'm not anywhere near a gearhead unfortunately, so I won't have much use for that tool. I'm just going to pay someone to change the parts for me. I don't track at all, so I assume just getting the OEM replacements is good enough?

Do most of you guys just get new pads?

I'm pretty darn good w my brakes, they lasted 6 figures in km, so I have a soft touch.

BMW stamps right on the rotor that there is 1.6mm of wear, so your mechanic can check that easily.

If you have the blue brakes I highly recommend Akebono pads.
If you have the big 2NH brakes I highly recommend the CarboTech 1521's.

Both will extend the life of your rotors at least 2x and have a massively less dust.

[freakystyly]

Ceramic pads do real well with low/no dust but wont perform as well as OEM. It's not really noticeable in every day street driving. I'm really happy with my switch to Akebono pads and realize they do sacrifice a wee bit of braking ability. If you plan on tracking the car, you shouldn't be using street pads anyways.

As for rotors, as mentioned above, visual inspection for deep grooves, etc and measure with a rotor caliper at multiple places on the rotor to see the average material left.

[cooolone2]

What actually sucks is nobody will cut rotors to a nice flat surface any more. They're too lazy or use ridiculous "warranty" excuses. But cutting to within rotor thickness tolerances is certainly ok, just nobody does it any more. Bigger issue is people balking at the coat of good quality rotors that actual wear correctly, not cheap China garbage that is water thin, warp easier and just aren't good. But hey, they saved $300 on their brakes!

Two most important parts of the car, any car...

Wheel/Tires!
Brakes!

Don't skimp! Lol

[///MPhatic]

Originally Posted by cooolone2

What actually sucks is nobody will cut rotors to a nice flat surface any more. They're too lazy or use ridiculous "warranty" excuses. But cutting to within rotor thickness tolerances is certainly ok, just nobody does it any more.

Turning rotors is becoming a thing of the past for more than just one reason. FNC coatings, super minimal tolerances to save weight, and the "warp" lie that has been fed to the public for way too long.

[tdott]

Originally Posted by cooolone2

What actually sucks is nobody will cut rotors to a nice flat surface any more.

It's not worth it to cut most rotors, cross drilled ones even more so. It's just not worth the time/labor and damaging cutting blades trying to cut cross drilled rotors.

It takes too long/cost too much and it's more efficient to just buy a new one.

I'd rather by the 1pc rockauto rotors than try to turn a set if I was being cheap.
But the proper way to do it, is FCP some OE or Original BMW ones.

[RM7]

Originally Posted by tdott

It's not worth it to cut most rotors, cross drilled ones even more so. It's just not worth the time/labor and damaging cutting blades trying to cut cross drilled rotors.

It takes too long/cost too much and it's more efficient to just buy a new one.

I'd rather by the 1pc rockauto rotors than try to turn a set if I was being cheap.
But the proper way to do it, is FCP some OE or Original BMW ones.

Hopefully few people are buying cross-drilled rotors that crack, most high performance cars come with solid vented rotors on hats/carriers. The cross-drilled thing is usually a sign to me that they aren't really serious about performance...just looks.

[///MPhatic]

Originally Posted by RM7

Hopefully few people are buying cross-drilled rotors that crack, most high performance cars come with solid vented rotors on hats/carriers. The cross-drilled thing is usually a sign to me that they aren't really serious about performance...just looks.

Another misnomer.

Most high performance cars come with drilled rotors because they're beautiful, and the cracks don't hurt anything at all if they ever form.

Track rats are getting slotted, but most performance cars aren't coming with them.

CCB is all the rage, but they aren't cost effective for track cars either, they are again, for beauty.

[tdott]

Originally Posted by RM7

Hopefully few people are buying cross-drilled rotors that crack, most high performance cars come with solid vented rotors on hats/carriers. The cross-drilled thing is usually a sign to me that they aren't really serious about performance...just looks.

You must not have experience with BMW M cars.

[zx10guy]

Originally Posted by cooolone2

What actually sucks is nobody will cut rotors to a nice flat surface any more. They're too lazy or use ridiculous "warranty" excuses. But cutting to within rotor thickness tolerances is certainly ok, just nobody does it any more. Bigger issue is people balking at the coat of good quality rotors that actual wear correctly, not cheap China garbage that is water thin, warp easier and just aren't good. But hey, they saved $300 on their brakes!

Two most important parts of the car, any car...

Wheel/Tires!
Brakes!

Don't skimp! Lol

Turning/lathing rotors actually increase the rotor's propensity to warp, decreases heat capacity, and lowers the strength of the rotor. It's simple materials and physics. When you're turning the rotor, you're removing metal.

[zx10guy]

Originally Posted by ///MPhatic

Never arbitrarily replace the rotors or pads, check the minimum width on each (inside and outside).

And the calipers above won't work, they will stop at the top edge of the caliper that the pad never touches.

You'll need a set of real rotor measuring calipers.

And yes, it's worth your time and trouble to buy such a thing with brakes this expensive.

I also recommend buying from FCP Euro because they will literally replace them when you wear them out.

Except the pads, if you don't track your car I suggest Akebono's for the blue brakes, and CarboTech 1521's for the 2NH.

https://www.amazon.com/Anytime-Tools...s%2C105&sr=8-1

Or a micrometer.

[DocL]

A few months ago my brake wear warning came up on my car. The dealer said all I needed were new pads. They wanted $750 for new front pads. I got Akebono pads with the sensor included and did a DIY. It took me an hour taking my time and I saved $650.

The only time I replaced both rotors an pads was when I tracked Gen1 NSX a lot. I figure the next time I need new pads on my F80 I'm going to do rotors also. That will be at around 70k miles with my current driving and no track time on my car.

[///MPhatic]

Originally Posted by DocL

A few months ago my brake wear warning came up on my car. The dealer said all I needed were new pads. They wanted $750 for new front pads. I got Akebono pads with the sensor included and did a DIY. It took me an hour taking my time and I saved $650.

The only time I replaced both rotors an pads was when I tracked Gen1 NSX a lot. I figure the next time I need new pads on my F80 I'm going to do rotors also. That will be at around 70k miles with my current driving and no track time on my car.

Perfect post.

[DocL]

Originally Posted by ///MPhatic

Perfect post.

Thank you sir.

I go by the old rules before the internet. You look at the pads and edge of the rotors. For a street driven car if there's vibration you change the rotors. If only the pads are worn, just change those and the new one's will bed in fine. There's way too much over thinking nowadays.

[tranquility]

Thanks guys, I'm way over my head when talking about car mechanics. I just drive on the road, sometimes spiritedly, I treat my brakes w restraint and appropriate use, never slamming or pressing hard, I guess I try to be an optimal driver being efficient w them. My rears have lasted for ~200,000kms/125,000miles before finally coming up for replacing. Given this profile, I dunno if I need to get anything better than the OEM rotors/pads since I don't think I need greater stopping power (if they cost more than OEM), unless they are similarly-priced.

Here are the P/Ns and CAD prices to see if you guys have any more good advice:
BM34-21-6-797-861 $205
0066956P 12-16 w/300mm $119

Tbh, the difference between replacing the rotors as well is only an additional ~CAD240/USD185, so maybe I should just get them both done? Unless the shop says the rotors are still in top shape. I appreciate my indy, at least they are open to the idea that the rotors aren't a must to replace, vs the dealer who says that they must replace them.

[///MPhatic]

Originally Posted by tranquility

Thanks guys, I'm way over my head when talking about car mechanics. I just drive on the road, sometimes spiritedly, I treat my brakes w restraint and appropriate use, never slamming or pressing hard, I guess I try to be an optimal driver being efficient w them. My rears have lasted for ~200,000kms/125,000miles before finally coming up for replacing. Given this profile, I dunno if I need to get anything better than the OEM rotors/pads since I don't think I need greater stopping power (if they cost more than OEM), unless they are similarly-priced.

Here are the P/Ns and CAD prices to see if you guys have any more good advice:
BM34-21-6-797-861 $205
0066956P 12-16 w/300mm $119

Tbh, the difference between replacing the rotors as well is only an additional ~CAD240/USD185, so maybe I should just get them both done? Unless the shop says the rotors are still in top shape. I appreciate my indy, at least they are open to the idea that the rotors aren't a must to replace, vs the dealer who says that they must replace them.

I think you're good with the OEM rotors, but the pads are a different story. The OEM pads are a street/track pad, eat rotors, and you'll get no better street performance from them than you would a less expensive true street pad, which will also double the life of your rotors, be whisper quiet, and have 80% less dust. It's a no-brainer.