[Kidu]

Hi all,

Anyone able to tell me if I can use aftermarket pads on existing OEM rotors? My front rotors and pads were replaced quite recently. My rear pads are below the percentage needed for HPDE and need replaced. Can I just put on EBC Yellow stuff pads on the existing OEM rotors? Is there anything else that would be better? Why is it that the BMW dealer said they (pads and rotors) had to be replaced together?
Thank you for enlightening me!

[khj24]

Unless they're past min thickness, you're totally fine putting aftermarket pads on OEM rotors. The dealer wants your $$$$

[Kidu]

Yeah thats what I thought too. on all my non-German cars, I was able to do that. I got the front ones replaced under warranty, so I didnt ask more. Now that the rear ones are going to be on my dime, I wanted to find out. Thanks. On the OEM rotors, what pads would be best for aggressive street/track use?

[khj24]

Originally Posted by Kidu

Yeah thats what I thought too. on all my non-German cars, I was able to do that. I got the front ones replaced under warranty, so I didnt ask more. Now that the rear ones are going to be on my dime, I wanted to find out. Thanks. On the OEM rotors, what pads would be best for aggressive street/track use?

Not too sure, I think most go with Pagid/Akebono/yellow stuff. I went with powerstop z23 ceramics because they were cheap and have low dust, I love them on the street, but I doubt they'd be good for the track.

[jondagger]

What is your cars mileage? I did both pads and rotors at 65k just incase...

My STI had worn rotors by 80k miles... replacing only your pads at 60k miles to later get wavy rotors at 80k miles is a waste of pad.

Also, check out stoptech street pads (produce like no dust and pretty good stopping power too). I slapped them on OEM rotors. Short brake play in the beginning, was odd, but it opened up.

[DrivingPassion]

Originally Posted by Kidu

[...]Why is it that the BMW dealer said they (pads and rotors) had to be replaced together?
[...]

Your rotors are probably under the threshold in terms of thickness. You can open it and measure the thickness and see if the dealer is telling the truth.

If it needs to be replaced, then replace it. I do want to let you know that replacing rotors is, theoretically, a simple procedure. But, to be realistic, bolts can get stripped, screws can get stuck. When these happen, it will take a few tries to get them out of the way before you can replace the rotors. You will need to manage your frustrations. I'm speaking from experience.

Pads are a lot easier to replace.

[khj24]

Originally Posted by DrivingPassion

Your rotors are probably under the threshold in terms of thickness. You can open it and measure the thickness and see if the dealer is telling the truth.

If it needs to be replaced, then replace it. I do want to let you know that replacing rotors is, theoretically, a simple procedure. But, to be realistic, bolts can get stripped, screws can get stuck. When these happen, it will take a few tries to get them out of the way before you can replace the rotors. You will need to manage your frustrations. I'm speaking from experience.

Pads are a lot easier to replace.

I concur, the caliper bolts are no problem, clearance is a bit of an issue however, but the damn rotor set screw can be an absolute pain. One was completely seized and took multiple trips to Home depot for drill bits to drill through it. I ended up removing the rear ones as a precaution and put new ones on with anti-seize. It only takes one to ruin your day.

[aerobod]

With the rotor screws, there are a few things that can be done to ensure successful removal without drilling to use an extractor:

- spray the existing screw with a penetrating / dismantling lubricant before attempting removal
- ensure that you use a metric allen key that is properly hardened and preferably with an impact wrench (any imperial key that is "close" in size will guarantee stripping)
- apply anti-seize to the new screw for easy removal on subsequent replacement.

I've replaced plenty of BMW rotors in the past and never stripped the screw head.

[khj24]

Originally Posted by aerobod

With the rotor screws, there are a few things that can be done to ensure successful removal without drilling to use an extractor:

- spray the existing screw with a penetrating / dismantling lubricant before attempting removal
- ensure that you use a metric allen key that is properly hardened and preferably with an impact wrench (any imperial key that is "close" in size will guarantee stripping)
- apply anti-seize to the new screw for easy removal on subsequent replacement.

I've replaced plenty of BMW rotors in the past and never stripped the screw head.

Yea this is definitely important, just want to note that somebody else stripped it as I bought it used and I found out the hard way.

[DrivingPassion]

I bought my M235xi as a CPO car, which came from MN. Looks like they salt their roads extensively and the rotor retention screws are all rusted and "infused" into the hub. They are impossible to remove: soaked it with PB Blaster; hex wrench stripped the screw off completely; I tried using sledge-hammer + spring-loaded left-hand extractor; I tried using the drill + extractor method, etc. Nothing works.

The only thing that worked is drilling it out. Even after the rotor was off the hub, the remnants of the damn screw was still impossible to get rid off in the hole on the hub. I had to use a tap wrench to cut it through.

That was how much effort it took because of that one screw. And, both front rotor screws are like that. I can imagine the rear wheels are similar.

I'm now going to replace the entire hub and bearing because I do not trust the integrity of the existing hub+bearing. Not sure how much the salt has affected the components.

[ggggbmw]

Originally Posted by aerobod

- apply anti-seize to the new screw for easy removal on subsequent replacement.

After reading so much about stuck rotor screws, I decided to do some preventive maintenance during my last track pad swap. I pulled all the screws, and applied anti-seize to all of them. Luckily they all came out easily, and it only took about 5 minutes on top of the other maintenance I was doing. Well worth it to do it before you need it.

As for whether your rotors need replacement, measure them. A cheap $20 digital caliper will work fine if you're careful to make sure you are on the wear surface, and not getting hung on any lip. Or buy a real rotor caliper. Cheap ones are in the $50-$60 dollar range. Yes another tool you may not use often, but it's nice to know for sure. It's kind of a pain to measure the rears, but the backing plate is surprisingly flexible. If you just push it away from the rotor it's not hard to get in and measure, and then just let it flex back to normal position.

[Maynard]

Originally Posted by Kidu

..... On the OEM rotors, what pads would be best for aggressive street/track use?

Brake Pad thread has lots of discussion of this (https://www.2addicts.com/forums/show....php?t=1355833). I'm loving my Ferodo DS2500's - Great on track, and on street they have minimal noise, surprisingly little dust, and good modulation. You'll regret trying to use a sport-street pad on track if it has much heavy braking (probably OK for autocross, but not real track). And Zeckhausen Racing is my go-to for detailed brake advice - may be worth a phone call for true expert and individualized advice.

[dradernh]

Originally Posted by Kidu

...what pads would be best for aggressive street/track use?

Originally Posted by Maynard

You'll regret trying to use a sport-street pad on track if it has much heavy braking (probably OK for autocross, but not real track).

^ This.

[keylime503]

Originally Posted by dradernh

^ This.

Obviously dedicated track pads are best for track work but if you had to choose between OEM pads and something like EBC yellow stuff for occasional track use which would you prefer?

[dradernh]

Originally Posted by keylime503

Obviously dedicated track pads are best for track work but if you had to choose between OEM pads and something like EBC yellow stuff for occasional track use which would you prefer?

I'm not familiar with EBC's line of pads, so I can't comment on them. I've only used my OEM pads on the street and have never asked much of them, but I know some other members here have used them on the track. Perhaps they can weigh-in with their experiences.

The basic issue with pads isn't the frequency of their use in high-demand situations; instead, it's how hot your braking system's components get during that use. Your brake pads act as a heat sink, and the greater their capacity to hold heat the less likely you are to boil your brake fluid.

Generally, the pads should also be matched to the grip level of the tires you're running - grippier tires call for pads that grip well at elevated temperatures. My take is that a novice or lower intermediate driver running OEM tires on the track may find that the OEM pad or a street/track pad are effective matches. If the driver is hard on his or her brakes, however, that probably won't be the case.

Below are photos of the brake rotor temperature paint I put on my rotors and the brake caliper temperature strips I put on my calipers. The caliper strip data is self-explanatory (it's in degrees Fahrenheit), and the rotor temp paint came with a scale to convert the color to a temperature range. Both items were put on before a trip to Mid-Ohio earlier this week, where I ran three sessions of 6-9 laps each and leaned on the car moderately hard.

These tools measure how hot those two brake system components got during an event. I use that data to tell me how close I am to boiling my brake fluid (not very) and if the car needs brake ducts (it does - the rotors are getting too hot). I'm in the process of figuring out if I can acquire effective brake ducts without paying a large sum for the creation of a custom, one-off set.

Genesis Brake Temp Paint on an M240i Rotor – Indicated Temp is ~1500 °F (this is a poor image - the paint color is a fairly bright yellow)


Genesis Temperature Indicating Strip on an M240i Caliper – Indicated Temp is >=350 °F & <390 °F

[keylime503]

I’ve used stock pads on the track for about 5 track days, they’ve held up just fine but I’m a novice track driver at best.

[overcoil]

For people fretting about the rotor set screw aren’t you supposed to use a MANUAL IMPACT DRIVER to remove the set screw ?

https://www.powertoolexpert.com/how-...utimate-guide/

[HP Autosport]

Originally Posted by jdag001

What is your cars mileage? I did both pads and rotors at 65k just incase...

My STI had worn rotors by 80k miles... replacing only your pads at 60k miles to later get wavy rotors at 80k miles is a waste of pad.

Also, check out stoptech street pads (produce like no dust and pretty good stopping power too). I slapped them on OEM rotors. Short brake play in the beginning, was odd, but it opened up.

Stoptech Sport is a great sport street pad!