[Anthonyd335]

Hi everyone,

I’m looking for recommendations for the best brake rotors to match with my hawk hps 5.0 street pads.

I’ve tried ordering Stoptech and EBC but they are all backordered for months.

I currently have Zimmerman rotors from fcp that warped within 2 weeks of use with moderately hard braking. (No track use or anything crazy like that)

I’ve also heard that the power stops can warp easy.

If anyone has any other brands to recommend I’d be glad to hear, or if anyone knows where I could potentially find Stoptech’s or EBC’s in stock that would also be great.

My car is a 2015 335i xdrive M-Sport with the sport brakes and 340mm front rotors.

Thanks!

[kickthecan]

Unless you go for a no name brand, you really will just settle with waiting for the backorder then since it seems that you've lost trust with zimmerman


But my Zimmerman with hawk 5.0 pads have been fine. 370mm fronts for me

[Ennoch]

I've not had any issue with the Zimmermans either (although admittedly 370mm two piece rather than 340mm), and I've had them pretty purple from hard use. However, it could be the pads are depositing material on the discs rather than actual warping, have you checked what the runout actually is? If you get pads hot enough and then stop with your foot on the brake then this can also cause issues with differing hardnesses of the rotor surface as well as pad transfer material. If there's little to no run out then I would be looking to scuff the surface up with 80 grit and then re-bed the pads in, or try some different pads before you change the rotors out.

[Anthonyd335]

Originally Posted by Ennoch

I've not had any issue with the Zimmermans either (although admittedly 370mm two piece rather than 340mm), and I've had them pretty purple from hard use. However, it could be the pads are depositing material on the discs rather than actual warping, have you checked what the runout actually is? If you get pads hot enough and then stop with your foot on the brake then this can also cause issues with differing hardnesses of the rotor surface as well as pad transfer material. If there's little to no run out then I would be looking to scuff the surface up with 80 grit and then re-bed the pads in, or try some different pads before you change the rotors out.

Haven’t tried to see if there is runout, I just needed to replace my front rotors desperately at the time so I bought a cheap kit off fcp.

I’m not sure how hard you push your brakes but I’ll admit I’m pretty hard on mine and I’m just looking for something that will withstand that abuse.

Maybe I’ll give the zimmermans another try. I see many people saying they are good but I just had one bad experience so I was unsure about them.

[Ennoch]

I'd try the runout first, if that's zero then scuff the discs back with 240 grit by hand to remove the shine and get them back to clean metal, scuff the pads, and try again. I take it the pads were new with the discs? Did you go through a bedding in process? I try to give the discs some gentle heat cycles with the pads before really going through an aggressive bed in procedure (if it's required). OEM spec pads tend to just need driven for a bit before they're at their best. If you just went out and caned it from the off that could have caused uneven pad deposits on the disc which could give the feel of warped rotors (going back to checking that with runout). Is there a potential you could have kept your foot hard on the brakes after coming to a stop with the brakes hot?

Well I wouldn't say I'm the hardest on brakes, but I've averaged less than 20mpg in the 335d for two hours across the Highlands, had the discs on my Impreza glowing at night and generally have trails of brake dust along the sills and lower half of the doors on most cars I've owned. However, I do bed discs and pads in properly, clean faces meticulously and when having a hard run do generally warm the car into it and cool it down after rather than going hard from the off and then just switching off at the other end with everything smoking. That can all make a difference over how well something works.

[johnung]

Originally Posted by Anthonyd335

Hi everyone,

I’m looking for recommendations for the best brake rotors to match with my hawk hps 5.0 street pads.

I’ve tried ordering Stoptech and EBC but they are all backordered for months.

I currently have Zimmerman rotors from fcp that warped within 2 weeks of use with moderately hard braking. (No track use or anything crazy like that)

I’ve also heard that the power stops can warp easy.

If anyone has any other brands to recommend I’d be glad to hear, or if anyone knows where I could potentially find Stoptech’s or EBC’s in stock that would also be great.

My car is a 2015 335i xdrive M-Sport with the sport brakes and 340mm front rotors.

Thanks!

M Sport Brakes on an F30 335i have Blue calipers and Fronts are 370x30 and Rears are 345x24. Sounds like you have standard grey brakes that are F340x30/R330x20.

Zimmermann are high quality German made rotors. They are unlikely to warp. Definitely try to clean them up as you were advised and rebed them.

TireRack has StopTech rear crossdrilled rotors in stock.

[Anthonyd335]

Originally Posted by Ennoch

I'd try the runout first, if that's zero then scuff the discs back with 240 grit by hand to remove the shine and get them back to clean metal, scuff the pads, and try again. I take it the pads were new with the discs? Did you go through a bedding in process? I try to give the discs some gentle heat cycles with the pads before really going through an aggressive bed in procedure (if it's required). OEM spec pads tend to just need driven for a bit before they're at their best. If you just went out and caned it from the off that could have caused uneven pad deposits on the disc which could give the feel of warped rotors (going back to checking that with runout). Is there a potential you could have kept your foot hard on the brakes after coming to a stop with the brakes hot?

Well I wouldn't say I'm the hardest on brakes, but I've averaged less than 20mpg in the 335d for two hours across the Highlands, had the discs on my Impreza glowing at night and generally have trails of brake dust along the sills and lower half of the doors on most cars I've owned. However, I do bed discs and pads in properly, clean faces meticulously and when having a hard run do generally warm the car into it and cool it down after rather than going hard from the off and then just switching off at the other end with everything smoking. That can all make a difference over how well something works.

I did attempt to bed them when they were new and since I have new pads I’m just gonna buy all new rotors but since everyone is saying Zimmerman is decent I’ll try them again and make sure I go through the correct bedding process and if I have issues I’ll try scuffing both surfaces. Thanks for the advice.

[Anthonyd335]

Originally Posted by johnung

M Sport Brakes on an F30 335i have Blue calipers and Fronts are 370x30 and Rears are 345x24. Sounds like you have standard grey brakes that are F340x30/R330x20.

Zimmermann are high quality German made rotors. They are unlikely to warp. Definitely try to clean them up as you were advised and rebed them.

TireRack has StopTech rear crossdrilled rotors in stock.

Yes I have the m-sport package with just the sport pckg grey calipers.

I’ll give Zimmerman another shot. Also I tried ordering the stoptech rotors from tire rack initially and I got a phone call after saying they were backordered, they show in stock online but they aren’t actually.

[xpro]

I ordered a full set 370mm of a company in Belfast Mtec Brakes.

They make their own in house rotors and they are seriously good and very very good value.
One gotcha is you need to specify if you want them power coated for rust or leave them plain. This is a must have!! Check them out

[Tommi_Mav]

Originally Posted by Anthonyd335

I did attempt to bed them when they were new and since I have new pads I’m just gonna buy all new rotors but since everyone is saying Zimmerman is decent I’ll try them again and make sure I go through the correct bedding process and if I have issues I’ll try scuffing both surfaces. Thanks for the advice.

Don't know which rotors you bought from Zimmerman, but better try the 2-piece rotors this time.

[Ennoch]

Originally Posted by Anthonyd335

I did attempt to bed them when they were new and since I have new pads I’m just gonna buy all new rotors but since everyone is saying Zimmerman is decent I’ll try them again and make sure I go through the correct bedding process and if I have issues I’ll try scuffing both surfaces. Thanks for the advice.

Fair enough, I get the logic of that. If you can, go two piece. They reduce unsprung mass and help pull heat out of the rotor surface as they have a greater thermal conductivity. How much that actually changes things on a stock car in practice is anyones guess though, and I've not seen anyone test brake temps on stock 1 an 2 piece rotors on these cars. I've certainly not had any issues with the 2 piece rotors.

You really should test the run out of the rotor currently installed though as if there's an issue with that it's most likely down to be dirt or corrosion on the hub assembly, but it is entirely possible that you could have sticking pistons which could be leading to the localised hotspots on the rotor surface I mentioned before. One other quick Q; can you feel any pulsing through the pedal or is it all coming from vibration through the wheel/seat?

[thejeremyman9]

Originally Posted by Ennoch

I've not had any issue with the Zimmermans either (although admittedly 370mm two piece rather than 340mm), and I've had them pretty purple from hard use. However, it could be the pads are depositing material on the discs rather than actual warping, have you checked what the runout actually is? If you get pads hot enough and then stop with your foot on the brake then this can also cause issues with differing hardnesses of the rotor surface as well as pad transfer material. If there's little to no run out then I would be looking to scuff the surface up with 80 grit and then re-bed the pads in, or try some different pads before you change the rotors out.

This is good advice. Stopping with your foot on the brake when the pads and rotors are very hot is the #1 way to get a pad deposit on the rotor, which people perceive as a "warped rotor". Just like you would take a cooldown lap at the track, after hard braking drive for a short period without using the brakes and if you must stop when the pads and rotors are still hot shift into P and keep your foot off the brakes.

[cfm56d7b]

Installed M Sport equivalent Zimmermann 2 piece rotors on all 4 wheels a few months ago. No problems.