Slotted Rotors for 370/345 Brakes

kern417 · 09-25-2018, 07:18 AM

Has anyone found rotors for the MSport/MPerformance brakes that are only slotted? No drilling or dimples. If not I'll just go with the regular blanks, but hoping someone's searching skills are better than mine because I can't find anything. Bonus points if they are 2 piece and don't cost $1k

alexng72 · 09-25-2018, 07:31 AM

I got mine from R1 concepts. Been using them for 4 set of rotors on my bimmers.

kern417 · 09-25-2018, 08:20 AM

Quote:

Originally Posted by alexng72

I got mine from R1 concepts. Been using them for 4 set of rotors on my bimmers.

Thanks man, I remembered seeing yours were slotted and dimpled but now I see they sell just slotted too. And the price isn't too crazy

Polo08816 · 09-25-2018, 08:22 AM

Quote:

Originally Posted by kern417

Has anyone found rotors for the MSport/MPerformance brakes that are only slotted? No drilling or dimples. If not I'll just go with the regular blanks, but hoping someone's searching skills are better than mine because I can't find anything. Bonus points if they are 2 piece and don't cost $1k

I believe Zimmerman (OEM) rotors from FCP Euro are two piece are like half the price as the original M Sport rotors.

FaRKle! · 09-25-2018, 10:47 AM

Stoptech AeroRotors have a slotted only option. Not worth it unless you track though.

If you do track, I'd look for a two-piece rotor over a one-piece.

kern417 · 09-25-2018, 01:49 PM

My priority is 2 piece like stock, then slotted if I can find them. I have a stock tune with light wheels/tires and don't want to add weight back on with cast rotors.

I will never track the car but my stock blanks already have some grooves with less than 6k on them due to things getting stuck in between the pad and rotor. I like having a rotor that is "self-servicing" and always has a clean surface. But I'm not willing to pay $500+ just for a set of rotors. At that price point i'll just OEM style blanks like Polo08816 recommended.

R32DBP · 09-27-2018, 08:13 AM

like said above, Stoptech has an option for slotted only option. I have that on my car and got them through Rockauto. Cheap and quick shipping.

kern417 · 09-27-2018, 08:52 AM

Thanks but those are 1-piece cast. Their 2-piece rotors are like $700 for just fronts.

R32DBP · 09-27-2018, 09:32 AM

Ahh okay gotcha. Sorry about that.

insanecoder · 09-27-2018, 10:20 AM

Quote:

Originally Posted by alexng72

I got mine from R1 concepts. Been using them for 4 set of rotors on my bimmers.

Dimpled & slotted front & rear for $450?
very nice

alexng72 · 09-27-2018, 11:33 PM

Quote:

Originally Posted by insanecoder

Quote:

Originally Posted by alexng72

I got mine from R1 concepts. Been using them for 4 set of rotors on my bimmers.

Dimpled & slotted front & rear for $450?
very nice

Yea man they look very nice too

yoon_209 · 01-03-2019, 10:52 AM

Quote:

Originally Posted by alexng72

I got mine from R1 concepts. Been using them for 4 set of rotors on my bimmers.

how are you liking your rotors so far?

i've heard mix reviews from really good to people complaining about squeaking.

Logicoeur · 01-03-2019, 08:55 PM

Aren't the oem 2 piece still entirely Cast? Where do you save the weight with them being 2piece?

FaRKle! · 01-04-2019, 12:05 AM

Quote:

Originally Posted by Logicoeur

Aren't the oem 2 piece still entirely Cast? Where do you save the weight with them being 2piece?

OE rotors have an Al hat which is connected to the iron rotor via large rivets. The hat isn't cast.

E30M CW · 01-04-2019, 12:43 AM

With a 2 piece rotor, the hat will attach to the disk with a few bolts around the outside of the hat. It's also possible for material between the bolt holes to be removed making them a little lighter.

Here are some of rotor weights I found showing the difference:

Front 370x30
BMW OE solid 2-piece rotor - 36.4 lbs
BMW OE slotted and dimpled 2-piece rotor - 26.2 lbs
Zimmerman slotted and dimpled 1-piece rotor - 29.2 lbs

Rear 345x24
BMW OE solid 2-piece rotor - 19.8 lbs
BMW OE slotted and dimpled 2-piece rotor - 18.8 lbs
Pilenga solid 2-piece rotor - 20.4 lbs
Pilenga slotted and dimpled 2-piece rotor - 19.2 lbs
Zimmerman solid 1-piece rotor - 21.0 lbs

Given the big weight difference between the BMW 370x30 solid 2-piece rotor and the BMW 2-piece slotted and dimpled rotor, it would seem to confirm that the hat of the slotted and dimpled rotor was aluminum, but that doesn't seem to be the case with the regular solid 2-piece rotor.

Honestly though, the difference between comparable 1-piece rotors and 2-piece rotors is only 3 lbs on the front brakes and a little over 1 lb on the rears. Unless you're flat out racing with the car it's unlikely you'd feel any difference in ride compliance, handling or braking distance.

kern417 · 01-04-2019, 08:03 AM

I just did lightweight wheels, summer tires, etc. and with stock tune the car feels much more responsive and peppy. I don't want to go backwards on that progress. I'm sure it won't make a huge difference, but if I'm upgrading then I'm going to do it right.

FaRKle! · 01-04-2019, 10:11 AM

Quote:

Originally Posted by E30M CW

With a 2 piece rotor, the hat will attach to the disk with a few bolts around the outside of the hat. It's also possible for material between the bolt holes to be removed making them a little lighter.

Here are some of rotor weights I found showing the difference:

Front 370x30
BMW OE solid 2-piece rotor - 36.4 lbs
BMW OE slotted and dimpled 2-piece rotor - 26.2 lbs
Zimmerman slotted and dimpled 1-piece rotor - 29.2 lbs

Rear 345x24
BMW OE solid 2-piece rotor - 19.8 lbs
BMW OE slotted and dimpled 2-piece rotor - 18.8 lbs
Pilenga solid 2-piece rotor - 20.4 lbs
Pilenga slotted and dimpled 2-piece rotor - 19.2 lbs
Zimmerman solid 1-piece rotor - 21.0 lbs

Given the big weight difference between the BMW 370x30 solid 2-piece rotor and the BMW 2-piece slotted and dimpled rotor, it would seem to confirm that the hat of the slotted and dimpled rotor was aluminum, but that doesn't seem to be the case with the regular solid 2-piece rotor.

Honestly though, the difference between comparable 1-piece rotors and 2-piece rotors is only 3 lbs on the front brakes and a little over 1 lb on the rears. Unless you're flat out racing with the car it's unlikely you'd feel any difference in ride compliance, handling or braking distance.

The blank 370mm rotor weight is erroneous. Whoever originally typed that up hit a "3" instead of a "2."

Having owned a set of blank and dimpled/slotted rotors here are the weights I measured on my scales:
-Hella/Pagid 370x30mm, two-piece, dimpled & slotted, 26lbs
-Hella/Pagid 345x24mm, two-piece, dimpled & slotted, 19.2lbs
-OE 370x30mm, two-piece, blank, 26lbs
-OE 345x24mm, two-piece, blank, 19.2lbs

And for comparison my Stoptech ARK front rotors now are 24lbs each.

Logicoeur · 01-04-2019, 11:09 AM

Quote:

Originally Posted by kern417

I just did lightweight wheels, summer tires, etc. and with stock tune the car feels much more responsive and peppy. I don't want to go backwards on that progress. I'm sure it won't make a huge difference, but if I'm upgrading then I'm going to do it right.

You're going have to pay almost a grand to get a real 2 piece on the front and save weight over OE. Ecs and Stop tech are our only options, with none at all for the rears.

There was a thread I found several weeks ago in my search for the same (going to go BBK). Someone tried to have real 2piece floating rotors manufactured for our cars and it would be too expensive to make a true floating 2 piece rotor. (thread here: https://f30.bimmerpost.com/forums/sh....php?t=1410210)

Ecs was actually the least expensive 2piece in our market, that actually saves weight. However, I believe stoptech makes them as well since ECS owns them now.

kern417 · 01-04-2019, 11:39 AM

Quote:

Originally Posted by Logicoeur

You're going have to pay almost a grand to get a real 2 piece on the front and save weight over OE. Ecs and Stop tech are our only options, with none at all for the rears.

There was a thread I found several weeks ago in my search for the same (going to go BBK). Someone tried to have real 2piece floating rotors manufactured for our cars and it would be too expensive to make a true floating 2 piece rotor. (thread here: https://f30.bimmerpost.com/forums/sh....php?t=1410210)

Ecs was actually the least expensive 2piece in our market, that actually saves weight. However, I believe stoptech makes them as well since ECS owns them now.

Why don't you consider the R1 concepts offerings 2 piece? I've seen several other 2-piece options, i just don't want the dimples on the rotors. Only slots.

Logicoeur · 01-04-2019, 12:21 PM

Quote:

Originally Posted by kern417

Quote:

Originally Posted by Logicoeur

You're going have to pay almost a grand to get a real 2 piece on the front and save weight over OE. Ecs and Stop tech are our only options, with none at all for the rears.

There was a thread I found several weeks ago in my search for the same (going to go BBK). Someone tried to have real 2piece floating rotors manufactured for our cars and it would be too expensive to make a true floating 2 piece rotor. (thread here: https://f30.bimmerpost.com/forums/showthread.php?t=1410210)

Ecs was actually the least expensive 2piece in our market, that actually saves weight. However, I believe stoptech makes them as well since ECS owns them now.

Why don't you consider the R1 concepts offerings 2 piece? I've seen several other 2-piece options, i just don't want the dimples on the rotors. Only slots.

Wasn't aware of the R1 offering

Vulpe · 01-04-2019, 01:07 PM

Their post in the vendor section does have this part in it, unless they came up with something recently.

Quote:

Originally Posted by r1concepts

**ALUMINUM HAT FRONT ROTORS NOT AVAILABLE AT THE MOMENT, ONLY FULL CAST ROTORS**

FaRKle! · 01-04-2019, 01:09 PM

Quote:

Originally Posted by Logicoeur

You're going have to pay almost a grand to get a real 2 piece on the front and save weight over OE. Ecs and Stop tech are our only options, with none at all for the rears.

There was a thread I found several weeks ago in my search for the same (going to go BBK). Someone tried to have real 2piece floating rotors manufactured for our cars and it would be too expensive to make a true floating 2 piece rotor. (thread here: https://f30.bimmerpost.com/forums/sh....php?t=1410210)

Ecs was actually the least expensive 2piece in our market, that actually saves weight. However, I believe stoptech makes them as well since ECS owns them now.

My StopTech ARKs (slotted version) were a hair over $700 shipped from TH Motorsports. They send out coupons regularly if you leave things in your cart and don't check out.

09-25-2018, 07:31 AM	#2
alexng72 Lieutenant 147 Rep 503 Posts Drives: 2015 F32 435i Black Msport Join Date: Oct 2015 Location: Mason, OH iTrader: (0)	I got mine from R1 concepts. Been using them for 4 set of rotors on my bimmers.
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09-25-2018, 10:47 AM	#5
FaRKle! Brigadier General 4015 Rep 3,538 Posts Drives: 328d Wagon, M2 Comp, i4 eD35 Join Date: Sep 2016 Location: Bay Area, CA iTrader: (4) Garage List 2023 BMW i4 eDrive 35 [0.00] 2017 BMW 328dx Wagon [0.00] 2021 BMW M2 Competi ... [0.00]	Stoptech AeroRotors have a slotted only option. Not worth it unless you track though. If you do track, I'd look for a two-piece rotor over a one-piece.
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09-27-2018, 08:13 AM	#7
R32DBP Lieutenant 181 Rep 396 Posts Drives: 2014 335i M Sport, 2004 .:R32T Join Date: Jul 2008 Location: New Jersey iTrader: (0) Garage List 2004 Volkswagen .:R32 [0.00] 2014 BMW 335i M Sport [0.00]	like said above, Stoptech has an option for slotted only option. I have that on my car and got them through Rockauto. Cheap and quick shipping. Attached Images
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09-27-2018, 09:32 AM	#9
R32DBP Lieutenant 181 Rep 396 Posts Drives: 2014 335i M Sport, 2004 .:R32T Join Date: Jul 2008 Location: New Jersey iTrader: (0) Garage List 2004 Volkswagen .:R32 [0.00] 2014 BMW 335i M Sport [0.00]	Ahh okay gotcha. Sorry about that.
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01-03-2019, 08:55 PM	#13
Logicoeur Lieutenant Colonel 990 Rep 1,934 Posts Drives: F30 335i xDrive Join Date: Feb 2018 Location: Boston iTrader: (0)	Aren't the oem 2 piece still entirely Cast? Where do you save the weight with them being 2piece? __________________ F30 335iX \| Remus Axleback \| Fabspeed Catted DP \| VRSF Comp IC \| 18X9 ET35 19lb MT1 \| 255/40/18 ECS \| Ohlins RT Millway Street \| Millway Control Arm Bushings \| Turner Endlinks \| TMH 75mm 14x1.5 Studs \| BMW MPerf LSD \| XDelete \| Pipercross Filter \| MHD Stg2 93
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01-04-2019, 12:43 AM	#15
E30M CW Private 3 Rep 58 Posts Drives: 2015 335Xi Join Date: Sep 2018 Location: Alberta iTrader: (0)	With a 2 piece rotor, the hat will attach to the disk with a few bolts around the outside of the hat. It's also possible for material between the bolt holes to be removed making them a little lighter. Here are some of rotor weights I found showing the difference: Front 370x30 BMW OE solid 2-piece rotor - 36.4 lbs BMW OE slotted and dimpled 2-piece rotor - 26.2 lbs Zimmerman slotted and dimpled 1-piece rotor - 29.2 lbs Rear 345x24 BMW OE solid 2-piece rotor - 19.8 lbs BMW OE slotted and dimpled 2-piece rotor - 18.8 lbs Pilenga solid 2-piece rotor - 20.4 lbs Pilenga slotted and dimpled 2-piece rotor - 19.2 lbs Zimmerman solid 1-piece rotor - 21.0 lbs Given the big weight difference between the BMW 370x30 solid 2-piece rotor and the BMW 2-piece slotted and dimpled rotor, it would seem to confirm that the hat of the slotted and dimpled rotor was aluminum, but that doesn't seem to be the case with the regular solid 2-piece rotor. Honestly though, the difference between comparable 1-piece rotors and 2-piece rotors is only 3 lbs on the front brakes and a little over 1 lb on the rears. Unless you're flat out racing with the car it's unlikely you'd feel any difference in ride compliance, handling or braking distance.
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