$42 Rotors on RockAuto?

[tlow98]

Originally Posted by pbonsalb

I agree that the further away from the center the more any added weight will matter but people make a big deal about saving weight on driveshafts, which are about 3 inches in diameter.

On a car that weighs 3,700lbs

But yeah, I'm with ya.

[roastbeef]

every bit counts. if you're not counting the pounds, you can count on being slow.

[brodiem]

Not to sound picky about a $40 rotor, but will the hats and any other surface not being covered by the pad turn to rust? I.e. I think the OEM rotors are coated to prevent surface rust? Are there any alternative DIY treatment methods to accomplish the same?

[WingZeroX5]

Okay the brakes came in today and my buddy helped out. They're good, test drove them slight shake in the beginning but that's because of the grease and dirt from the installation. It's inevitable to get some grease on the surface when working on them. But once they're burned off, braking is smooooooooth lol. I did notice a slight decrease in biting power, but I'm sure that's because of the new ceramic brake pads.

I only drove like 5 miles with couple of heavy braking attempts. Still have a lot of oil burning smell coming off of them.

The only issue i have now is rear parking brake adjustments, which is driving me crazy. I may have a loose cable (which the dealer pointed out a few months ago) on the pass rear side, which is making a dragging noise from the parking brake shoes touching the rotor. Could explain why it wasn't holding for the longest time with the old OEM rotors.

Adjusting parking brake is so annoying, I'm just going to have a shop do it.

[Richbot]

Do they not sell brakleen where you are

[tlow98]

Originally Posted by brodiem

Not to sound picky about a $40 rotor, but will the hats and any other surface not being covered by the pad turn to rust? I.e. I think the OEM rotors are coated to prevent surface rust? Are there any alternative DIY treatment methods to accomplish the same?

Yes, you can spray paint them with a high temp caliper type paint if you want.

I'm not sure if these have any rust preventive treatment on them.

Doesn't mention it, which is odd, even at this price.

[pbonsalb]

My BMW rotor face rust but driving cleans it off. The hats don’t rust and maybe they are zinc or other coated. I have had rotors on other BMW where that hat surface rusted, but they were aftermarket rotors.

I am more into performance than cosmetics. The rust that bothers me is the rust inside the rotor vanes that develops. My E90M3 rotors were so badly rusted inside that I have no doubt temperature dissipation through the vanes was affected. Some of the cross drilled holes were blocked by rust. It takes a few years of driving in seasonal conditions like rain and snow for the rust to develop. My fronts were at or below minimum thickness but my rears were still in spec. I threw them all out and bought new last year, at about 9 years and 90k miles.

[WingZeroX5]

Originally Posted by Richbot

Do they not sell brakleen where you are

Used up my last can of the chlorinated good stuff, did this late in the evening

[deansbimmer]

Oem rotor hats are aluminum- so no rust. They’re not coated or plated.

The $40 rotors are all iron, yes they’ll rust unless you paint the centers.

Either rotor will eventually rust internally as neither are coated or plated.

[rymerc]

I couldn't risk being a cracked-rotor victim at HPDE so I went for semi-fancy-pants zimmermans... BUT if someone wants me to T&E these at next hpde get em to me in the next 4 weeks and I'll see if they shitsplode at my leisurely street-tire pace.

I've seen centric premiums crack in as little as 2 sessions on C5s, makes me not really trusting of those.

[Richbot]

IIRC the Bendix docs state they're zinc coated, (looks like it might be a galvalume style coating) so that'll keep rust away for a while

That weight penalty is pretty substantial for an unsprung rotating mass, even if it is just the hub. Wheel control out back is at a premium already with the shock and spring way inboard and all those bushings everywhere. I'm out, mostly for my religious objection to adding weight to the car than for any practical reason

[EnVe46]

Interesting. I just replaced mine with very lightly used set of rotors and when I went to bed the new pads, it took A LOOOOT longer than 5 mins. You have to get them reeeeaaaaaally hot in my experience. I bet for most people on here these would be a good alternative, Im a stickler about certain parts so Id probably stick with overpriced OEM quality stuff, but can't see much wrong here for a common daily

[Richbot]

Have my hands on a rear now. The annulus between hat and friction surface on the rear Bendix rotor is less than 5mm. There is basically nowhere for air to get in there.

I don’t these are coated either. Looks like raw iron to me.

So yeah. Buyer beware from a performance standpoint. But it seems like it’s made to the same standards other cheap rotors are made; looks flat and relatively nicely machined for what it is. Not much or no weight taken out of the outside to balance it which is concerning

[Inflame]

The C5 rotors crack for different reasons than being a cheap centric rotor. (FYI, centric makes rotors for many manufacturers).

Thanks for taking pics and trying them out!

[piesauce]

I just ordered a set of these with brakepads. Hopefully mine come in looking identical lol.. Let's see what happens.

Thanks for the review WingZeroX5!

[SYT_Shadow]

I'd run these if I had an M3 to drive in winter... other than that, no

[dparm]

My perspective is this: it comes down to your particular use cases and what you prioritize, like many other things on the car.

For a panic stop on the road and general DD duties, I doubt these will perform any worse than the OEM rotors. I would definitely use some sort of paint or whatever to slow down the corrosion, but that's cheap and easy. And hell, for $42, even if they rust and look shitty in a year, just toss them and get a new set.

For a car like the M3, I would not run these if I regularly engaged in spirited driving (backroads, canyons, whatever) -- especially not on the track. This isn't a 2200 pound Miata that doesn't use its brakes a lot. A lot of serious track guys are already running BBKs or whatever so maybe the point is moot, but brakes are a safety item and in a demanding environment like the track I would NOT skimp.

That being said, I haven't seen these in person and side-by-side with an OEM rotor. The above photos don't scare me, but they're certainly a cheaper reproduction of the OEM part.

[WingZeroX5]

Originally Posted by piesauce

I just ordered a set of these with brakepads. Hopefully mine come in looking identical lol.. Let's see what happens.

Thanks for the review WingZeroX5!

I'm certain they're going to look identical, which was my initial concern. I was OK with it not being drilled, but upon opening the box, I was very surprised that they were. Like I mentioned earlier, someone else in a different forum bought the same rotors and they came drilled

Originally Posted by Inflame

The C5 rotors crack for different reasons than being a cheap centric rotor. (FYI, centric makes rotors for many manufacturers).

Thanks for taking pics and trying them out!

Originally Posted by Richbot

Have my hands on a rear now. The annulus between hat and friction surface on the rear Bendix rotor is less than 5mm. There is basically nowhere for air to get in there.

I don’t these are coated either. Looks like raw iron to me.

So yeah. Buyer beware from a performance standpoint. But it seems like it’s made to the same standards other cheap rotors are made; looks flat and relatively nicely machined for what it is. Not much or no weight taken out of the outside to balance it which is concerning

So I have like 150 miles on them so far, and I have to say they're very nice. No balance issues and the car drives AND brakes smooth. I was expecting shimmies as soon as I step on the brakes, but to my surprise, it was glass smooth!

I think they're coated. I accidentally sprayed the wheels when I was cleaning X5M's summer wheels and the rotor hat didn't rust.

[Megabrode]

Informative and amusing thread. And, BOOF, I'd like to know a little more about "Marissa."

WingZeroX5, your rotors look legit to me. I used Centric blanks on two previous M3's -- e36 and e46 -- with no undue fade or oddball wear compared to stock (DD and autocross only). No reason to believe rockauto knock-offs would be any different. They will be my choice next time around. Left over cash will fund a trip to Mexicali.

[dparm]

Originally Posted by Megabrode

Informative and amusing thread. And, BOOF, I'd like to know a little more about "Marissa."

WingZeroX5, your rotors look legit to me. I used Centric blanks on two previous M3's -- e36 and e46 -- with no undue fade or oddball wear compared to stock (DD and autocross only). No reason to believe rockauto knock-offs would be any different. They will be my choice next time around. Left over cash will fund a trip to Mexicali.

Centric is the company that owns StopTech. They make a lot of caliper rebuild kits and other brake components. I would put them a notch above the off-brand generic parts and on-par with OEM.

[TVMA Doc]

Originally Posted by JsL

Just for fun, added to cart. Shipping is $46, so brings my total to $205.14 shipped for 4 rotors. Didn't check out.

Devil is in the details.

[dreamspeed]

Originally Posted by pbonsalb

What serious track people think cross drilled rotors are the way to go?

The hard parking kind?