2 piece rotors: are these hats toast? Experience with racing brake 2 piece rotors?

[bogle]

My NSX came with a Brembo / Dali BBK installed by the previous owner. The BBK has 2 piece rotors which rattle quite a bit over bumps. I figured I could just install some new Brembo hardware with anti-rattle springs and be done with it (e.g. https://www.zeckhausen.com/catalog/index.php?cPath=6445).

I took the wheels off a couple days ago to inspect, and it looks like the hardware has dug into the alum hats. Note that they look countersunk in the hats, and the nuts have spun such that the flat spot is up on the one closest to the camera. All the nuts on both hats look like this. I'm wondering if new hardware would still be loose, still rattle, and maybe even be dangerous.

Some questions, especially for those with experience with 2 piece rotors:

• Are these hats toast? Is hat wear like this normal?
• Anyone have experience with racing brake 2 piece rotors? They sell a direct replacement pair for this BBK https://racingbrake.com/standard-iron-brake/acura/2156. Do they rattle? Will they rattle over time? There are no springs on their hardware.
• Are there maintenance things I should be doing regularly on 2 piece rotors? How often?

<img style="max-width:100%" src="https://user-images.githubusercontent.com/69169/89734659-534c5780-da12-11ea-9910-835995862d06.jpg" />

 

[bogle]

Since posting this, racing brake got back to me and said this wear is not normal. I ended up buying the linked set of replacement rotors with new hats.

I think the old rotors were also racing brake. Did the Dali racing / brembo bbk use racing brake rotors?

At least the hardware appears to be—they use flanged hex bolts instead of Allen cap screws, and don’t have washers or springs.

I’m still curious how the hats got like this and how I can prevent similar wear on the new ones. These are too expensive to be replacing the entire rotor.

 

[jwmelvin]

Thanks for the interesting report. Are you using the anti-rattle fasteners in the new setup? Does RB have some other solution for their floating fasteners?

 

[bogle]

I'll be using their stock hardware installed by them. Allegedly the RacingBrake hardware is not prone to rattling, even without a spring / washers. They told me this via email:

Our (self-locking nut) does not require those so-called anti-rattle springs-which are useless-after assembly they become flat washers and serve no function. After assembled with our hardware the rotor will not rattle so no rattle spring is required.

I'm a little nervous the new rotors will rattle over time as I'm 90% sure the hardware on the current rotors are RacingBrake. The hardware on the old rotors looks exactly like that from https://racingbrake.com/assembling-stoptech-or-brembo-replacement-rings/:


<img width="398" alt="racing-brake-hardware" src="https://user-images.githubusercontent.com/69169/89240650-a1480200-d5b1-11ea-9825-74f98c931e55.png">


But they could have been messed up from the beginning. The last owner of the car told me he was disappointed when he installed the BBK cause the rotors rattled. The person installing them told him all floating rotors rattle. I did a little searching, and other people (with other cars, other BBKs) had reports of rattling too. I thought maybe it was just a thing no one talks about. Now I'm convinced they shouldn't rattle at all.


I'll take some pictures of the old rotors this weekend when I get them off the car. The hardware has a ton of play, kind of unsettling on such an essential part.


I got the new rotors today and they look a little different. The rings don't move at all on the hardware when tweaking by hand (yay!). Will post some pics of them soon

 

[bogle]

Allegedly the RacingBrake hardware is not prone to rattling, even without a spring / washers. They told me this via email:


> Our (self-locking nut) does not require those so-called anti-rattle springs-which are useless-after assembly they become flat washers and serve no function. After assembled with our hardware the rotor will not rattle so no rattle spring is required.


I'm a little nervous the new rotors will rattle over time as I'm 90% sure the hardware on the current rotors are RacingBrake. The hardware on the old rotors looks exactly like that from https://racingbrake.com/assembling-stoptech-or-brembo-replacement-rings/:

But they could have been messed up from the beginning. The last owner of the car told me he was disappointed when he installed the BBK cause the rotors rattled. The person installing them told him all floating rotors rattle. I did a little searching, and other people (with other cars, other BBKs) had reports of rattling too. I thought maybe it was just a thing no one talks about. Now I'm convinced they shouldn't rattle at all.


I'll take some pictures of the old rotors this weekend when I get them off the car. The hardware has a ton of play, kind of unsettling on such an essential part.


I got the new rotors today and they look a little different. The rings don't move at all on the hardware when tweaking by hand (yay!). Will post some pics of them soon

 

[bogle]

I got the new rotors on today and took some pics of the old ones. Check out how loose the hat is!

https://youtu.be/GVZDvIlICws

Oh man. The hardware is tight (like the bolt to the nut) but there is crazy play. There was uneven wear on the hats, the nuts dug harder into the hat toward the front of the car (when on top of the rotation). Makes sense, each time you’d grab the brakes the ring would slow and the hat would slam forward on the hardware :/

The ring dug pretty hard into the hat too:

Some other pics of the old. I’m not sure who made them. Could they be an old version of the racing brake? Are they brembos? I still think the hardware is racing brake.

And the new:

The new hats (0.273”) are much thinner (.19”) than the old (0.463”).

I was a little worried it would locate the disk differently in the calipers, or the .2” less offset would make my wheels hit the calipers. But it’s all good (17x8 ce28n +38)

I’m still curious how I keep these ones in good shape.....