StopTech Friction ring Hardware spinning

[surlynkid]

I'd post this in the brake section, but this is probably much more of a BBK track thing. My hardware is rotating as much as 45 degrees. It is biting into the hats. It would be as though the ring is stopping but the hub and hat are still going?? Both 380mm fronts are doing this. Has anyone seen this? This is my 3rd set of rings. I noticed when I used the race hardware on my 2nd set. That is the Trophy hardware with flat washer instead of Belleville washer. With my 3rd set I went back to Belleville washers. Functionally, the brakes work fine, but I know this should not happen.

[///Mobbin]

I'm still on my first set of rings but curious to hear the answer. I'm also curious, is the torque spec any different between the Trophy and non-Trophy kits?

[msan]

Mine are flush against the hat lip. Can't see how they would rotate...I don't have the trophy kit, just normal st60/40

[///Mobbin]

Looking at pictures of other Stoptech rotor hats, those flat sided nuts look like they sit flush against the ledge beneath them. Yours almost look like they have a gap under them, perhaps the wrong size nut??

[surlynkid]

Torque spec is the same. It is about 70 in-lb.

If I hammer them back straight, they are essentially flush. Hat is soft aluminum. Hardware is steel. Put enough torque on it on track and it just bites in I think.

I have the regular brakes - not Trophy. They share frictions rings and hats though. Same hardware except the washers that sit on the side with the socket head cap screw. I tried the Trophy washers and saw no benefit.

It seriously looks like caliper stops ring but hat tries to keep going with tires. Very hard brake zones at cota??

[///Mobbin]

LINK to Stoptech Drive Pin Installation Guide

Maybe something in here that would help. Loctite?

[surlynkid]

Nothing there I don't know or didn't do. They give a little green tube of loc tite for the hardware. After torquing, you place a drop or two in the center of the nut in my pictures. It wicks down the threads. The bolts are not backing out of the nuts. I've installed the original kit and front Friction rings two times after that. I'll buy new hats with my 4th set of rings just because of this, but normally that should not be necessary with the condition of my hats (aside from the gouges at the nuts).

[///Mobbin]

Originally Posted by surlynkid

Nothing there I don't know or didn't do. They give a little green tube of loc tite for the hardware. After torquing, you place a drop or two in the center of the nut in my pictures. It wicks down the threads. The bolts are not backing out of the nuts. I've installed the original kit and front Friction rings two times after that. I'll buy new hats with my 4th set of rings just because of this, but normally that should not be necessary with the condition of my hats (aside from the gouges at the nuts).

Nice that they give you the loctite. I'm out of ideas here, maybe someone else will chime in, surely this has happened before.

[msan]

Just looking at the pics and mentally rotating the nuts back to the right position, leads me to think there's too much of a gap between the nut and the hat lip...maybe it's the pic but mine have almost zero gap with the hat lip. Like maybe only one piece of paper width of gap

[surlynkid]

Erik Steinkamp at StopTech is investigating. I think it all ties back to the hardware kit designed to prevent knockback. I saw no difference on track using that hardware kit even on track sections known for knockback, so I went back to the street hardware kit.

[dbyrd]

Scott,
I have the Trophy kit, and when I replaced the rotors, they only had one hardware option that included the Belleville washers.

I took a quick photo of mine and they look more flush with the flat edge, but they're also starting to ever so slightly dig into the hat like yours.

[surlynkid]

If you want flat washers which is what they call race hardware which is supposed to help prevent knockback but allows them to make more noise, the part numbers for E92 M3 380x35mm are:

Driver - 31.846.1101.87
Passenger - 31.846.1102.87

With belleville washers and less noise, the part numbers are:

Driver - 31.846.1101.99
Passenger - 31.846.1102.99

Same price either way. They always have either in stock. The only difference in the two part numbers is which washers you get. The rest is the same. The rotors really rattle around with race hardware.

[bigjae1976]

If I had to make a guess...the bolt holes in the rotor hat are slightly elongated when new to allow thermal expansion. Over time, I would imagine that heat cycling may elongate the holes more than designed. That's the only way I would imagine those flanged nuts would have the room to turn.

I've never gotten past a second friction disc but I do know the rotor hats are consumable items. Not sure how many disc changes a rotor hat is good for.