How much float in 930 floating rotors?

[Danish Dynamite]

I am working on the brakes on my 911 - see the thread:

Another ST-build - this time from Denmark

I got my floating 930 rotors on the car:













I noticed a sound when I turned the rotor on the right side. I thought it was the bearing, but it was the rotor. I is a little "loose" when I rock it grapping the top and bottom. The left one is rock solid on its ring.

The question is: Should there be any play on a floating rotor like the 930 or should it be rock solid on the ring?

Thanks,

Christian

[safe]

Yes, hence the term floating.
But it depends on the design of the hat to, my VCI hats have 1-2 mm of "float".
Don't expect the brakes to be quiet.

[jwasbury]

Hi Christian,

You've already visited my thread on the subject '79 930 - Brake refresh in progress

I recently installed a fresh set of rotors on my 930, and this time I flipped the ring so they do no float. They were much too noisy for street use in my opinion...I constantly felt like something was about to fall off the car

[Danish Dynamite]

Hey Jacob

Thanks for the reply.

What are the advantages of floating versus non floating? I just thought it was strange, that one roter was "loose" and the other one wasn't...

/Christian

Originally Posted by jwasbury

Hi Christian,

You've already visited my thread on the subject '79 930 - Brake refresh in progress

I recently installed a fresh set of rotors on my 930, and this time I flipped the ring so they do no float. They were much too noisy for street use in my opinion...I constantly felt like something was about to fall off the car

[Bill Verburg]

Originally Posted by Danish Dynamite

Hey Jacob

Thanks for the reply.

What are the advantages of floating versus non floating? I just thought it was strange, that one roter was "loose" and the other one wasn't...

/Christian

Floating allows the thermal stresses from repeated hard braking to dissipate w/o cracking something

Here'a pic of a bolt up 2 piece rotor hat(993) that didn't use a floating design, i use the same size rotors on my 993 but w/ a floating design, it works much better. Modern floaters use spring clips to keep the noise down

[danco_]

Resurrecting this thread from the grave.

I've been chasing down a "popping" noise while low-speed driving and have changed so many suspension parts thinking that I fixed it, only to find that it is in fact the floating factory 930 rotors with VCI hats.

Is there a 930 brake rotor/tophat product on the market that cuts down on rotor "popping" noise or am I stuck with a factory single piece 930 rotor?

Bill, thanks for your last post. It makes sense.

[H-viken]

Steve Weiner sells a non-floating hat that works really well

Johan

[danco_]

Originally Posted by H-viken

Steve Weiner sells a non-floating hat that works really well

Johan

Thank you. Spoke with Steve earlier and he does sell a proprietary 2-piece non-floating rotor for the 930 caliper. This is the "fix" to low-speed floating rotor noise that I'm experiencing.

Another suggestion I found from searching was flipping the retaining plate to effectively "lock" the floating rotors, thus, no more noise.

Wonder if the second option is viable? My rotors have plenty of life left and would hate to remove them.

[bkreigsr]

I've never seen a setup that doesn't use some kind of locking nut on the hat bolts?
Bill K