monkeypilot

All rotors are secured...I hope...ours float..they secure by lug bolts.

jprice@CPS

you saying that a floating rotor still floats when the wheel is secured? If so, how is that car gonna stop.. the rotor stops and the hub and wheel continue spinning.. lol

ryoung

and I agree.

<i>"Floating disc: The norm in racing, the floating or two-piece disc consists of a friction disc mechanically attached to the hat either through dogs or through drive pins. Properly designed this system allows the disc to dilate (grow radially) without distortion and to float axially, greatly reducing drag."</i>

My front Alcon and rear Stasis brakes both use fixed rotors, even though both are 2-piece.

<img src="http://pictureposter.audiworld.com/17157/alcon_rotor.jpg">

<img src="http://pictureposter.audiworld.com/17157/rotors_rear.jpg"><ul><li><a href="http://www.stoptech.com/whitepapers/glossary/d.htm">StopTech Glossary - D</a></li></ul>

AlanL

which means that the mounting aluminum "hat" that has the holes for the wheel lugs is a separate piece from the business portion of the rotor. In the case of the Stoptech product, the connection is a series of allen bolts that mount the hat to the rotor in an eliptical slot instead of a simple hole. The result is that the rotor can expand and contract while the hat that is held in place by the wheel lugs is fixed and never moves.

Our cars have a single piece rotor assembly where there are no such mechanisms.....

I have replaced the rotors on a Stoptech brake system on my old B5 S4 which means you remove the old rotor from the "hat" and then install the new rotor to the hat using precise torque (72 INCH/lbs) on those allen bolts. This requires a version of Locktite to keep the bolts in place while they allow for rotor expansion and contraction depending on temperature.

ryoung

Fixed calipers are inherently stiffer than floating calipers, which is an important reason that they're used race cars. Floating rotors are used primarily to avoid the problem of a coning disc during ultra high temperature racing conditions. I don't see any compatibility issues when using a floating rotor with a floating caliper, but imho, floating rotors are overkill on our cars.

However, I am an advocate of 2-piece rotors (w/ aluminum hat) for the unsprung weight savings, typically 10 lb/corner in the front and 5 lb/corner in the rear.

AlanL

assembly.

sayemthree

piece (not floating) - floating have a separate hub andthe sep disc and they are pinned together - so the disc can expand sep from the rotor - often hub is aluminium to save wieght.

Jet Jockey/A4 Pilot

<b>Free Floating rotors</b>. They do have special attachement points to allow the expension and contraction of the rotors.

Captain Sheetmetal

Two types: some rotors float laterally while in use--<b>that </b> is a floating rotor. Look at a motorcylcle rotor; it is fixed rotationally but it floats laterally and guess what? When the rotor stops, the bike stops.

Another type is a rotor mounted to the hat with slotted holes. There is no lateral movement, but the rotor is allowed to expand--radial movement--at a different rate than the hat. That is also a floating rotor.

Captain Sheetmetal

And there was some question as to when or not that would be a good idea with our floating calipers.