Floating rotors?

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What does this mean? I am at the shop getting tires installed, I mentioned that my rotors shake when stopping from highway speeds. The owner checked run out and said it wasn't all that bad and he was surprised that I felt anything at all. He then mentioned that it has floating rotors common to Honda, Acura, Mercedes etc. and that the should be torqued by hand to the proper spec. What does this mean exactly?
 
Race cars and motorcycles have floating rotors (rotor is a separate piece connected to a hat with 'buttons' that allow slight movement between the two) and solid-mount calipers. Your Accord does not. It has solid rotors and floating (sliding) calipers like most road cars do. I have no idea what that guy was talking about.
 
By itself, runout does not cause pulsation unless it is extreme. Excessive runout causes disc thickness variation, and excessive disc thickness variation is what you feel (pulsation).

The spec for your vehicle is 0.002", so if he measured more than that amount of runout, you'll eventually have issues.
 
Unless somebody put them on, your car does not have floating rotors, it has traditional rotors. Floating rotors are an option for the Euro market from BMW motorsport and some aftermarket companies, they are definitely not a stock item on an Accord.

The Brembo's on my SRT8 don't have floating rotors.
 
Floating rotors are kind of slang for mechanics. Some cars have the screw that holds the rotor on and they call them 'fixed'. So when you take off your wheel and loosen up the caliper and bracket and can pull the rotor off by hand its floating on the studs. If your lugs are tight 80 ft/lbs or so torqued..and you feel a pulsing vibration in the pedal then most likely your rotors are warped.
 
Originally Posted By: krismoriah72
Floating rotors are kind of slang for mechanics. Some cars have the screw that holds the rotor on and they call them 'fixed'. So when you take off your wheel and loosen up the caliper and bracket and can pull the rotor off by hand its floating on the studs. If your lugs are tight 80 ft/lbs or so torqued..and you feel a pulsing vibration in the pedal then most likely your rotors are warped.




That would be the opposite here though, since most Euro cars and the Honda in question use retaining screws on the rotors that run into the hub, and this would be the case with the OP's car
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You can certainly feel pulsing in the pedal even if the rotors are "straight", but there are pad deposits on the rotor or other metallurgical problems. I replaced all four rotors on my Ridgeline for this problem. A shop turned them and said they were straight, but noted a difference in appearance on the metal. Indeed, about half the rotor looked bright shiny (typical) and the other half had a darker color to it, not unlike a burned bronze. This is after they had been installed and re-bedded with the pads. Only replacing the rotors is going to cure something like that.
 
Originally Posted By: gregk24
What does this mean? I am at the shop getting tires installed, I mentioned that my rotors shake when stopping from highway speeds. The owner checked run out and said it wasn't all that bad and he was surprised that I felt anything at all. He then mentioned that it has floating rotors common to Honda, Acura, Mercedes etc. and that the should be torqued by hand to the proper spec. What does this mean exactly?


He incorrectly named the part. Back in the day it was common for rotors to have the bearing installed in them along with the wheel studs, those you had to very careful torquing the wheel you could flex the rotor.
The rotor used on your car are just hats, they fit over a hub which either contains the bearing or is a stub shaft that goes into a cartridge bearing as on the front of your Honda.
Full floating as someone posted are held by buttons to the part that goes on the wheel in the case of a MC or a hub.

Before checking run out you must clean the hub face, rust can form and throw the run out off. If he didn't do this first the whole exercise was meaningless.
If the run out is slightly off just rotating the rotor on the hub may correct it when installing new rotors if not shims are available.
You possibly have uneven pad deposits on the rotor, do a few hard controlled stops from 60 mph, give it a min to cool down before repeating.
To halp prevent this, after hard braking coming off the highway for example don't sit there at the stop sign very long with your foot on the brake, use the e brake instead once stopped just keep light pedal pressure to keep the brake lights on but not apply pressure to the pads.
 
Originally Posted By: Schmoe
If it's throbbing at your feet, your rotors are trashed. Need cleaning


There, fixed it for you.

A throbbing pedal only means actual rotor damage in a tiny, tiny fraction of cases. Usually its uneven deposits of evaporated bad binder material accumulated on the brake rotors. Scrubbing them with Scotch Brite pad soaked in Brakleen works as well as replacing rotors in most cases.
 
Thanks for your responses guys. One thing that may be worth mentioning, they only vibrate after heating up. Also no pulsation is felt through the pedal.
 
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