Hi, Does anyone know what the thickness of the ceramic disc should be when new and what the minimum thickness is? I am looking at buying one and the seller have provided measurements but not weights. Thanks
The thickness of the rotor doesn't really change through use (the weight does). Each rotor should be stamped with a weight in grams as I recall. You have to remove the rotor and weight it. In the service manual they do show photos which help you evaluate the overall rotor condition, but it's not a perfect method. Give me a second and I'll dig up the photos of the rotors in the manual. The brake pads start at 10mm thickness. Depending on how many miles are on the car and/or if the pads have ever been changed before, you can get a pretty good indication of things by measuring the remaining pads. Ray
Here you go.. see attached PDF. Looks they do give a wear limit at 0.5mm / .020" max. I'm not sure if I ever wrote down my brake disc rotor thickness, but I'll look at my records and see if I can find anything. Ray
Okay, I did measure my rotors on my 458 during one service I did. The car had 9124 miles on it and (at that mileage) here are the rotor thicknesses I recorded: Front Right rotor thickness = 36.05 mm Front Left rotor thickness = 36.15 mm. I purchased the car used, so I can't really say what the new rotor thickness might have been. However, at 10,680 miles, Ferrari did a diagnostic on the car and according to the computer and number of brake pedal presses, the percentage wear on the front rotors came back that it should have been approx. 9 percent. Perhaps that information helps you somewhat. Ray
Thank you very much Ray for digging all of that out. It confirms the pads are new but that the rotors likely need to be weighted to get a feel for how used they are as the car I am looking at has done 39,600 miles and the rotor thickness is pretty close to yours as one is 36.01 and the other 35.93.
You're most welcome. Check the PDF file also, as it shows some images of the rotor surface(s) and what to look for. You should be able to have any Ferrari dealer pull the information regarding # of brake pedal pushes, which will allow them to extrapolate brake rotor percentage wear estimates for ya also. Ray
I have a 488GTB and believe they are the same discs as a 458. The front discs are 38.25 mm thick when new and should be replaced at 36.3 mm.
Rough rotors = finished. Why delaminates with high heat. You can smash rotors really quick if you let them get too hot. Smooth as glass rotors = good to go. That’s pretty much how I’d check them. Sent from my iPhone using FerrariChat
On a Ferrari 458 with 7000 miles what would you expect the ceramic rotor wear percentage to be? Would 18% wear indicate the car was tracked or driven hard?
18 percent sounds quite low and not something I would be concerned about. My 488 had 15K miles on it when I purchased it and the disc wear on the inspection sheet showed 30 percent.
These ceramic units are 100,000 mile rotors under normal, street driving conditions Nearly 20% wear after 7000 miles seems high to me
