KOESTER AUTOMOTIVE
15315 DICKENS ST
SHERMAN OAKS, CA 91403
Tel: (818)986-7376
Cell: (818) 383-3788
Fax: (818)986-9788

KOESTER AUTOMOTIVE
Count on us for fair, friendly service!

What is a good rotor surface finish?

Machined surface finishes are usually measured with "Surface Profilometers." But for any given Rotor surface you can use a Relative Machined Surface (RMS) measurement. For example:

          A # 125 finish = fingernail finish, your fingernail will drag on this finish.

          A # 63 finish = a smoother finish, your fingernail will not drag, however you would be able to detect lines in the finished surface.

With the introduction of Anti-Lock Braking Systems, brake rotor finish tolerances are more critical. Manufacturer's are now providing surface finish specifications. They will specify, for example, a brake rotor surface finish of 60 Ra or Less" where Ra equals "Roughness Average."

 

 

 

 

 

 

Certifications &
Affiliations
ASA Member  ASE Brakes 
Better Business Bureau Member
State Emissions Repair
State Safety Inspection