859-380-6846

Should I Have My Rotors Turned?

A Brief Overview Of Brake Rotors.

A simply diagram of automotive braking system

  • What are rotors? Rotors are the circular disc that sit behind the wheel of your vehicle. They are a key part of your vehicle’s braking system and are considered a regular maintenance item.
  • Why do brake rotors need to be replaced or repaired? Vehicle rotors take a lot of abuse while driving/braking the brake pads squeeze down onto the rotors creating the friction needed to stop your car.
  • What are brake rotors made of? Iron alloy is the most common material used in modern-day brake rotors.
  • What does turning rotors mean? Turning a brake rotor is the process of lathing down a thin layer of your brake rotors to bring them back to a symmetrical shape and remove unwanted rust/debris.

You can read more on what brake rotors are in our blog about brake rotors.

When To Replace Rotors vs Turning Rotors

New sets of rotors have what is called the “Nominal Thickness”.This is the proper amount of thickness deemed necessary for safe and prolonged braking while still keeping overall vehicle weight in mind by brake system engineers. Over time, brake rotors wear just like brake pads, causing them to become thinner, reducing their ability to absorb heat. The heat created by the friction takes a toll causing the metal in the rotors to warp. Warped rotors cause a vibration or pulsation while braking.

All rotors have what is called a “Discard Thickness”. This is the threshold where rotors are deemed to be too worn to be turned or lathed down. For example, the front brake rotors for a 2017 Toyota Camry come with a nominal thickness of 28mm and a discard thickness of 25mm. This leaves 3mm of wear before the rotors should be discarded. This doesn’t leave much room for error. Before considering whether to have your rotors turned you need to make sure there is enough thickness on the rotor to complete the lathing process and be able to still safely absorb heat, and stop your vehicle.

Can My Rotors Be Turned?

Most brake rotors require .15th to .20th of an inch or 3-5mm of metal to be shaved off in order to be properly turned. As stated before most modern-day rotors only have around 3-5mm of wear before they should be discarded. You should always consult with your vehicle’s manufacturer before having your brake rotors turned to determine if they’re able to be turned.

 

Conclusion

Except some heavy-duty trucks or European model vehicles, most modern-day vehicles do not have the required thickness to be lathed down and put safely back on the road. If you choose to have your brake rotors turned and taken below the “minimum thickness” they will likely warp within weeks to months and need replacing. Always consult with your vehicle’s manufacturer and ask for the measurements of your current rotors before deciding to have them turned. You can read more on how to measure your rotor’s thickness from this power stop blog. You can also read more of our blogs and others about brakes on Top 30 Brake Blogs