Is this rotor actually mill balanced?

[Bmsluite]

Usually when I get rotors you can see on the outside edge a milling mark where they have balanced the rotor. I do not see any milling done on this rotor yet Raybestos claims these are mill balanced. All I see is this little nub which looks cast. Is there another way to mill balance a rotor that I am unaware of?

I got these Raybestos rotors from Rockauto. Raybestos also supplies these rotors for AC Delco for their professional line. Usually I trust Raybestos 100% but I have just never seen a rotor without the mill marks. Especially not a $75 rotor (normal cheapos are about $40).

Any mechanic or auto industry guru who has an answer to this?

 

[Trav]

They may not have needed to be balanced.

What Is Mill Balancing?​

A mill balancing machine is a single piece of equipment that spins the brake rotor at high speeds and measures for imbalance as it is spinning. If an imbalance is present, the machine uses a milling blade to notch the “heavy” side of the rotor on the edge. The notching is placed between the friction contact areas to avoid interference with the brake pads during operation. The machine mills out just enough material that the weight of the milled material equals the amount of imbalance. The machine then spins the brake rotor at high speeds again to verify the balance of the brake rotor.


It is worth noting that some brake rotors may not have a notch on the edge. However, the brake rotors were still checked for balance and checked out okay before being passed through to the next phase of manufacturing.

Mill Balancing: Why Is There a Notch in My Brake Rotor? | PowerStop

Is there a machined notch in your brake rotor? This is for mill balancing, which can reduce vibration and improve the life of your brake rotor.

www.powerstop.com

 

[CharBaby]

I’ve had rotors that advertised to be mill balanced where one was and the other wasn’t. The non balanced rotor probably didn’t need to be as it must have been machined in spec(coincidentally) according to the manufacture. I’ve even purchased tires where one tire required very little weight and the other three much needed more.

 

[Bmsluite]

I’ve had rotors that advertised to be mill balanced where one was and the other wasn’t. The non balanced rotor probably didn’t need to be as it must have been machined in spec(coincidentally) according to the manufacture. I’ve even purchased tires where one tire required very little weight and the other three much needed more.

Thank you. This is what I thought may have happened but was not sure

 

[Bmsluite]

I’ve had rotors that advertised to be mill balanced where one was and the other wasn’t. The non balanced rotor probably didn’t need to be as it must have been machined in spec(coincidentally) according to the manufacture. I’ve even purchased tires where one tire required very little weight and the other three much needed more.

Gotcha. Thank you for your reply and the info

 

[Dave9]

Put it on. Test. Return if problematic.

 

[SixSpeed5]

I just purchased a set of four of these rotors, none of them having any mill balancing marks. They do not balance out well, one in particular is noticeably out of balance, on that rotor you can tell the machining is not centered with the casting (fins and inner hat out of round significantly). It was rubbing the backing plate which is what caused met to look closer at these rotors.

Not to mention they have surface rust forming after just being in a humid shop for a few days.

Called Raybestos, so far they are treating this like an interrogation where I am the bad guy for asking about their balancing methods.

Honestly these seem like a junk product. I’ll update if I make it anywhere with them.

 

[SixSpeed5]

Warrantied the two worst ones, new batch has no balancing marks, I will put them on the balancer and see whats up. I looked at several on the shelf at the local parts stores, none had balancing marks. I’m real sure they are falsely claiming to balance these rotors. One of them even had a poor casting (chunk missing) that is larger than a lot of MFG’s balancing material removal.

 

[The Critic]

Warrantied the two worst ones, new batch has no balancing marks, I will put them on the balancer and see whats up. I looked at several on the shelf at the local parts stores, none had balancing marks. I’m real sure they are falsely claiming to balance these rotors. One of them even had a poor casting (chunk missing) that is larger than a lot of MFG’s balancing material removal.

Very few of the aftermarket rotor mfgs have their own facilities overseas. They’re merely buying from a group of suppliers; there is minimal (if any) final QC after the rotors come onshore.

 

[vwmaniaman]

I bought two new rear drums for my 1990 Ford Ranger and the drums were so far out of balance I thought my new tires needed to be re-balanced. I put them on my bubble balancer and it was obviously way off. Both were that way. I put my old ones on the balancer since they were both still good and they balanced perfectly. I had them too long to send them back so I just ate the cost. Thanks Raybestos for destroying your reputation with me. Find another sucker.

 

[Dave9]

^ Take some material off?

 

[Bfrost99]

I make rotors for a living, very precise ones for Mercedes. Some get one balance cut, some two, and some no cut at all.

 

[nicholas]

Warrantied the two worst ones, new batch has no balancing marks, I will put them on the balancer and see whats up. I looked at several on the shelf at the local parts stores, none had balancing marks. I’m real sure they are falsely claiming to balance these rotors. One of them even had a poor casting (chunk missing) that is larger than a lot of MFG’s balancing material removal.

Sooooo
What's up with these.

Did you test them?

 

[meep]

Well, this answers a question I was asking about raybestos vs centric for my son. Centric it is!

 

[The Critic]

Well, this answers a question I was asking about raybestos vs centric for my son. Centric it is!

Same company now.

 

[meep]

Same company now.

Oooof. Who do you go with?

 

[researcher]

Oooof. Who do you go with?

For me I've had really good quality with Bosch quietcast rotors.. haven't had one yet that doesn't have almost perfect run-out measurements!

 

[SammyChevelleTypeS3]

I just purchased a set of four of these rotors, none of them having any mill balancing marks. They do not balance out well, one in particular is noticeably out of balance, on that rotor you can tell the machining is not centered with the casting (fins and inner hat out of round significantly). It was rubbing the backing plate which is what caused met to look closer at these rotors.

Not to mention they have surface rust forming after just being in a humid shop for a few days.

Called Raybestos, so far they are treating this like an interrogation where I am the bad guy for asking about their balancing methods.

Honestly these seem like a junk product. I’ll update if I make it anywhere with them.

The sad story to the attitude you got from Raybestos is likely something none of us want to hear or know about. The person giving you the bad attitude or strange response probaby has ZERO idea of what you are asking. I keep running into this issue everywhere since before and especially after covid. It seems everyone with experience who worked for these places has retired and all of these employers are stuck hiring all kind of folks with little and most times zero experience or knowledge about the jobs they are put into.
*Example* I went into the Honda Dealership I been using for auto parts and some maintenance for over 25 years. I walked into their parts department. Instead of the older / knowledgeable parts counter guys ..... there was a 20 something guy sitting there who (not kidding) struggled with English and after telling him what I wanted 2-3 times he looked at me puzzled and looked around for help until an older guy showed up. From what I could see the very frustrated older guy was trying to explain to this guy what we were attempting to do. Once the older fellow took my info , he had to take over. Best part is they did not even keep an under $50 part in stock. I had to make another 25 min drive back there days later to pick it up. The same young fellow was at the counter and tried to tell me "no part , your order not here!" after they texted me to pick it up. I had to ask for some help from another counter and they had my part.