New disc issue

[Cracker]

Bought a new pair of front discs online & both have a “groove” on the edge I didn’t think looked right.
Are they faulty? Cheers in advance.

 

[warmasice]

Bought a new pair of front discs online & both have a “groove” on the edge I didn’t think looked right.
Are they faulty? Cheers in advance.

Seen it many times before. Its just removal of excess material to ensure the disc is balanced. Fit away.

 

[Cracker]

Bought a new pair of front discs online & both have a “groove” on the edge I didn’t think looked right.
Are they faulty? Cheers in advance.

Seen it many times before. Its just removal of excess material to ensure the disc is balanced. Fit away.

Cheers for that Warmasice. Appreciate it

 

[VRSteve]

Seen it many times before. Its just removal of excess material to ensure the disc is balanced. Fit away.

No its not.
Its a wear indicator. When the material on the outside of the groove is worn the disk is at the end of its useful life.

 

[Nictrix]

Seen it many times before. Its just removal of excess material to ensure the disc is balanced. Fit away.

No its not.
Its a wear indicator. When the material on the outside of the groove is worn the disk is at the end of its useful life.

:lol:

 

[VRSteve]

Seen it many times before. Its just removal of excess material to ensure the disc is balanced. Fit away.

No its not.
Its a wear indicator. When the material on the outside of the groove is worn the disk is at the end of its useful life.

:lol:

Here you go

https://www.6speedonline.com/forums/996/298332-how-thin-can-brake-rotors-get-anyway.html

You can apologise on here, or by PM. I'm not fussed.

 

[Nictrix]

No its not.
Its a wear indicator. When the material on the outside of the groove is worn the disk is at the end of its useful life.

:lol:

Happy to be proved wrong.

I really cant see it being wear indicators for a few reasons.
The amount of material taken off the disc to reach that level would be huge.
When the disc wears it never wears at the edges so it would be difficult to see if the disc had reached these marks.
If it was wear marks surely they would have them the same sort of size equally spaced around the disc.

 

[VRSteve]

:lol:

Happy to be proved wrong.

I really cant see it being wear indicators for a few reasons.
The amount of material taken off the disc to reach that level would be huge.
When the disc wears it never wears at the edges so it would be difficult to see if the disc had reached these marks.
If it was wear marks surely they would have them the same sort of size equally spaced around the disc.

Oh so your laughing at me, although you have no idea yourself....you just think I'm wrong.

As I said in my post above, the link shows my reasoning, and corroborates my view.

 

[Nictrix]

Happy to be proved wrong.

I really cant see it being wear indicators for a few reasons.
The amount of material taken off the disc to reach that level would be huge.
When the disc wears it never wears at the edges so it would be difficult to see if the disc had reached these marks.
If it was wear marks surely they would have them the same sort of size equally spaced around the disc.

Oh so your laughing at me, although you have no idea yourself....you just think I'm wrong.

As I said in my post above, the link shows my reasoning, and corroborates my view.

Oh, I see you edited your post while I was answering.
Sorry, yes I did laugh at that and if you are correct I apologise.
I have never heard of this and still honestly dont think its right.
Who is the marks for? If its for the owner of the vehicle to visually check the disc thickness it would be very difficult to see on the car with wheels in the way and also as I said the fact that the edges of the disc dont wear.
If its for a garage, do they not measure the disc as there is normally a stamp on the disc saying minimum thickness?
As I said if you are correct I apologise.

 

[Nash3vans]

Either way they aren't faulty

 

[buzyg]

I think it's done to ballance the disks during manufacture. Not noticed it on mine though.

See Link. As You Tube seems to have stopped working when embedded into a forum post recently.

https://www.youtube.com/watch?v=vIJf29CFnbo

[youtube]vIJf29CFnbo[/youtube]

 

[Nictrix]

So whats correct?
A forum post from 4 years ago or a youtube video from 6 years ago.

 

[buzyg]

So whats correct?
A forum post from 4 years ago or a youtube video from 6 years ago.

Not sure I understand the point of your question. :?

However I believe the video is, as it clearly shows how the marks are made. Plus there are other similar video's of brakes being balanced using this method, all over the internet. :wink:

 

[Beedub]

This is a brake rotor balancing method....

heres the machine that does it...

http://www.directindustry.com/prod/cemb/product-7363-439494.html

 

[VRSteve]

In my garage I have a set of disks of HRH's mini.

The grove cut in the disk measures 8.4mm, the same as the minimum thickness stamped on the front of the disk.

I measured using a digital calliper, so I am MORE than happy that I'm correct in what I say.

 

[Ducklakeview]

:lol:

Happy to be proved wrong.

I really cant see it being wear indicators for a few reasons.
The amount of material taken off the disc to reach that level would be huge.
When the disc wears it never wears at the edges so it would be difficult to see if the disc had reached these marks.
If it was wear marks surely they would have them the same sort of size equally spaced around the disc.

It isn't a wear indicator at all. It IS for balancing the disc after its been machined.

The brake pads don't sweep that near to the edge and therefore even a well worn disc would still have those machined notches intact, so that the balance doesn't change as the disc wears, it assumess that a disc wears evenly, which most do unless there is an issue with pads/calipers. THAT is why they physically stamp the min thickness on the edge, because the pads don't wear the edge..

Mike

 

[Beedub]

you'll also notice that this cut area varis from disc to disc... some have a very large, some tiny, some None... if this was wear related it would be a standard size across the board, it is for balancing purposes, it has ZERO to do with wear, to measure wear, you measure the overall thickness and your given a minimum thickness engraved on the side usually.

 

[TomK]

It would also make sense that were any balancing be required to the disk that this removal of metal would be within the confines of the minimum thickness level, which would seem to tally with the measurements made.

 

[Nictrix]

So whats correct?
A forum post from 4 years ago or a youtube video from 6 years ago.

Not sure I understand the point of your question. :?

However I believe the video is, as it clearly shows how the marks are made. Plus there are other similar video's of brakes being balanced using this method, all over the internet. :wink:

Sorry my question was about whether VRsteve was correct with his idea that the marks were wear markings or Warmasices original thoughts on balancing which I agree with.
VRsteve, at what point do I get an apology either on here or via PM?

 

[Attilio]

Dual purpose perhaps?

they are for balancing and the width of the cut is chosen to work as a minimum thickness indicator?

everyone would be happy