I saw someone filing their new brake pads. I think it was on the leading and trailing edges, at 45 degrees, and only taking the height down by no more than 5-10%. I imagine this helps keep the pad flat on the rotor whilst braking, and helps break in the pads.
Is that sensible? Do some new pads come that way? Anyone care to comment?
Some pads DO come that way.
Some pads come that way, but I can’t see doing it to pads that don’t. Can’t hurt anything that I can see, however, unless one gets too excited with the file.
The chamfer is designed to reduce brake squeal. Some pads will “ring” when at full thickness and reducing the contact length when at full thickness by adding a chamfer can help this. As it wears down the pad no longer “rings” and can take the full length. As other posters here have said, some pads come that way. Some pads have a slot cut in the middle to help this, too. Some mechanics will add their own because they think it will reduce bring-backs for noise.
The Delcos I put on recently were that way.
I never understood the need for the chamfer since better stopping power is had by more pad contacting the rotor surface. Thanks @Mustangman now I know why they are made that way.
I’ll add some of my observations
Over the years, I have not noticed that the chamfers or slots have reduced noise whatsoever
That goes for factory AND aftermarket brakes, semimetallic and ceramic
Some of the best brake pads had no slots and no chamfers, and they were quiet, all the way down until they hit the audible wear indicators
When I see guys chamfering brake pads before installation, I walk far away and laugh, so that the guy can’t hear me.
If it makes the guy feel good, fine
But I don’t chamfer brake pads. I don’t modify brake pads. I install them with shims and brake paste, if applicable
No problems yet
That 10 minutes that those guys spend adding a chamfer, I spend that time getting started on the next job
I’ve always chamfered and slotted pads that did not come that way out of the box. I also don’t think that I’ve ever spent more than 3-4 minutes to chamfer and slot a full set. If it helps one iota in regards to brake function, longevity, and noise issues then it’s 3-4 minutes worth eating is the way I look at it.
EBC (one of the larger brake manufacturing companies) explains far better than I can why chamfering and slotting can help.
Were the pads without the chamfer cheap replacement pads?
@jtsanders I could / did not see detail of the pads being filed. The pads I have are Textar and Porsche (front and rear, respectively, low and high price, respectively)
@JuniorMint
Textar has . . . at times . . . been the OEM for some european auto manufacturers