These brake pads not as safe as OEM?

Question

94 Sentra gets first set of brake pads since new, chose Wearever Gold Premium Semi-metallic Pads from AAP because they were advertised as OE. After installing, started thinking about the major angle of pad material (missing) at each end of each pad, compared to the original pads.

If you look closely at the image on this link, you will notice the surface area of contact with the rotor is significantly smaller than an OEM disc brake pad:

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have to "hover over the image to zoom in" and look closely to see the detail of the missing pad material. Since I propose that the significantly reduced area of disc pad materal, that is in contact with the rotor, from each side of the rotor, makes these pads less safe in emergency stopping situations, I do not understand how these can be advertised as OE. I interpret that this means that stopping distance, in emergency situations, will be increased significantly.

I submitted a review for these pads on AAP's website, but am not sure that they will allow my review.

John Henderson · Accepted Answer

installing, started thinking about the major angle of pad material (missing) at

area of contact with the rotor is significantly smaller than an OEM disc brake pad:

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You have to "hover over the image to zoom in" and look closely to see the > detail of the missing pad material.>

I'm not clear how the reduced contact area caused by the chamfer can reduce braking performance.

If a certain force is applied to the pad, against the rotor, then the pressure per unit area is increased proportionally. Less area means more pressure per unit of contact area. And the braking force remains the same.

The chamfer on new pads is there for a reason, and will be gone when it's time to replace the pads.

John

whois · Answer

Take an extreme example: If the OEM pads had 8 square inches ofpad material on each side of the rotor and new pads had 1 squareinch of pad material on each side of the rotor, for a given force onthe brake pedal, wouldn't the stopping power be significantly lesson the latter?

John Henderson · Answer

Not unless the smaller contact area resulted in another factorcoming into play - like local overheating.John

AS · Answer

The braking force is the product of the normal force applied to the pad against the rotor and a friction constant determined by the rotor and pad surfaces and materials. So the braking force should not be diminished in theory.

The fact is that the pad surface is going to overheat as John suggested and that the smaller contact surface will result in more wear for both the pad and rotor.

For years I use dealer brake parts only. Saves me time, aggravation and uncertainty.

AS

snipped-for-privacy@yahoo.com wrote:

installing, started thinking about the major angle of pad material (missing) at

area of contact with the rotor is significantly smaller than an OEM disc brake pad:

formatting link

You have to "hover over the image to zoom in" and look closely to see the > detail of the missing pad material.>

John Henderson · Answer

I should mention then pressure is minimal, friction can be significantly affected by surface area (more area, more friction). But that's not relevant to automotive braking.

As far as chamfer is concerned, here's a short article mentioning how it might be a desirable aspect of pad design:

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John

These brake pads not as safe as OEM?

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