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  1. #1
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    Brake pad new design?

    So I bought some Brembo front brake pads for my Nissan following a service at the main dealer when during the “complimentary health check”they advised they be changed because they were down to 3mm. He said they start off at 8mm. If I didn’t change them now I risk damaging the discs and it would be a lot more expensive. Naturally at £135 I declined especially as there’s still some more life left in them and they are fitted with the metal brake wear indicator clips which will “tinkle” when they get down to just over a mm. I bought Brembo because they are a good make and they were on offer at just over £50. I know I could have got lesser well known makes for less. Anyway to get to the point finally these Brembo pads are of a design that I’ve never seen before and wonder if anyone else has. The pads have an overall thickness of about 9mm but they taper at both ends for about 25% of their length to about 5mm. This means that the total area of the pads is not being used until 4mm of wear has taken place. I hope I’ve explained that sufficiently well to ask the reason behind this particular design.
    Dek

  2. #2
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    That does sound like a fairly aggressive taper, but they (try to) stop squeal - whether or not the pad needs a taper depends on the material they're made out of but the idea is to stop the leading edge of the pad from contacting the disk before the rest of the pad and causing a twisting force on the pad.

    Actually .. can't remember the last time I saw a pad without a chamfer but that could be because I haven't bought OE pads in a while!
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  3. #3
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    Quote Originally Posted by aaronjb View Post
    That does sound like a fairly aggressive taper, but they (try to) stop squeal - whether or not the pad needs a taper depends on the material they're made out of but the idea is to stop the leading edge of the pad from contacting the disk before the rest of the pad and causing a twisting force on the pad.

    Actually .. can't remember the last time I saw a pad without a chamfer but that could be because I haven't bought OE pads in a while!
    You’re right Aaron it is aggressive. It means that when the pads have worn to the start of the chamfer (wear of 4mm) the contact area will slowly increase to give a final contact area increase of about 25%. It doesn’t make sense to me. Why would you want to increase the braking efficiency when the pads are about half worn? It begs the question is the initial contact area of 75% of the final total sufficient?
    Dek

  4. #4
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    2 reasons for the taper.

    1. To stop the irritating squeele that used to be hand sanded by the good old boy mechanic but is now all elf ‘n’ safety constrained.
    2. Aggressive ramp means they wear out faster and you buy more pads! The gift that keeps giving
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  5. #5
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    Quote Originally Posted by Happy Jim View Post
    2 reasons for the taper.

    1. To stop the irritating squeele that used to be hand sanded by the good old boy mechanic but is now all elf ‘n’ safety constrained.
    2. Aggressive ramp means they wear out faster and you buy more pads! The gift that keeps giving
    I think it’s more likely to be 2 Jim. To stop squeal you would only have to chamfer the edges a little. I’ve since been on the Brembo website and seen they advertise Xtra pads, which have this type of chamfer, for performance but not track use which doesn’t need a disc change. This suggests they are a softish pad and likely to have a high wear rate as you say. I’ve emailed them to ask them about the rationale. Will report back if I get a reply. Just thought this is really going to cause problems with future services when the health check measures pad wear at the extremity!
    Dek

  6. #6
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    So I got the following reply from Brembo in Italy:

    “We inform you that the chamfer is required for increasing the comfort while braking.
    It is not related to a change in performance or early pads wear.”

    Any Italians out there that can interpret for me?
    Dek

  7. #7
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    I'm not Italian but I think it says

    “We inform you that the chamfer is required for increasing the comfort while braking.
    It is not related to a change in performance or early pads wear.”
    Cheers

    Myles D-W

  8. #8
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    Quote Originally Posted by mylesdw View Post
    I'm not Italian but I think it says

    “We inform you that the chamfer is required for increasing the comfort while braking.
    It is not related to a change in performance or early pads wear.”
    Yes I can read as well. But what does it mean?
    Dek

  9. #9
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    That'll be Italian for reduced squeal and judder. LOL!

    Joking aside though, I thought better brakes came with bigger pad area contact on the disc?
    Otherwise why do we buy bigger discs and callipers?
    I guess bigger callipers with more piston area will give more clamping force.

    The taper reduces the contact area until the pad is nearly worn out.
    Last edited by kdavies3; 19-10-21 at 09:36 AM.
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  10. #10
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    Quote Originally Posted by kdavies3 View Post
    That'll be Italian for reduced squeal and judder. LOL!

    Joking aside though, I thought better brakes came with bigger pad area contact on the disc?
    Otherwise why do we buy bigger discs and callipers?
    I guess bigger callipers with more piston area will give more clamping force.

    The taper reduces the contact area until the pad is nearly worn out.
    Here's my speculation:

    The advantage of bigger discs is that the pads are further away from the axle centerline, so more leverage is exerted. Ths gives more stopping power for the same pedal force.

    The frictional force should not be dependant on pad area as the force to overcome friction, f = uF and is thus independent of surface area. However, a larger pad does help spread the heat out over the pad area making it more efficient and less susceptible to brake fade.

    As I have fairly poor brakes I made a number of changes, one of them being installing calipers with a larger diameter piston. This increases the force against the pads with the same psi line pressure.

    Interestingly, I did investigate an aftermarket caliper with twin pistons. Total piston area was less than my original single piston unit, however those that used this twin piston calipers reported a better braking experience. Why? Because the two smaller pistons are locate further away from the axle center line than the single piston, and thus better braking is gained by improved leverage.

    Just my two cents worth....
    John

    “A prudent person profits from personal experience, a wise one from the experience of others.”

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