trinydex
06-06-2006, 03:07 PM
everyone should understand why brakes/brake squeek/squeal/squeel/make noise/are noisy
think about it like your brake pad is like a violin string, your rotor is like the bow. you're drawing the bow across the string and if there is room to shake then it'll make noise.
if you have air in your lines the squeek will be worse as there's a little more room or give for high amplitude oscillation which is what causes the noise.
what the installation grease does is tries to damp this vibrating out and also to minimize the spaces inbetween surfaces for vibrations to happen.Â*
brake dust makes this issue worse because now you've built up a lot of tiny violin strings and that just means there's more ways to squeek.
why race pads squeel regardless is because they're harder, things that are harder vibrate at a higher frequency and at that point you can't damp them out and it doesn't matter how rigid your setup is, they're gonna oscillate.
In the never ending quest to learn and assist learining in others I've looked for a good paper on brake pads.....
Many get VERY technical and have not enough basic info - but this one I like.
]
Of particular interest
Page 10 - a decription of what pads are generally made of and why.
Page 20-25 or so have some good high magnification pictures of contact plateaus and such.
And as the paper/research is based on understanding squeal - well there is information on that as well.
Things to keep in mind if you do read some of it..
He uses some organic pads in his test -
He uses a floating caliper design -
He is most interested in what cause squeal -
His tests verify/explain quite a few things we sort of know from experience.
Pads work better after break in...
Friction does increase during 1 stopping event after pressure and heat do their job
Once the conditions for squeal are met - it will continue to squeal until those conditions are 'unmet'.Â* Furthermore he finds the oscillation of the pad is where the noise comes from - so changing that resonant frequency somehow is the key to less squeal.Â* Greas can only do that temporarily - perhaps re-us eof your factory shim with or without your OEM pad shim - flip the shim around - modify it in some fashion.Â* That is what you should be looking at if squeal drives you nuts.Â* Changing the rotor surface would sure ly help - but may only be temporary if it reverts back to the noise conditions after wear.
[url]http://www.socalevo.net/gallery/albums/userpics/10991/Mikael%20Eriksson%20Thesis.pdf (http://www.angstrom.uu.se/materials/Tribomaterials/Research/Mikael%20Eriksson%20Thesis.pdf)
think about it like your brake pad is like a violin string, your rotor is like the bow. you're drawing the bow across the string and if there is room to shake then it'll make noise.
if you have air in your lines the squeek will be worse as there's a little more room or give for high amplitude oscillation which is what causes the noise.
what the installation grease does is tries to damp this vibrating out and also to minimize the spaces inbetween surfaces for vibrations to happen.Â*
brake dust makes this issue worse because now you've built up a lot of tiny violin strings and that just means there's more ways to squeek.
why race pads squeel regardless is because they're harder, things that are harder vibrate at a higher frequency and at that point you can't damp them out and it doesn't matter how rigid your setup is, they're gonna oscillate.
In the never ending quest to learn and assist learining in others I've looked for a good paper on brake pads.....
Many get VERY technical and have not enough basic info - but this one I like.
]
Of particular interest
Page 10 - a decription of what pads are generally made of and why.
Page 20-25 or so have some good high magnification pictures of contact plateaus and such.
And as the paper/research is based on understanding squeal - well there is information on that as well.
Things to keep in mind if you do read some of it..
He uses some organic pads in his test -
He uses a floating caliper design -
He is most interested in what cause squeal -
His tests verify/explain quite a few things we sort of know from experience.
Pads work better after break in...
Friction does increase during 1 stopping event after pressure and heat do their job
Once the conditions for squeal are met - it will continue to squeal until those conditions are 'unmet'.Â* Furthermore he finds the oscillation of the pad is where the noise comes from - so changing that resonant frequency somehow is the key to less squeal.Â* Greas can only do that temporarily - perhaps re-us eof your factory shim with or without your OEM pad shim - flip the shim around - modify it in some fashion.Â* That is what you should be looking at if squeal drives you nuts.Â* Changing the rotor surface would sure ly help - but may only be temporary if it reverts back to the noise conditions after wear.
[url]http://www.socalevo.net/gallery/albums/userpics/10991/Mikael%20Eriksson%20Thesis.pdf (http://www.angstrom.uu.se/materials/Tribomaterials/Research/Mikael%20Eriksson%20Thesis.pdf)