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MadDog70

Brake squeak every morning

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Turbocharged

if you can be sure that the guys did not touch your brake system, the only plausible explanation is this:

 

When you up 2 inches, unless you go for superlight forged rims, your rim+tyre mass is going to increase and most of this increase in mass is distributed more to the outer part (think wider low profile tyres to maintain the same rolling diameter)

 

This increase in mass on the outer part of the rim+tyre combo along with increased rolling resistance (bigger rubber to road contact patch) is going to increase your momentum/inertia. Your engine will spend energy getting the new rims+tyres up to speed and conversely your brakes will work extra hard to shed the speed.

 

Previously, on your original set of rims+tyres, the amount of pressure on your foot brake pedal translate to a defined amount of pressure the brake pad is being applied onto the rotor surface. Now on this new set of rims+tyres, the amount of pressure applied from the brake pad to the rotor surface may be the same, but now the rotor wants to rotate forward more than previously, causing the brake pad contact surface to "slide" against the rotor giving squeeks. When warmed up, the brake pad is "stickier", so the squeekiness is gone.

 

There you have it, my 5 min thesis on the holy grail.

 

Good thesis.

 

I summarize: bigger rim means more heavy, so need more brake power to stop the car. Since you press the brake the same way, there isn't enough brake power so got the squeaking sound.

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Supersonic

I thought it's becoz of the uneven surface of the rotors?

 

But some "sports" brake pads will squeal no matter what.

Thats what i told my friends when they say my brakes are squealling.....racing mar.....F1 and motogp all like that wan.... [laugh]  [laugh]  [laugh]  [laugh]

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5th Gear (edited)

Yours very brief. Here take a look at what this Ph.D. thesis on brake squeal from Imperial College has done and come back in 3 years time 

http://www.imperial.ac.uk/media/imperial-college/research-centres-and-groups/dynamics/40069710.PDF

 

 

Good thesis.

 

I summarize: bigger rim means more heavy, so need more brake power to stop the car. Since you press the brake the same way, there isn't enough brake power so got the squeaking sound.

 

Edited by EricChan

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5th Gear

apply some copper grease on the back of the pads.. if all else fails, change the pads to new ones and apply the grease on the back..

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5th Gear (edited)

apply some copper grease on the back of the pads.. if all else fails, change the pads to new ones and apply the grease on the back..

If you look closely Brake pads do have a damping material integral to it at the back . Point is new pads and old pads can squeal and it is fugitive , sometimes it happens sometimes it doesn't ...and yes chaos theory have also been looked into ...

Here's another paper (by a German group )

http://www.eurobrake.net/programme/technical-programme/EB2016-SVM-004.pdf

Edited by EricChan

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Turbocharged

If you look closely Brake pads do have a damping material integral to it at the back . Point is new pads and old pads can squeal and it is fugitive , sometimes it happens sometimes it doesn't ...and yes chaos theory have also been looked into ...

Here's another paper (by a German group )

http://www.eurobrake.net/programme/technical-programme/EB2016-SVM-004.pdf

 

Bro, I think the papers are informative, but what the TS need are solutions

 

Do you have (in short) practical solutions for him or others who may have the same problem after changing rims?

 

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5th Gear (edited)

Bro, I think the papers are informative, but what the TS need are solutions

 

Do you have (in short) practical solutions for him or others who may have the same problem after changing rims?

 

The point is this: There is no practical solution ..

The solution is to live with it. It is folly to think it can go away with changing this and that , upgrading . downgrading the size etc.

That's what this holy grail is...nobody has been successful in doing so (they have to deal with a lot of warranty claims because customers perceived there is something wrong when new brakes squeal and the car and brake companies themselves can't do anything practical about them when brakes squeal)

Edited by EricChan

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Turbocharged

I half wish @EricChan was kidding about the whole thesis thing... [dizzy]

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2nd Gear

Ever since I changed to bigger rims, my brakes start to squeak every morning when I start the car. It goes away after a few brakings. I doubt changing rims make this noise. Anyone can advise what could be the problem? Thx

 

http://www.mycarforum.com/topic/2608400-brake-pads/?p=5762439

 

Are you using after market brake pads or original?

 

I faced similar problem. Howver, I did not upgrade rims size. Using stock rims.

 

I have since changed to original brake pads 2 weeks back. No more squeaking sound.

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Neutral Newbie

could be wear and tear of the brake rotors... mechanic once told me not to delay in changing brake pads as it might affect the rotor as near the end, it will be uneven wear... not too sure but it kinda makes sense

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Twincharged

 

A secret that many do not know that can keep your brake quiet.

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4th Gear

Need some guru advice.

Some background.

 

1) My brakes has intermittent squeaking

2) My brakes has intermittent whirring noise

3) This is a Merc E-class

4) I sent it in to C&C for checks last month, and they claim to have serviced the brakes. Issues (1) and (2) did not go away.

 

The below is photos of my brake rotors just 9 hours apart. 

Bright and shiny when I drove to office, and totally brown when I knock off.

Is this normal? Is this what is contributing to my above 2 noise problems?

 

post-50942-0-94376300-1491017368_thumb.jpgpost-50942-0-09192300-1491017377_thumb.jpgpost-50942-0-92579100-1491017384_thumb.jpg

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6th Gear

Need some guru advice.

Some background.

 

1) My brakes has intermittent squeaking

2) My brakes has intermittent whirring noise

3) This is a Merc E-class

4) I sent it in to C&C for checks last month, and they claim to have serviced the brakes. Issues (1) and (2) did not go away.

 

The below is photos of my brake rotors just 9 hours apart.

Bright and shiny when I drove to office, and totally brown when I knock off.

Is this normal? Is this what is contributing to my above 2 noise problems?

 

Photo 30-3-17, 9 01 30 AM.jpg Photo 30-3-17, 6 34 53 PM.jpg Photo 30-3-17, 6 35 23 PM.jpg

it is normal, is is not the reason of brake squeaking

 

most of the brake rotors are made of cast iron (except some Lotus with aluminium rotors and those uber expensive carbon ceramic rotors) , they will rust in a blink with the slightest presence of air and water.

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3rd Gear

it is normal, is is not the reason of brake squeaking

 

most of the brake rotors are made of cast iron (except some Lotus with aluminium rotors and those uber expensive carbon ceramic rotors) , they will rust in a blink with the slightest presence of air and water.

yep i have the same prob when parked outdoors esp. they turned brown n very visible after rain n sun. 

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5th Gear

My brakes squeal also.......very loud. funny is only when I'm braking while reversing.

 

New rotor, new brake pad. All original. Skim brake pad no use.

 

Mechanic still say sometimes original brake pad not always good. [:p]

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6th Gear

yep i have the same prob when parked outdoors esp. they turned brown n very visible after rain n sun.

those are surface rust, brake pads will rub it away on the first application of the drive.

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6th Gear (edited)

those high pressure washers at car wash will wash away pad grease by overzealous car wash guy aiming it at the brake calipers.

 

That's why the brakes were quiet for a while after the mechanic greased them and become noisy again after a while (a few car washes actually)

Edited by Phang

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3rd Gear

those are surface rust, brake pads will rub it away on the first application of the drive.

true!!! haha...ntg to worry abt lo...at first i tot the rotor rusted...brand new ones some more...haha got a scare then realise they r just brake dust....gone after driving off..

My brakes squeal also.......very loud. funny is only when I'm braking while reversing.

 

New rotor, new brake pad. All original. Skim brake pad no use.

 

Mechanic still say sometimes original brake pad not always good. [:p]

ya lor...once in a while will get those squeals...either reversing brake or heavy traffic brake...gotten used to it...

 

after mkt brakes also have le at times...

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