# carbon wheels squeals when braking



## rlim (Oct 28, 2007)

Is it common for carbon wheels to squeal when braking? I went for an outing with the local bike club and was quite embarrassed whenever I brake as it squeals like a pig being slaughtered. The brakes are Campy Chorus with Kool Stop carbon pads. The wheels are FLIT. I’m wondering if switching brand will make a difference.


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## wetpaint (Oct 12, 2008)

Toeing in the brake pads will make a HUGE difference. With my brake pads toed in a touch, I can't make them squeal. I've also found Swiss Stop Yellows to make less noise than other brands also. I would try toeing them in before buying new pads though.


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## RC28 (May 9, 2002)

rlim said:


> Is it common for carbon wheels to squeal when braking? I went for an outing with the local bike club and was quite embarrassed whenever I brake as it squeals like a pig being slaughtered. The brakes are Campy Chorus with Kool Stop carbon pads. The wheels are FLIT. I’m wondering if switching brand will make a difference.


Yes, it's common.

Yes, it depends on the pad used. SwissStop Yellows are the best at minimizing squealing. Don't forget to properly toe in your brakes as well as the previous poster said.


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## zac (Aug 5, 2005)

Common yes, and more particularly when it is colder out. 

However, squealing is a symptom of a curable problem. As had been said, toeing the pads in will help, and should eliminate the squeal...but that is really a band-aid approach and the squeal will eventually return as the pads wear. Chances are something is not tight enough causing the system to resonate and produce that high frequency squeal.

Make sure your pivot bolts are torqued to maximum spec. Make sure your pad holder anchor bolts are torqued to maximum spec. Next if you have slide in pads into the holders, rub a little soft wax behind the pad (on the holder side only, being careful not to get it on the wheel side) and reinsert in the holder. Make sure it is snug. Now you should be able to set your pads dead flush with your wheel rims and not have any squeal nor pulse. Also set the pivot (or lateral adjustment bolt) so that the calipers engage both sides of the rim at the exact same time. Squealing usually happens in hard braking conditions, and flexing the wheel off center will induce the vibrations more readily.

HTH
zac


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## JimP (Dec 18, 2001)

Another reason for squealing is a rubber buildup on the rim. The brake pads actually melt and leave a deposit on the rim. This can be cleaned off with a green scrub pad or 400 grit wet-or-dry sandpaper and water.


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## cxwrench (Nov 9, 2004)

JimP said:


> Another reason for squealing is a rubber buildup on the rim. The brake pads actually melt and leave a deposit on the rim. This can be cleaned off with a green scrub pad or 400 grit wet-or-dry sandpaper and water.


or lacquer thinner on a rag, and you won't have to worry about sanding down your $$$ carbon wheels.


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## rlim (Oct 28, 2007)

Thanks everyone .. I'll adjust the toe-in as well as remove any rubber residue off the rim. I've also rechecked and tighened the brakes to ensure they torqued to spec. 

It's unbelivable how soft the brake compound is as I can see the rubber buildup on the rim as well as little pieces of rubber collecting at the tip of the pads. 

More update to follow when the weather clears up and I hit the road again ...


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## rlim (Oct 28, 2007)

darn ... with my luck, the weather hasn't been cooperating last couple of days ... snow!! They forecasted weather warming up Thursday through to the weekend ... 

I've completed all the adjustments suggested ... I cleaned the rims with Goof-Off and its unbelievable how easily it removed the rubber residue. The wheels look practically brand new!!


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