Aluminium corrosion in a carbon frame?

Discuss light weight issues concerning road bikes & parts.
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by wilwil

The paint is falling off all round the aluminium cable entrances on a carbon Bianchi Infinito, exposing significant corrosion. Is the frame a write off?

by Weenie

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by topflightpro

Probably not.

I had a Cannondale System 6. There was a ton of corrosion where the carbon and aluminum tubing met at the BB. I rode it for several years like that, with the corrosion continually worsening. It was still going strong after 8 years, until I got hit by a car.

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by sungod


unless the cf has been damaged (al corrosion product takes up more volume) it should be ok

cf/al interface can suffer from galvanic corrosion if moisture gets in, the al loses

you can apply some acf-50 to treat the corrosion and held prevent it worsening, re-apply every year or so, more often if it's ridden in wet weather a lot

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by wilwil


Posts: 170
Joined: Thu Sep 23, 2010 5:47 pm

by wilwil

Hopefully you can see the picture Ive posted. I have a feeling the gear cable ports will do the same judging by the cracking.

I now notice there is probably corrosion round the BB and the paint is bubbling round the rear drop outs.

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by Calnago

Are you the original owner? If so, I would see what Bianchi might do for you, regardless of whether it's still under warranty or not.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

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by chris8382

I had similar galvanic corrosion on the rear dropout of my Colnago C40. In that case, with the corrosion affecting structural integrity of the frame, I had to have the dropout replaced with a new steel hangar. Not cheap, but the frame was much improved. In your case, this aluminum cable guide/insert is not can probably treat it as described above and then continue to enjoy the frame for years.
Road: Colnago C50
Cross: Ridley X-Fire
Tri:Trek SC 9.8

by Weenie

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