Is this white worm / corrosion?

Soldato
Joined
5 Jul 2006
Posts
2,737
Hi Guys,

I recently bought my first car (2016 VW Scirocco R) about 3 weeks ago which has been great, however I have started to notice some sort of white substance forming on the wheels (19" Cadiz Alloys). This is more noticable on one of the wheels in particular, however there are smaller marks which look similar starting to appear on the others also.

They don't feel like scratches at all and feel like small bumps forming underneath the top layer of the alloy wheels. After a quick google I think this might be the start of some white worm / corrosion and would appreciate some feedback.

I was informed that these were new alloys fitted to the car so I wouldn't expect this to happen in such a short period of time.

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Last edited:
Soldato
Joined
28 Dec 2007
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11,547
Location
Sheffield
I was informed that these were new wheels fitted to the car so I wouldn't expect this to happen in such a short period of time.

My GF's 2016 Abarth 500 has had 3 wheels replaced under warranty so far due to corrosion on the diamond cut. Honestly I'd just suggest having them refurbed in a solid colour to avoid future aggro.
 
Soldato
Joined
27 Mar 2013
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9,121
My wife's diamond cut wheels look similar. What happened with hers was moisture gets under the laquer on an edge where it's been cut and starts peeling it away. Hers look appalling.
 
Associate
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20 Aug 2008
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Stafford
Yep, whiteworm and worth a warranty trip to the dealer. I have had 3 of the 4 GTI wheels replaced because of it and they have started going again. They will try to fob you off saying it is stone chips causing it but push them as it is a known problem with their low quality lacquer on diamond cut wheels.
 
Associate
Joined
18 Jan 2004
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Somewhere
the wonder of diamond cut wheels. would never own another car with them.

it only takes a small chip in the lacquer to let air seep in. air corrodes the exposed aluminium creating the ali oxide you can see. This then keeps progressing underneath the lacquer.

Warranty repair, or get them fully painted.
 
Man of Honour
Joined
17 Oct 2002
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159,534
Why do manufacturers persist with this finish? It always leads to problems and is hardly leagues better looking than a properly painted finish. It must cost them a fortune in warranty claims.
 
Soldato
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3 Jun 2012
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10,803
They look nice, but unfortunately they become ruined fast.

Either get them replaced under warranty or have the set powder coated.
 
Man of Honour
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21 Nov 2004
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44,880
My diamond cut wheels look shocking. Was going to get them done, decided against it, then managed to whack them again. Would avoid diamond cut wheels if possible in future.
 
Soldato
Joined
13 Feb 2003
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2,813
Location
Sheffield
often sign of a bad refurb on diamond cut wheels

Sure, but our wheel guy repairs dozens of these a week that have never been touched since leaving the factory so it isn't limited to poor refurb work.

It's just a product of the poor system used. I'm no chemist but it just doesn't seem possible (or economical) to produce a clearcoat that adheres well enough to bare aluminium to prevent that kind of creeping corrosion.

As others have said, I'd much rather manufacturers put this fad behind them and move back to proper powder or wet coated wheels, although it'll dramatically reduce how much work our wheel guy has :D
 
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