What's the story with diamond-cut alloys?

Comhrá

I was in an Audi showroom this morning and was admiring a new A6 with 20" diamond-cut alloys which looked magnificent.

I've heard stories about those diamond-cut wheels being problematic and very hard to keep in as-new condition.

What's the issue with them? Is it the finish or are they more fragile than regular alloys?

Four Phucs Ache

Kerbs.

EndaHonesty

Even without kerbs water ingress causes corrosion.

Not suitable for wet climates IMO.

grogi

tippman1 wrote: »

I was in an Audi showroom this morning and was admiring a new A6 with 20" diamond-cut alloys which looked magnificent.

I've heard stories about those diamond-cut wheels being problematic and very hard to keep in as-new condition.

What's the issue with them? Is it the finish or are they more fragile than regular alloys?

White worm.

endacl

Four Phucs Ache wrote: »

Kerbs.

Drivers

Four Phucs Ache

From what I understand they are cut finer so under a microscope the grain is not as porous or jagged leaving less surface for a good adhesion to a coating which is not as tough as non diamond cut surface from a standard milling bit.

Special Circumstances

Cracks me up that they are on every heap of sh1t going now. And fugly designs too.

Expensive first day, likely to need expensive specialist repairs, and FUGLY. Why?

kadjaaaaaar



Audi do have nice wheel options but the good has been taken out of the "diamond cut" look with some of the awful awful options from other manufacturers IMHO.

jca

Four Phucs Ache wrote: »

From what I understand they are cut finer so under a microscope the grain is not as porous or jagged leaving less surface for a good adhesion to a coating which is not as tough as non diamond cut surface from a standard milling bit.

Wha??? Obviously written by someone who wouldn't know a milling bit if it dropped on his head...

hi5

The problem is they are clear coated over straight metal, once the clear coat is broken there is no primer or zinc to stop corrosion like you would have on normal painted metal, the metal then oxidizes and creeps under the clear coat, given whats known as white worm

Odyssey 2005

Look great in the showroom. Too much grief in everyday use though.

JoeA3

As per above. Looks great (not all the time - there's some horrible designs out there) for the first few weeks/months after the car leaves the showroom. Then it's only a matter of time before whiteworm corrosion sets in and it looks absolutely cat. Even with the most careful ownership, it's almost inevitable. All it takes is a stone chip or two or a careless tyre fitter. Hitting a kerb will obviously speed up the process...

Getting them repaired is a very specialist job. Only 1-2 places in the entire country that I've heard anything good about and even then the quality of the repairs varies, not to mention how long it takes before they look sh1t again.

They're just not a practical wheel finish in most cases imo.