Anyone seen this on rims?

Especially for light weight issues concerning cyclocross / touring bikes & parts.

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Bergwerk
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by Bergwerk

Today I was giving my bike a good clean in the sun and noticed a pattern of crackles on the rims of my brand new pair of DT SWISS R 24 Disc wheels. Anyone seen this before? Both front and rear have the same pattern all around. And while it is barely discernible in low light, it is very clear in the bright sun. Any reason for alarm?

Image

Same rim under garage lighting.
Image

by Weenie


bm0p700f
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by bm0p700f

If the fim was failing there would be cracks or bulging at a spoke hole. It is crazing in a laquer you are seeing.

joshpeck
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by joshpeck

yikes. Probably just clear coat, but I would warranty if I were in your shoes.

bm0p700f
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by bm0p700f

Don't worry it just the surface finish not the metal that has crazed.

PattiTalks
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by PattiTalks

If you ask me it is the anodizing layer on the aluminium that took some scratches.
You could look for a (larger) scratch on a different place on the rim (because you ride CX there probably will be one) and see if the colour of the material underneath the surface treatment has the same color.

Marin
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by Marin

I think it looks quite cool

DamonRinard
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by DamonRinard

I agree with Patti, that looks like cracking in the anodized finish.

See if DT is rolling the hoops after anodizing. You can tell by looking at the drilled holes: if the wall is silver aluminum, it was drilled after anodizing, and thus probably rolled after anodizing too. Rolling after anodizing could cause that cracking pattern because the rim's spoke face yields in compression during rolling. (Normally the hook yields in tension too, but it isn't evident in your photo.)

Cracks in the anodizing layer act as stress risers and contribute to fatigue cracking with long use. Not to say it'll necessarily happen prematurely - DT might have qualified this rim's fatigue life *with* the surface cracks.

Source: I used to work at Trek as a wheel engineer where we rolled our own extrusions into rims and had an extensive wheel test lab including drum fatigue testing.
Damon Rinard
Engineering Manager, Road Bikes
Cycling Sports Group, Cannondale
Ex-Kestrel, ex-Velomax, ex-Trek, ex-Cervelo

by Weenie


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