They are yellow zinc chromate plated - so they are likely cracking due to hydrogen embrittlement. Plating wasn't done properly - we see that frequently with "offshore" hardware.
Embitterment is right. Tried again on a wheel that was off the car so I could get to both sides of the clip. Broke four more. Just pulling up slightly with a pair of needle nosed pliers will snap the finger clean off. Calling the company for RMA. These are not working and I doubt they ever will.
Do be cautious all those thinking this is the source of these little boogers.
Well damn.. Glad to find this out before I ordered a bunch at any rate...
I thought that would be needed, since there was some joy in finding them on line. Finding they need to be returned = NO Joy.
i pull them darned clips out of every old VW wheel i come across.. i have come up with one full set and a few left over spares in my 3-4 years of looking..
If you want to save some of the plated ones that are failing, you might be able to bake them. Yellow zinc chromate plated parts are supposed to be baked at (I believe) 500 degrees F for 8 hours within 24 hours of the plating process. It might be possible to salvage some if you haven't stressed them yet by trying to install them. Once the cracks are there there is no way to save them. Worth a shot if you have some more.
I ordered 16 and will be sending them all back as a dissatisfied customer. For what they cost I could have purchased one good looking alloy rim. Still debating that route and would sell the caps I have to offset the price.