I had one of mine do this and I think it came from the sharp edge on the extrusion when I inserted the wheel, the wheel got a little nick in it and then cracked form there. My solution is to file the sharp edges off the extrusion before bringing wheels near it (-:
If you got your wheels from the Openbuilds shop, or one of their Representative outlets, then you should get in touch with them and explain your problem. Obviously under normal situations the wheels should not crack. Our shops will be more than happy to help you sort this problem out. Gray
