Convinced that it was at least not harmful to o-rings, before building a dedicated oiler I decided to test the WD40 on a trip. I wanted a way to quickly lube the chain during a SS2000 from East Texas to the west coast, so I fashioned a pouch on the front of my left pannier to hold the can and I gave the exposed parts of the chain a liberal application at every gas stop. It took seconds and not only did the chain never run dry, it required NO ADJUSTMENT for the entire 4,848 mile trip! And the chain was not new. The EK brand 530zzz x-ring rated at 11,000# had over 10k on it when I started. I carried a can of Blue Label PJ-1 in case I encountered rain.