Originally Posted by willtsmith_nwi
The contamination often comes for chain lubing. In my classic example, the kid at the bike shop lubes my chain by spraying Finish Line onto the cassette while pedalling backwards. The overspray hits the rotor and contaminates the system the first time the brakes are applied.
Anyone who lubes their chain with an aerosol at the cassette doesn't deserve functioning brakes anyway.
Originally Posted by willtsmith_nwi
The second example is using any "dry" lube which ironically goes on EXTRA wet. The liquid lube splatters as you pedal backwards and gets on the rotor.
Sorry, but I've been using wet and dry lubes for years, and I don't see how this could possibly happen without gross negligence on the part of the lubricator - see above.
Originally Posted by willtsmith_nwi
Actually, I think I need to cut a "rotor shield" out of cardboard for lubing. I had previously bought a Pedro's Chain Keeper, then I switched to a Karate Monkey which requires you to break the chain in order to remove the rear wheel at all. It kinda defeats the whole point of the tool ;-)
It seems Ragnar was right.