Al,
Actually, a good chain lube should do more than prevent rust. It should keep the x-rings soft and keep them from drying out. Also, a film-type lube should provide some lubrication between the rollers and the sprocket teeth to prevent wear. A heavier bodied lube does the same thing, but it makes a mess unless you keep after it, and it is more prone to collect dirt and be extruded out of the contact area. ( I love it when I talk like that...
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