Originally Posted by gauvins

Glad this was brought up.

A couple of observations:

(1) The conversation on chain wear is almost entirely focused on stretch and ignores roller wear and/or roller-to-cog wear. I suspect that this is in part because stretch is more easily measured and that roller-to-cog wear usually happens at a slower rate.

(2) Another thread made the observation that sediments at the bottom of solvent jars used to clean chains is magnetic. In my experience, this gunk is almost exclusively made of metal particles -- I was able to remove all sediments from a jar using rare earth magnets. So the argument that the stretch part of wear is caused by road dirt appears to be questionable.

(3) I can see how sand can wreak havoc in no time on cogs and rollers, especially if silica particulates are "glued" to the drivetrain by thick oil. As @FBinNY observes, one strategy is to rely on high viscosity lubricants to care for the pin-plate interface, and to wipe excess oil to prevent gunk from sticking to the outside (roller and cogs). But then, the chain would run dry over the chainrings and sprockets and would wear at a faster rate than it would if it were lubricated. One approach might be to use a complementary lubrication method for cassettes and chainrings. Another might be to let the rollers run as dry as possible on the cogs on the basis that wear rates are low and that lubrication will not change things significantly.