It looks like rust on my chain and cassette.
Both were new 5 months (4000 km) ago. The chain is about 60% worn/stretched. I've been riding 5 days/week, 40 km/day, Toronto on mild winter roads, and using only 'dry' lube (i.e. alcohol and teflon) on the chain.
What should I know about that?
I like to keep my bike in good working order, so that it rides very well (but, arriving home each evening after an hour-long commute, I have had no time for bike care: I just lock it, in the laundry room). Is this rust only cosmetic?
Should I use a winter lube? What (product or servicing) should affect/prevent rust on the cassette, if that's necessary?
When I replace the chain (when it's next serviced, perhaps two months from now) should I ask the LBS to replace the cassette again as well?