on a club ride a couple of weeks ago one of the riders was having trouble with a rubbing brake. so another rider decided to "back it off" by turning the adjuster barrel in the brake lever !!! . three miles later and and the rider of the adjusted bike tried to change down onto the small ring and nothing happens. this is the start of a 5 minute conversation about how the rider was too obsessive with their cleaning and had caused to mech to jam up and stick, the final nail in the coffin was that one of the really accomplished riders said "yeah, you need to put some 3-in-one on that".
now with me being new to the group my meagre comment of "thingy just locked it off by turning the barrel adjuster" was ignored.
i bit later on and the rider is still having trouble. i manged to get alongside and instruct them to wind the barrel adjuster back in. surprise surprise, the gears were working again !!!!
the point is, you never know who knows what and/or when someone you think is in the know is talking shite and should know better.
its an endless mindfield of opinion verses knowledge verses urban myth verses best guesses