BITD? You're referring to the late 80s-early 90s as BITD? Really? There have long been chains of various widths. When freewheels went narrow to squeeze 6 speeds into 120mm dropouts, or 7 speeds into 126mm, there were specifically narrow chains that were required. I do not know how long that lasted, nor if what Shimano is calling "narrow" in the period of these cranks means something else. But if they were all the same for derailleur bikes, then why mark it "For NARROW chains only"?
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1959 Hilton Wrigley Connoisseur (my favorite!)
1963 Hetchins Mountain King
1971 Gitane Tour de France (original owner)
* 1971 Gitane Super Corsa (crashed)
* rebuilt as upright cruiser
1971 Gitane Super Corsa #2 (sweet replacement)
1980 Ritchey Road Touring (The Grail Bike)
1982 Tom Ritchey Everest
(replacing stolen 1981 TR Everest custom)
1982 Tom Ritchey McKinley (touring pickup truck)
1985 ALAN Record (Glued & Screwed. A gift.)