I like the way 4x looks, but I'm not aware of a functional difference. Or, rather, if there is one it's too subtle for me to notice while riding, anyway.
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1964 JRJ (Bob Jackson), 1973 Wes Mason, 1974 Raleigh Gran Sport, 1986 Schwinn High Sierra, 2000ish Colian (Colin Laing), 2011 Dick Chafe, 2013 Velo Orange Pass Hunter