Hello Jim. you just say an '80s Absolute but does it index? of course you would need index downtube shifters. also unless you really want to add new cables you can always shorten the older housings and cable. however as I am sure most home mechanics know SIS cables can be difficult to cut without proper tools.
why was it a mistake? while it is not a sought after collector piece there is nothing wrong with any bike that is safe rideable.
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk