I just picked up an older bike, with friction shifters. Above the bottom bracket, the RD cable runs, it has no sheath, instead rubbing on some sort of metal clip (so as to make the bend). It rusted, and now the cable has snapped a few strands. Can I buy a cheapie cable from wallyworld, and reuse the cable sheaths? I don't think they rusted inside (when I shifted to a different gear, the cable looked shiny--bike appears to have been hardly ridden, just stored for years), so I figure, just reuse them.