Needed a commuter bike for use on low elevation change. Had a mixed bag of parts available. Here's what I did.

• took a 90s giant rincon se with semi vertical dropouts
• bought a cheap crankset on nashbar to replace the riveted one I had
• bought a ss conversion kit also from nashbar to get spacers, tensioner and bmx rear cogs
• found a 42:16 combo that gave me a straight line and played with the chain to get it tight but not too tight of a tension; no tensioner
• other parts: shimano xt rear hub, manitou se fork from an old fisher sugar mtb
• I've been riding it and chain hasn't bound or fell off yet. Granted, I haven't been taking it off road or climbing a lot, but it works well for intended purpose.