Converted three bikes to singlespeed but haven't hung onto any of them. Last one was an early '90s Cannondale hybrid converted by removing all but one cog from the freehub and adding a surly singleator. That was about 15 years ago and it was my backup bike for a while.
No interest in singlespeed since going 'bent.
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Bacchetta Giro A20, RANS V-Rex, RANS Screamer