If your Tiagra one is a short cage, which may also explain why your chain turn out to be short.
seemed like the only logical issue I can see.
@edscoble started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
If your Tiagra one is a short cage, which may also explain why your chain turn out to be short.
seemed like the only logical issue I can see.