Originally Posted by
Ric Toronto
Thanks. My greater question is about the ability of the Vitus frame to accomodate. In past there were some who thought the Ultegra 10 spd would not fit, though it did and has been good. I have more research to do before buying parts
The older Vitus frame should have no problem working with Shimano or Shimano-compatible BSA-threaded outboard bearings. A Tiagra 4600 triple crankset will work with your 6700 STIs if they are for triple. But if you have the short-cage rear derailleur, it will not take up enough chain.
Whatever you do about the crank, you can use any Shimano 9-speed MTB rear derailleur for extra chain take-up with a 10-speed chain and 6700 STI levers. The least expensive, least invasive way to go would be the MTB RD with a wide-range 10-speed cassette (11-32 or 11-34) and compact double (50-34) crankset. If you really want the triple, then a full Tiagra 4600 would be the most direct way to get there.