Replacing a Tiagra 9 Speed Cassette

Bill Huang in Duluth, Georgia, USA has been changing bit and pieces on his Specialized Allez bike; he has been up-grading from Shimano Tiagra to Shimano 105 over the years. He wants to know if it would be possible to find a replacement for his Tiagra cassette from one of the other group sets.

Question:
Dear Sir, Madam:

I have a 09 Specialized Allez Compact, which for 2010, named Allez Sport, I personally changed/upgraded almost everything except frame, crank, chain and cassette. It brings a lot of fun and I learnt a lot through the process. It has a 9 speed Tiagra CS-HG50 9, and RD has changed to a 105 short cage. I do not know whether I can find a direct replacement from current/previous 105, Ultegra or Dura Ace group? Crank is compact 50/34. Thank you very much. Bill from Atlanta, GA, USA.

Hi Bill.

It’s great to be able to look after your own bike and the lessons learned at home can help you out when something goes wrong on the road.

To answer your question; yes you should be able to find a replacement 9 speed cassette for your Tiagra. The older Shimano Tiagra, 105, Ultegra and Dura-Ace 9 speed cassettes were interchangeable as the splines on the hubs were the same throughout, this also includes the MTB cassettes; XT and the cheaper HG 50 and HG 80.

The cassette that you have has different size splines on the inside that match the different size grooves on the hub. The older cassettes had splines that were all the same size, but this changed over the years. Do a search on your computer and you will find quite a few available Shimano 9 speed cassettes that will suit you.