I am still working on this as I can not find the ultegra sti 9sp double available on any website. I replaced the 8 speed cassette with an old 9 speed and it fit. What are the chances of going to a 10 speed. If I can use the 10 speed my options for the STI are better. From the time I have put in researching it would have been better to take it to a lbs.