Hi everyone, so I was in the garage with my sis' bf talking bike stuff, and a question came up regarding his gearing setup.
He currently has a 105 rear derailer with tiagra shifters... His current cassette is a 9 speed. He was wondering if he was able to throw on a 10 speed cassette and still have the shifters be able to reach the 10th cog. He wants to be able to drop into a lower gear for climbing, and if anything just have the options for another cog setting.
I also mentioned to him that he would be able to find another 9 speed cassette with a greater tooth range, so I basically have the answer, but for the sake of another opinion we were just wondering if the tiagra shifters would work. Thanks in advance