Will a Shimano 105, 9 or 10 speed cassette fit on my HG 50 hub?
I currently have an 8 speed cassette. Also, will I need a new chain as well? I am trying to go from a 12-25 to an 11-25
I do believe that the 9 and 10 should fit the 8 cassette. I don’t want you to quote me on that, but I’d bet a dollar or two that it will fit. You can run the 8 chain, but it will be thicker than the 9-10 since they have more sprockets, and are going on the same size cassette hub. If you run the 8 chain it may skip, and will not run smooth. Also, It is preferable to wear (age) parts together when possible. If you have a fairly nice, and fairly new drive and the chain brakes all of the time, then you have to get a new one and can’t wear them together. It just runs the best when the chain, coggs, and rings wear into each other. If I were upgrading to more speeds, I’d get the shifters, the chain, the cassette, and a new crankset, or new rings for my current crank set if possible.
Shimano Ultegra 50-34 crankset