I did not like the wide variation in the claris 8 speed cassette. I probably could have just changed the cassette from the 11-34, but I plan to keep the bike for a long time so I wanted to upgrade to a more modern group. The 105 r7000 group is also about 2 lbs lighter than the old Claris group. I was also "forced" to upgrade the wheels as the 11 speed cassette would not fit on the stock rim. Altogether, (Shimano group, DT Swiss wheels, ancillary parts and pieces, and labor), it is going to cost me about $1300.00. I am having the work done by an LBS as I do not have the tools necessary and I probably would not have done as good a job. I am expecting to get the bike back tomorrow or Thursday. Can't wait!