After browsing the Park Tools website, I began looking at my bike and it looks exactly like this between the rear derailleur and where the cable enters the seat stay. Does the last section of housing look short - this is how it came from the factory? I am getting ready to replace the cable and housing and wanted to make sure I cut it to the right length. The only thing that stops me from making it longer is that Kestrel must have some reason for length that is installed. Thanks.
I agree with Retro, (I usually do, and if I don't I am the one that is generally wrong, but that is another story). The rule of thumb I use if it is shifting OK, I cut the new cables the same length.
I just installed the cables on a new build I am doing (waiting for one more part otherwise I would be riding) and I did something I always do, I cut the housings too long. The rational is I can always cut it shorter. However, I have a drawer full of housings!! I should try and cut them the proper size to start and if it binds I can just throw the housing away and start over. I just don't learn.
Truth is there probably is an ideal length but there seems to be quite a large acceptable variance.