Originally Posted by
Wanderer
Obviously this is beyond your grasp. If I was a LBS and trying to sell a new chain, I might suggest that. Everything is new, and there is no reason that he HAS TO CHANGE or SHORTEN HIS CHAIN. It will work just fine the way it is, and he can even go back to the other cassette whenever he likes, without doing anything to his chain. And it will still work.
You only have to shorten/lengthen a chain, when the derailleur can no longer handle the extra or shorter length. In this case, this is not the case - the derailleur will handle it fine. The proof is that it is already handling those gearing ranges, in the OEM cassette.
Why try to make something that is already easy, so hard?
Get a grip, I'm done.
Yeah - I can see you've 'mastered' MAXIMUM chain length. There's also MINIMUM chain length and proper rear derailleur tensioning. Correct chain length is more about assuring that the rear derailleur has adequate tension than deciding that its just OK because it doesn't touch the rear derailleur cage.
Based on your viewpoint then obviously no-one should have to lengthen a chain either when going to a cassette with a larger cog and all road bike should be running long cage derailleurs - - just because.
I don't personally worry too much about what goes on in other shops. The one I work in has a reputation for being one of the best in the business. So thanks for all the concern about my credentials - my reputation is already well established here with other professionals in the business. A few Internet comments isn't going to change my life.