Originally Posted by
jonathanf2
On a side note, awhile back I did start a thread about implementing an 11-42t cassette on my 2x GRX equipped bike. I have it tuned now to where shifting is smooth (comparable to my friend's Ultegra bike) and only needs a a slight barrel adjustment after a fairly bumpy ride. It's not within Shimano spec, but being able to ride fast on tarmac and still climb with MTB'ers has made my bike incredibly versatile.
Thats great! I definitely tend to say, to that specific setup, "Don't do it." Only because that is pretty far out of spec, not specifically because it is "impossible." I'm glad you were able to get it tuned. As someone who rides pretty much only carbon hoops now (the only bike without them is my fatty, and it might eventually get them), changing from aluminum to carbon and proper climbing gears will definitely make climbing "easier."
That all said, 650b has it's place, really shining on the rougher stuff (in my experience), and as I stated above, because they just seem to spin up faster.