Jupestar wrote: ↑19 Dec 2022, 10:48am
In terms of getting 2x with 42t rear. I guess it's a combination of pushing the design spec, and lowering the RD so it can take a larger capacity..
If your RD currently goes to 42T cassette then it will not require any changes to it.
(no lowering needed)
If you decide to go 2x on the chainset then the FD needs to match the chainrings difference and sizes.
The FD has also to have the matching chainline so probably a GRX one.
(Be wary that an FD will only go down so far before it catches the chainstay.)
I do know of someone who did have a set up of manually changing the chain over from one chainring to the other.
(no FD)
With this though there is a chance if you cross chain on big to big the chain can unship from big ring to small on its own.
Not too bad a problem but on one of my bikes it would unship sometimes onto the BB.
With a 2 ring set up the chain has to be long enough to wrap around big ring to big sprocket plus a link. This may require an extra long chain ?