A mountain biker loves their brand-new current Grail CF 7 but not its out-of-the-box GRX 1x12: the chain rattles under load on the biggest cogs and drops gears when backpedalling, and it did not settle after the 20–30 km break-in the dealer suggested. Considering a return or an upgrade to an electronic build.
“I just received a brand-new Grail CF 7 with mechanical Shimano GRX 1x12. I actually love the bike itself, but the drivetrain is driving me crazy:”