u/ButterscotchOk5339

Can’t believe the bike dealership let him leave like that

Less than 10 hours on new bike and first ride on trails I suddenly get a grinding sound from the rear wheel while pedalling in anything smaller than 9th gear.

Investigation reveals it’s the derailleur. So after tightening the screw by what feels like an unreasonable amount it’s shifting fine again but I am left wondering what actually happened here? Derailleur went from absolutely fine on several climbs in low gear to suddenly acting up about 30 minutes into the trip.

Also feel like this is a lot of gap in 1st gear?

It’s a SRAM GX AXS if it matters. Bike was put together by the shop that sold it.