Every once in a while when I'm in my lowest/slowest rear gears (no matter the front gear), I will have issues shifting and, on occasion, the bike will start shifting on it's own. Two bike shops have looked the bike over and adjusted it to a point now where it hardly ever happens but it always comes back. It's been in the shop for this 4 times. At the minimum I experience these issues 1-2 times a week. At their worst it's any time I'm in the gears period.

I have about 300 miles on my bike now so I'm curious to know if this is an issue with the shifting components being of a lower level variety or if this is still a new bike issue? I had the issues immediately. I'm considering upgrading the DRs if this is just going to be something that continues to happen with the components on the bike. I'm at around 200lbs and not in the best shape (hence the reason for buying the bike) and it's killing me on steep hills when it does this.

I also experienced my first 40mph downhill that comes to a sharp turn. I see why people like disc brakes on bikes so much now after trying to slow down!