Hi I have a Giant Explore E +3. I am surprised by how noisy the drive system is. It seems like it is less noticeable when you have shifted up to say 5th gear. It is very noticeable at lower gears. It has a sound similar to that of loud/aggressive tires. I have never noticed it in my wife's Bosh drive Trek Verve 3+. I assume it is like some sort of clutch with the drive system. I ride almost exclusively in the Eco mode. I'll have to experiment with other assist levels to see if it changes/goes away. I just want to make sure that there is nothing going on that I could damage anything. Maybe the Yamaha is just a bit loud? Thanks.