When that happens with my Arroyo, my LBS tightens the chain. It only seems to last a while before it gets noisy again. I bet my LBS will recommend replacing the chain the next time I have my bike serviced. I have ~2000 miles on my Arroyo, so I suspect the chain is somewhat worn/stretched. I plan to take it in for a tune-up sometime this winter, so it will be interesting to see what the LBS recommends.
Tx. I have just over 4K on mine and the chain has been adjusted just once -- never replaced -- so I guess I'll have to bring it in. I was hoping for one of the very few user-serviceable bits on this bike.
Just out of curiosity, does your Arroyo have the Shimano Nexus 8 speed IGH shifter? That is what my 2017 Arroyo has and I noticed on my last few rides that it is making a noise in 8th gear, even if I am just coasting and not pedaling. I am hoping that is an adjustment and not an indication that the IGH is going bad. All the other gears (1 thru 7) are nice and quiet, only 8th gear is noisy. I never really used 8th gear that much anyway and as soon as I realized the noise in 8th gear I avoided shifting beyond 7. Guess I will find out when I take the Arroyo in for service.
Yes, my bike does have the nexus inter 8 hub, but my problem occurs on any gear (which makes sense as the chain doesn't move between gears). I have read in a Shimano manual that the hub fluid should be changed periodically, but no bike shop in my neighborhood does this work. The Shimano kit to do this cost something like $100.