Ok, but sometimes when your replace only the chain, an unpleasant noise appears the first hundred kilometers
How many teeth on your rear sprocket?
16 teeths and 36 in front (Surly stainless steel) but the noise it seems to be coming from the back..
As chains wear and elongate, the chain links with the inner plates do not elongate but the chain links with outer plates do elongate. More on that here:
https://www.sheldonbrown.com/chain-life.htmlMost people on this forum use a sprocket with 17 teeth, an odd number, thus every sprocket revolution a tooth that had a link with inner plates on it, the next revolution will have a link with outer plates on it. That is because Thorn fits bikes with a 17 tooth sprocket when new.
Rohloff hubs when sold new come with a 16 tooth sprocket, I am also running a 16 tooth sprocket. (For touring, I use the same gearing as you, 36T chainring, 16T sprocket.) Thus as long as you do not change your chain, the chain and sprockets wear to match each other. As a chain elongates and half of the links have an increased space between rollers, some teeth wear more than others.
If you put a new chain on without changing or flipping a sprocket, the teeth that were worn in to match an old chain will take some time to wear into match the new chain.
Also, if you take a worn chain off, clean it and put it back on, if you put it on so that it no longer is on the same teeth, the teeth might not be on the same links and that could cause the chain to be off somewhat.
I cut a small notch into one sprocket tooth and one chainring tooth. Every time I put a chain on the bike, I am careful to always put a link with outer plates on the tooth with a notch. Sometimes it is hard to see the notch, it fills in with grime so I also painted a spot on the sprocket and chainring. This won't solve the issue of noise when you put a new chain on worn teeth, but it may help a little bit.
I ride several different bikes, one has a Rohloff and the others have derailleurs with seven or eight speed cassettes. Most of my miles are on the derailleur bikes. Since I am wearing out eight speed chains on the derailleur bikes and I change those chains more often than you would need to change them on a single speed or IGH hub, I now am putting chains that I wore out on a derailleur bike onto my Rohloff bike to get some more wear before I discard them. Thus, I no longer put new chains on my Rohloff sprocket or chainring.
I got home from a bike tour a week ago with my Rohloff bike. I discarded the chain where I did my tour, did not bring the chain home. It was already quite worn when I started that tour. I will be putting a chain on the Rohloff bike that already meets the definition of worn out from a derailleur bike to get some additional wear on it before I discard it.
Photo attached, several years ago I took this photo before I flipped my sprocket. The tooth on the left has a lot more wear than the tooth on the right.
