New Bike suddenly noisy after its first cleaning
 

So, after the first 180km on a lot of Gravel roads I decided that it's time for a first cleaning of my new Trek Checkpoint ALR4. So I did my usual bike cleaning procedure which worked uncountable times on my other bike with a Deore/LX drivetrain:
1) Rince of the bike with running water but with low pressure
2) Spray the chain with bike degreaser
3) Let the chain run through two brushes to make it sparkly clean
4) Rince off the chain again
5) let it dry in the sun for about 3 hours
6) relube the chain with an allround chain oil (Kettenwixe) which is somewhere in between a wet and a dry lube.
7) wipe off the access oil after 5 Minutes

Unfortunately when I wanted to do a bike tour today, after a few meters the bike started to make loud and noisy crackling noises with every pedal stroke on both sides - the harder the noisier. Happens in every gear, only while pedaling and also while standing. I already tried putting more lube on the chain, different pedals and taking out the crankset and cleaning it as well as the bottom bracket. I'm completely at a loss here - Only thing I can imagine is that this chain in particular doesn't take well to my cleaning procedure for some reason - it's a KMC X10-1 and came with the bike.

Yes, and the bike stays quiet while backpedaling. It's only happening when I put force on the pedals. Just now I decided to take off the chain (which has a reusable chainlink, fortunately) and putting some force on the pedals without the chain. I could not get any kind of noise out of the bike so I guess that eliminates the bottom bracket as the issue. I also decided to submerge the chain in degreaser. I'll let it sit there over night and will check back next morning. So, in my mind that leaves the chain and maybe the adjustable rear horizontal sliding drop-out. But I'm open to other suggestions as well, of course.

Hmm, I really don't get it. I just took out the chain, rinsed it off, relubed it and tried again, and the clicking noise is unchanged. I suspect it doesn't have anything to do with the chain after all :( I also took out the cassette, gave it a good clean and then put it on with some grease but that also didn't do a thing. Also the sliding rear drop-out is absolutely bomb proof tight and I let it be without trying to tinker with it. Any other ideas of what I could try?

I have had this same exact experience after cleaning a long-neglected greasy chain. The bike ran fine with all that gunk on it, but the minute I cleaned it, all the demons were unleashed. My advice is to never, EVER clean any of the components on your bike. ;)

The first thing I thought of is a freehub body with rusty bearings. Andy

Gravel roads throw up a great deal of grit. The old lube was likely gummy enough to hold the grit in suspension, at least enough to muffle the sounds that you're now hearing. Cleaning the chain freed the grit but didn't remove it.

If it were me, I wouldn't waste time trying to clean the chain again. You're unlikely to get all of the grit out.

Different people have different approaches, including using wax and crock pots, but I've found that what works for me is to install a new chain, run it through a cloth after every ride or so, and then relube when it needs it.

Per chance did you route the chain over the tab on the rear derailleur, rather than under (or behind) as its supposed to be?

Also, when you put the chain back using the quick-link, do you have the quick-link oriented properly? Some need to be in a certain orientation, (smiley face down) and if not, it can be noisy.

I've flushed water/degreaser into my freewheel before. It caused a clacking sound (noisy freewheel). The water worked out shorty and the sound disappeared as quickly as it appeared. If it's your freewheel... you should be able to isolate the noise/source by pedaling while the bike is on a work stand or suspended.

Sounds like you've eliminated the chain as culprit. Have you checked chainring bolts? They make noise when lose and under pedal pressure.

Yes. This seems likely.

Do you really think this is superior to leaving it alone?