When pedaling with a decent amount of force a very loud creaking sound can be heard coming from the bottom bracket area (it is very loud when standing on the pedals). It makes a creaking noise on each foot's down stroke. So with both feet pedaling equals two creaks per full revolution. If I unclip either foot and pedal with only one foot, a creaking noise will be heard once per revolution (on the down stroke of the pedaling foot). If I pedal softly, no noise is heard.
Things that I have done so far, yet the problem remains:
Changing pedals, regreasing their threads and making sure they are tightened.
Tightening chaining bolts.
Replacing the actual crankset.
Taking the crankset out, cleaning all the old grease and regreasing.
Making sure the crank arm is tightened correctly.
Is there anything left besides it being the bottom bracket causing the problem? I haven't had a chance to inspect that yet because it's a pressfit and I don't have the proper tools to take it out and reinsert it.
Turns out it was the rear skewer of all things causing the creaking! It seemed like it was from the bottom bracket area because it was in sync with my pedalling but I put a dab of grease near the contact points of the skewers and the noise is gone.
So if anyone else is having similar problems, check your skewers first because it's a lot easier than taking your cranks and bottom bracket apart.
Frame damage (e.g. cracks) can cause creaking too. Since you said it happens while standing, that eliminates the seat post + saddle (which are often causes of creaking which are attributed to the bottom bracket). You've also eliminated the crankset+pedals.
Pressfit systems are notorious for having creaks, so it's likely the bottom bracket (to the point where its considered "normal" in some cases). Given how much tools for dealing with pressfit cost, it's probably going to mean going to a shop.
Had exactly the same thing. I took off the chainring and cranks and regreased and tightened everything. Still creaking. Took off the pedals and refreshed and cleaned them up and tightened them back on, still creaking. Eventually I found it was the rear derailleur hanger bolt was slightly loose and was creaking against the frame, grease and tighten and noise is gone, relief. Hope this helps someone.
The proper tools shouldn't cost more than £60. If you think you'll be needing them in the future then it may be worth while investing in them as £60 is roughly the cost of having a shop do it twice.
If you don't want to buy the correct tools you can knock the bearings out easily enough with a block of wood and a hammer. Considering this is likely the source of the creaking then I wouldn't worry too much about damaging the BB further during removal. Reinstalling the new BB can be done with a length of threaded rod, some large washers and some nuts.
Do you know which style of pressfit BB you have? PF30, BB86 etc? You should be able to find the tools you need locally.