I have this bike in a size 61: 2016 Specialized Diverge A1 (tried posting link to specs and details but I need 10 posts before forum will allow)
The specs say it has a shimano claris crankset and shimano octalink spline. I've been chasing down a creak/click in my bottom bracket area and I've found that I actually have a FSA Gossamer crankset and FSA bottom bracket. Is that normal? The bike was brand new when bought from the bike shop. I've taken the crankset and bottom bracket off, cleaned and re-lubed. Then reinstalled. Significant improvement, but still get the occasional creak or click when pedaling hard. It does have a new chain and cassette and the pedals have been taken off and cleaned and threads greased. I'm almost positive the bottom bracket is the noisemaker seeing there was finally some improvement after re-lubing it. If I decided to replace my crankset and bottom bracket, could I just get the above claris and octalink? Or is the FSA brand "better". I am very obsessive when it comes to my bike (or any vehicle) making a sound it shouldn't! lol. I'd estimate the bike has 2000-2500 miles on it.

Component drift from a published spec list is common enough so spec charts usually have the fine print bellow "specifications are subject to change in BRAND X's push to better performance and a greater value", or some such. Andy

And the fact that the original spec was claris/octalink doesn't mean that those are somehow a better fit and will not give you any problem. Bottom bracket area creaks are notoriously hard to pin down, since a lot of things can make noise that seems to come from that area. 2000 miles seems low for needing to replace a bottom bracket, and since it got better when you cleaned it, it sounds like the noise might be the BB moving in the frame, not any problem with the bearings/internals. I would double-check that the BB is securely in the frame first, then look for other possible noise sources like loose chainring bolts or the cranks not being tight onto the spindle. But that's just guessing.

Based on the original specifications listing an Octalink bottom bracket I assume the frame is English threaded. Remove both cups, generously grease the threads or wrap them in plumber's Teflon tape. Install them to the recommended torque which, at 300-350 inch-pounds, is much tighter than you would expect. That should quiet things down.

If you decide to replace the crank and bb, I'd move up the food chain a little and get one with the current HTII. Sora maybe? Much easier to deal with in the future.

Stoopid Dave answer here, but often something as simple as a crank ring bolt will make a creaking sound. The di-electric activity between aluminium and other metals can make the parts rub against each other and create the noises. HTH, MH