My touring bike currently has FSA Megaexo BB-4000 bottom bracket with FSA Omega CK-4000a tripple-ring 9-speed crank set (can't find the product link on the FSA web site).

I would like to know what my options for replacing the BB are. It seems to me that the BB-4000 is not very well regarded and is expensive for what it is. From what I'm reading, Shimano HT2 brackets seem to be in the sweet spot for the price/quality ratio, as well as being more ubiquitous (a plus for touring).

Is there any way to upgrade to a HT2 BB and keep the current crankset? It seems wasteful to replace the crank, there is nothing wrong with it and the chainrings are fairly new. I'm hoping there is some kind of an adapter to use the Omega crank with a HT2 bracket.

If I have to replace the crankset, could you tell me whether a 10-speed crankset will work with a 9-speed chain and front derailleur?

Any product recommendations are welcome. I am mostly concerned with reliability and replaceability, less with weight.

A Megaexo crankset will work with a Shimano BB fine.

For reliable touring I would go with this crank and a shimano BB. Sugino XD2 Crank, Triple 46x36x24

"Upgrading" your FSA bottom bracket to one of the Shimano HTII sets is a low cost change but if the crank and chainrings themselves are OK, there is no benefit to paying for a different one.

Thanks for replies, everyone.

I'm going to get a BB-5700 bottom bracket and see how it works out.

I did some more research, and I found in a couple of places that the BB-4000 bottom bracket is for spindle diameter 19mm. For example see in the item description here or see in the picture (hover over the top of the BB) here. I understand that Shimano Hollowtech II brackets are designed for spindle diameter 24mm.

Is the info I found correct? If so, then why some of you are confident that the MegaExo cranks are compatible with HTII bottom brackets? Or is MegaExo not a standard name, and some MegaExo brackets are for 24mm spindles?

Is the BB-4000 bottom bracket my only option for use with this crankset?

Many thanks!

Ah, I had forgotten about those damn "MegaExo 19" things.

FSA MegaExo - diameter 19 - FSA

Yeah, Shimano BB won't work if your spindle is 19mm. I've only ever dealt with FSA MegaExo cranks with the 24mm spindles.

I didn't forget about them, I never realized they existed in the first place. Yes, your only way to use a Shimano HTII bottom bracket would require replacing your crank also. For a triple I recommend a Shimano FC-5703 which still uses a separate 74 mm bcd granny ring giving you a lot more choices than the 30T OEM granny. Yes, it will work with a 9-speed chain.