Hey guys,

I'm building a new bike from scratch and want to use the opportunity to swap parts.
I read here and there, that people swapped their bottom brackets for lighter alternatives, but none is talking concrete models.
So what fits the Brompton frame?

Also, I'm eyeballing a lighter crankset, just not sure if there's an affordable version that's lighter than the bromptons...
I heard, hollowtech is affordable, but how to determine, which bottom bracket fits brompton AND fits with light cranksets?

Quite a complex topic I'm realizing...

Anyone who can open my eyes