i have an aluminum frame crusier,cant get to it right now to measure the bottom bracket diamiter,it was sold as a canvas frame set thatu can build up,they normally have a one piece crank set like old heviweight schwinns,id like to build it into and electric mid motor like a bafang,i think i need an adaptor in the bottom bracket because it was a 1 piece crank set up,any info would be helpful,thank you