What bottom bracket fits a Truvativ E450 crank?
It's just an older style of BB. It's a square taper BB. Simply remove it and it should indicate width of the axle and the cup size (very likely 68mm). Then go order a Shimano BB-UN52 for less than $20 online. It'll outlast the rest of the bike. BTW, you can still find these cranksets on ebay. Good luck!