BMX hubs (110 or 120mm spacing, like track hubs) won't fit in the 135mm spacing of conventional mtbs. On my MTB ss I just used a bunch of cassette spacers on my Shimano Cassette Freehub to get the chainline right and a Shimano DX BMX sprocket. I also run a Bell-branded KMC BMX chain with a half-link. The cranks should work though as will the BMX sprocket.