My son has a track bike he loves. We do light tours on it, but the 'no gear thing' is getting him down. Anyone know where I can buy a rear wheel laced with a SA or SRAM internal geared hub for the bike that is ready to go, as in put the tire on and mount it? We'd like a 3 or 5 speed. He does not run fixed, but rather single speed now. We'd have to buy online, live remotely.