The balls are 1/4" hardened steel balls that you can get at your local hardware store. If the races are in decent shape, there is no reason to change them, which are unique to BS. There also is no reason to replace standard ball bearing setup with tapered rollers. For top level racing, maybe there is an advantage, but not for the rest of us. i bought a bag of 100 1/4" hardened stainless steel bearing balls from McMaster-Carr for $13.00 + shipping.