Some race balls had flat areas that resulted in frictional and torsional bindings. I found several SKF bearings of the same type that were just great. SKF is a true bearing manufacturer.
FKG 99502HNR Bearing Width Pre Lubricated
5 Review
Enhanced Performance Sydien SCS12UU Bearing Bushing Diameter for Precision Machinery
4 Review
Linear Clamping Support Bearing by Sydien
4 Review
π Wheels Manufacturing Ball Retainer Bag: Convenient Storage and Protection for Your Ball Retainers
6 Review