I get the avid bearings with the yellow shield on one side and metal on the other. Put the metal shielded side to the inside of the hubs and diff holders. But avid bearings are great. Mine last 4-5 race days before the hub bearings get gritty. Pull the teflon (yellow) shielded side blast with some motor cleaner from metal shielded side, or put some motor cleaner in a small container with a few bearings, shake for about 30 seconds and good as new. Never had a problem with the larger diff carrier bearings.