I use standard bearings, pull the inside seal out and flush them with brake cleaner. Install them in the bird cages with the outside seal still on to keep the oils in and dirt out but leave the inside seals out. I also drill a small hole in the top of the bird cage for the plastic straw on the spray can to lube them before each race with slick50 with Teflon. Most people use triflow but any good lubricant will work, slick50 has Teflon, works great and is half the price as triflow.
My axles spin very freely without the high cost of ceramic bearings or the high dollar ones. They had some on display at the dirt grand’s and mine actually seemed much free’er.
You can contact Mark Baumann at 614-224-4291 or visit their site at http://www.bdi-usa.com/
for bearings EBC R20 ZZ