actually, my dad did something, hes a machinist, and he like shaved a little bit out of my bearing slots and they are like amazing now. so much faster. but if i were you, buy them with the bearings in them. And also, if you take them out what you do is use a little like center punch and tap them out in like a square pattern and they pop right out. I tried to take one out how i normally do it and it took like half an hour and my dad did the other wheel in a matter of 5 minutes. so, just do it right.