I need to replace my headset bearings but i dont know what to order. The numbers are: Upper - 3f27 6b 7hx41.8x30.2x45x45 lower - 3c26 15? 8hx52x40x45x45
41.8 is the innner size. You have a bigger diameter steerer on the lower bearing. the 45 deg is the race angles. There are plenty of places on ebay that sell reasonable bearings for buttons. Just remember to prise out the seal and pack with grease before fitting.