Fatboy headset bearings


Well-Known Member
Jun 21, 2018
I have a 2016 Specialized Fatboy. I know that I need a set of bearings, 41mm and 52mm. I'm trying to understand the angles, 36x45. I guess it refers to the angles where the bearings sit in the seats, but what is the 36 angle?

Apparently, Specialized made a number of variations of the bearings, and I can't find specs for the bike which might tell me the part numbers which I need. I've had the bearings out of the bike, but I need to make sure I know what I'm talking about before ordering them.

I wrote to a large bike and parts retailer and it was they who said there are different bearings, and they can't help me with the right information.

What I'm looking at, and thinking these may be the right ones, are here.