What size is the upper bearing on a 2013 Trek Speed Concept 7.0? I'm looking to replace the upper head bearing in my 2013 Trek Speed Concept 7.0 but cannot find the item online. Any ideas of a FSA/Canecreek bearing to replace it? 

Just to clarify, the diagram below shows the 2014 service manual that depicts an upper head bearing of W276442. I don't know if that's the same for the 2013.
I got the answer from Carl an Engineer at Trek. Turns out it is:

http://forum.slowtwitch.com/gforum.cgi?post=6040711#p6040711


  that's the upper headset bearing PN for all SCs, 2010-present, with the external steerer (aka bayonet style) fork. it's a custom
  bearing, so I'm not sure you'll find it anywhere other than through
  your Trek dealer. 
  
  1st generation SC 7-series bikes (which technically were model years 2010-2013) that had a standard stem on a 1" aluminum fork
  steerer used a 1" cane creek upper bearing, PN 428420 from your Trek
  dealer.


I wanted to buy it online so I found it by the Cane Creek model #

http://forum.slowtwitch.com/forum/?post=4773430#p4773430


  The original SC7 upper headset bearing is a standard 1" threadless
  headset bearing with 45deg chamfers...your Trek dealer can order PN
  428420...Cane Creek PN is BAA0004K.


Ordered part BAA0004K from Amazon. That should do the trick.