My trek Emonda ALR (Alu frame) bottom bracket has noticeably more drag (crank without chain will stop within one revolution of being spun) than my 2012 6 series madone. Any suggestions? I have adjusted the preload (to point where there is none) and it makes no difference. Bearings feel good; smooth with no rough spots.
Weirdly I noticed a lot more drag when I went from the old square taper to HTII external bottom brackets. My old square taper would spin "forever" and the HTII would come to an abrupt halt after only a couple of revolutions.
Apparently this phenomenon has a very infinitely small effect on performance. http://www.bikeradar.com/road/gear/article/friction-facts-measuring-bottom-bracket-drag-39233/
With their measurement being 0.29 Watts to 1.64 Watts - which in the picture of things is nothing.
Your bearings may also be stiffer if they are newer as they do loosen a little over time.
If you have any other concerns - best take to a mechanic to inspect to make sure they have been installed correctly.