I recently had my bike (Focus Mares CX) serviced by my LBS, during which they replaced my wheels with a set of new Campagnolo Khamsin wheels. In the month since I had that done I've found it markedly harder to pedal; I'm suddenly struggling to get up hills on my commute that were fine before, despite also having switched from a 27t to a 28t largest sprocket, and I'm drifting back from my companions when we're freewheeling.
When I remove the wheels and hand-turn the axles, the front one rotates smoothly and freely, whereas the rear one rotates smoothly but viscously. There's a lot more resistance than I'd expect, and compared to my friends' bikes. In the past I've always had cup and cone hubs, so this sort of problem was usually down to an overly tight cone, but these hubs have cartridge bearings and I'm unfamiliar with them.
I'm finding the hub schematic (pdf) a bit difficult to get my head around. There's an endcap on the non-drive side that's secured with a pinch bolt, which is apparently used to take us slack if there's play in the axle, but loosening it has no effect. Is there another bolt that I could loosen? The new wheel sits much tighter in the frame than I'm used to, and I wonder could the LBS have tightened up something so much to get it in the frame that it's overloading the bearings?