I need a Crank Reccomendation. Single Speed, BB30 I am undertaking my first build from a frame. I bought a used Cannondale Synapse Alloy Disc frame. It's quite nice.
I am installing new brakes, cables and everything else. 
Also, I am dead set on using an Internal Gear hub in the rear, and have selected a Shimano Alfine 8. My problem is finding a Single Chain Ring crank that will work with it. The frame says BB30 on it and has a BB30 BB installed. It's got two press fit bearings installed and each bearing has a clip ring on the inside of the bearing. The bike only has a couple of hundred miles on it so the bearings look new.
I cannot seem to find a crank that is compatible with this BB30 setup, and I do not know if I can out a different BB in this frame. My local bike shops are swamped this time of year, so no help for months (I live in upstate NY so we have a short season). I'd appreciate any help or advice!! Thanks, Dave
As mentioned in some comments, many cranks will fit. You need a 30mm width spindle crank. BB30, a cannondale staple crank size, is just this. 

You can use a 24mm crank with an adapter. Some cannondale riders I know have all their bikes set up like this. I don't really like it. Extraneous parts and more weight. The advantages are serviceability and possibly less creaking, though I've never had a problem with this. It's more serviceable because you have a threaded bottom bracket that's easier to remove. (Most home mechanics don't have the proper bearing pusher/pullers to remove and reseat BB30 bearings correctly, though I've seen it done).

Sram is what I use in my cannondale and I'd recommend it. I'm sure BB30 cranks from other manufactures are just as good. The bike came with an FSA crank, but I didn't care for it because it is comparatively heavier and less stiff than my Sram Red BB30 crank. 

Here are some pics of what it looks like in the frame: