Cannondale Bad Boy SS conversion I'm interested in converting my Cannondale Bad Boy 2011 into a single speed bike. I found somebody who's done it on a Bad Boy 2008 (there), and somebody else who's done it one a more recent model (there). 

But a bike expert told me that not every bike can be converted into SS bikes, and that most Cannondale bikes couldn't, because of the shape of the frame making it impossible to put a single speed cog (or something along these lines).

So, I'm looking for advice as to whether I can convert my BB 2011 into a single speed bike, and if so, whether there is anything different I need to do to do so.

Thank you.
I'm guessing that they were talking about replacing the rear cassette with a freewheel. However, you can convert pretty much any bike with a rear cassette to a single speed with single speed conversion kit like this one: 

http://www.universalcycles.com/shopping/product_details.php?id=1764&amp;category=2621

And a chain tensioner like this one:

http://www.universalcycles.com/shopping/product_details.php?id=47140

NB: I don't necessarily recommend either one of those products or the store that I found them on. They're just examples. You can actually even "hack" your own single speed conversion by dismantling a couple of old cassettes and using the spacers in the same way that you use the larger spacers on the ready-made conversion kit.