so i finally got my 09 rush hour. it comes with a 46x16 combo and i wanted to swap out the 16 for a 18 freewheel. Without knowing the current chainring/cog setup is a 1/8", i went ahead and bought a 18t 3/32" freewheel cog to replace. Can i still use it?

http://farm4.static.flickr.com/3219/...0a2ea728_b.jpg