I have a 2008 Specialized P2 and want to convert it to a single speed. I've checked for kits, but the ones I find on PricePoint etc. are all for cross-country single speed conversions. I want to run a BMX drivetrain and want to put a BMX cog on the back. The one that Specialized uses on the P1 is a 1/2" x 3/32" x 16t with a Shimano spline and conversions spacers. However, I can't find measurements on the BMX cogs. Has anyone done this or a similar conversion?