FS: (Trade) My new Sugino Zen 47t for a 48t

I purchased a 47t because it gives the most skid patches with just about every rear cog. I then found out my local velodrome is going to only 48t this next season.

My chainring has less than 500 miles on it...practically brand new.

The 48t must be black and in decent condition.
You can see mine here...
http://www.pedalroom.com/bike/bianchi-p...

Thanks