Originally posted by rod_b
I don't know what the exact difference is but you can easily tell just by holding both in your hands.
Has anyone tried the 22T front pulley and if so, how much split did you run between the front and rear tires?
The front internal ratio with the 23T side pulley is 2.42105 (pretty sure! don't have the car here) and the 22T side pulley is 2.31578. This works out to be a 4.5% overdrive situation.
It seems that the split should be around 3mm like D said to keep a 1:1 front/rear ratio.