Hi,
I read this a couple of minutes ago and thought it would be a fun read
http://www.bbc.co.uk/news/health-11958903
My opinion is that a weight difference of 1 kg or 2 will not change my commuting times by much. My commute is only 30km each way so I might get to work 2 or 3 minutes earlier in the lighter bike. I only have 3 traffic lights to contend with to get to work but I reckon getting caught at the lights will impact my commuting times a bit more.
J
