Originally Posted by
Tourist in MSN
Even with a cross chained drive train on the larger sprockets, the friction losses in watts were not much higher than with the sprockets that had a better chain line.
Cross chained will be less efficient than straight, no matter what the gears used are. But those articles do make very clear that gear selection (i.e. an 80x40 would be more efficient compared to a 20x10 due to the less articulation angle/bend) effects the efficiency.
The stakes are high is this Everesting business
and I'm sure future challengers will chase every marginal gain they can get. The oversized idler on Ronan's bike ranges $500-1500 based on options, and eventually people will run out of things to buy.
Another place to look for info on going fast with the least effort is the IHPVA (International Human Powered Vehicle Associations, ihpva.org) journals -- lots of scholarly articles (though dated) if you're trying to build bikes that people can beat the existing speed record of 89.59mph (or just pedal over 60mph+).