Originally Posted by
gregf83
I think you've got it backwards here. Changing from an upright position to an aero position with close to a flat back will make a very large difference. It's not hard to see a 10% improvement in speed which would take an extra 30% in power. Adding 30% to your power is difficult for someone who has been riding for a while although feasible for a newer rider. In any case if you want extra speed, changing your position is low cost and relatively easy.
It will make a difference, but at 15-16mph, it's not huge.