RC try link above or goto analyticcycling.com and try some #'s,I think you'll find that the gains from weight savings are pretty freakin minimal,aero makes a bigger difference per $$/spent than any other improvement.More evidence can be pretty instinctive....example recumbents,streamliners>hpv's etc....some of those things are quite heavy,but for flatland speed aero is everything.Just like many think the switch from mtb to roadie is a huge automatic speed gain,it isnt........both can be set up pretty closely and you'll find the diff in rolling resistance@20mph tween a mtb and roadie is only about 15watts,barely noticable.(assuming good slicks and similar riding position) I ride a couple bikes that as bout as different as they can be weight wise,one is about 32lbs,other is around 16.5lbs,similar gearing and riding positions.....yes I can feel a difference tween the two,it might save me 5mins in a 30mile alleycat race,or save me some calories I need to eat after a workshift,but the difference isnt enough to worry about.Unless your climbing most of the time,and steep stuff...>8% or more being a weight weenie just doesnt pay well.Its easier to get more aero and or/add more power.Much more effective too....why obsess over grams when with some work you can increase your power output by 50% or more?