NickOnABike There is a lot of science to going fast on a bicycle. Jan Heine of the Bicycle Quarterly has published quite a few blind studies he funded that debunked a bunch of cycling go fast myths. Go to his website and cycle through his stuff. He is the guy that started the move away from ultra narrow road tires by the pro cyclists. I haven't read his latest but he was into some pretty good size tires on racing bikes he had built for his tests and they were going as fast or faster than narrow tired bicycles. As a big person myself at 6ft5in. I did my share of on road bicycle racing in the 1970's and the one takeaway from that experience is that smaller men can be just as strong as big men with a much lower aerodynamic presence. The power to shove our big bodies through the air is quite a bit more than a smaller person so it is much harder to be a successful bicycle racer at our size on diamond frame style bicycles. Of course you could try recumbent bicycles which by their design place the rider in a much more aerodynamic position and gets rid of a lot of that drag. No amount of aero engineering on an upright diamond style frame can make them as slippery as a recumbent. But recumbents are not allowed into diamond style races under international rules the french came up with in the 1930's against recumbents. After reading Jan Heine's studies I think you will have a better notion as to what material and style of frame you might be looking for. The advice from all the respondents so far is very good and is also a good starting point in your search for a racing bicycle. I ride a 67cm 1980 27x1 1/4" steel bicycle that is one of the fastest I've ever ridden. You can find fast a lot of different ways.