Interesting thread I discovered:

http://forums13.consumerreview.com/crfo ... 8@.efcbeac

What do you think the frame material of the future is? My vote goes to carbon nanotube composites. Pound for Pound, carbon nanotubes are something on the order of 1000 times stronger than our best types of steel. In fact, they are so strong that they are rapidly being developed to be used for a space elevator (!!!!), possibly within the next 15 years.
Theoretically, steel should be a few hundred times stronger than it actually is, based on the theoretical strenght of the atomic bonds between iron atoms. However, its crystal structure isn't perfect, and their are impurities, leading to its comparitevely modest real world strength. Carbon nanotubes are like elongated soccer balls. Picture the grid of a soccer ball extended into a long tube, with a hemisphere on each end. Well, carbon nanotubes are damn near perfect, and thus approach their theoretical maximum strength. Here are some comparisons of straight (not composite) carbon nanotubes to the strongest steels available...

Nanotubes are...
5.7x stiffer
375x stronger
1/3 as dense

1000x stronger...and several times less elastic to boot! Now, these tubes are like strings, so if you are looking for something other than a cable of some sort you'll need to make them into a composite, as we do with fiberglass, carbon fiber, and kevlar today.

Even if the composite is only 1/100th as good as the pure nanotubes, you still can potentially have a frame of equal performance to a steel frame that only ways 1/10th as much! Could you imagine having a frame for a road bike that only weighs 5 ounces!? A complete downhill rig that weighs 14 pounds? How about a 900 pound Suburban?
I can't wait...this'll be a truely revolutionary material!

http://www.applied-nanotech.com/cntproperties.htm

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Thats bad ass! I've heard about this stuff for a while now, but didn't think we were so close to manufacturing capabilities. That would be sick, a 150g frame!!! I'd mess my self. Just imagine how lite all the other components could be, 35g rims, 70g cranks, 10g stems, 5g seat, hell maybe a sub kilo bike! The possibilities are endless. Lets hope they make there way to bikes.

Even if they don't, and it will probley take a long time I think the actual materail of the future for bike is unidirectional carbon fiber. Formerly used in just aerospace industry, but in the last few years it's making it's way to bikes. Lew was the first with its rims, now Reynolds. Campy has the new cranks for 04 made of the stuff to. Not 100% on this, but I think the new Giant TCR0 for 05 will be made of unidirectional carbon fibers giving it a weight of 850g!! With this new technology comming to market expect tons of record breaking lightweight parts that are stronger and more durable then ever.

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A sub one kilo bike: sounds good. But you can imagine that all the bolts will weigh more than your frame

A real light steel frame with steel components 1970 is weighs about 10kg, so you can probably make a 1,5 kg bike. Bar tape, tubulars and glue will be really heavy components.

A roadbike frame with 5 ounces? Maybe its possible to get one in 10 or 15 years. But one little accident and its only dust. For example, take the downtube off the new very stiff Scott C1- frame and press it with one hand, I am sure you can damage it. I´ve tested it and i can press it 1cm with not very much power.
The unidirectional superhighmodular carbon fibers are very inflexibly and brake very fast on a small impact. Cause off that , I think 1pound for a frame is the limit (but I hope Your posts came be true)

Nikh, Nanotube composites are looking toward a great future, but if you want to see the theoretical strength of steel (and Al) approached have a look at some of the steel (or Al) fibers in unidirectional (or woven) form. These are extremely strong, but not as sexy as the carbon variety . When I was working on some composite wheels I was seriously considering using Al fibers in them.

the first place you will see these materials in commercial use would be formula 1 racing, if all works well, we should see it in about 5 years. how hard is it to mass produce, and is anyone using carbon nanotubes now?