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So if the new steel has a greater specific strength whilst retaining similar Young's modulus (stiffness) to cromo or other common bicycle steels, we could get stiffer or lighter frames (or both, if oversized), and potentially cheaper than Ti.
How oversized do you want to go? Reynolds already make a 34.9mm 953 tube with walls just 0.4mm thick. If you push too far in that direction (ratio of diameter to wall thickness), you get something which has to be handled with care to avoid dents.
"Cheaper than Ti" is setting a pretty low bar, and if money is the problem then both aluminium and carbon fibre already easily win.
if someone invents a steel with a greater yield strength, our chains could be thinner and lighter for the same performance characteristics
I'm not sure that yield strength is the limiting factor for chains even after you have accepted faster wear from thinning the components. At some point, elastic extension under load will make the rollers start to ride further up the tooth flank, and the loss of efficiency will probably outweigh any gains from having the chain a few grams lighter. A chain which is 2% longer thanks to elastic deformation should be as inefficient as one which is 2% longer thanks to worn pin holes, I think :-)
On 39/23 gearing at 500W input and 80rpm, chain tension is about 750N. Not sure how strong road chains are, but if they are only half as strong as track chains then 5000N should be the minimum breaking load. Using some quick and dirty assumptions, we're probably running our chains at no more than 0.5% elastic elongation. If your miracle steel allowed you to halve the thickness of the plates, you'd save no more than 100g and you'd be running at up to 1% elastic elongation. That doesn't seem like much of a bargain to me.
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gbj_tester
^ this is all conjecture since none of us knows any of the specific properties of the new steel, but the Nature paper mentions improvements to the specific strength (i.e. the yield-strength to weight ratio) of the material, which is important.
As a material, aluminium is significantly less stiff than steel. But its specific strength is far greater. This means you can build a thicker-walled aluminium tube at the same weight as a normal thin-walled steel tube. The result is a stiffer tube - and if you oversize the tube, taking advantage of the thicker wall, you can have a tube that's both lighter and stiffer.
So if the new steel has a greater specific strength whilst retaining similar Young's modulus (stiffness) to cromo or other common bicycle steels, we could get stiffer or lighter frames (or both, if oversized), and potentially cheaper than Ti.
Not to take umbrage at your comment regarding limiting factors, but it depends entirely on what you mean by strength (yield, ultimate, tensile, compression, fracture, creep? The list goes on!), and also what you mean by 'limiting factor' in the first place (stiffness, weight, durability?). For example if someone invents a steel with a greater yield strength, our chains could be thinner and lighter for the same performance characteristics, but consequently could be less durable - so which is the limiting factor, weight or durability?