|Next frame material???||Brian N|
May 14, 2001 9:10 PM
|Hey guys, |
I was reading the post about the metal matrix tubing and that got me thinking: what do you think the next big breakthrough material is going to be for bike frames? It seems aluminum is the big push right now, with the scandium alloys. My bet is aluminum-lithium alloys. Since lithium is exceedingly light (atomic #3 as compared to aluminum's #13, silicon's #14, and scandium's #21), the more you add, the lighter your bike is! I forget what the range of lithium additions are in these alloys, but the alloys are exceedingly light. I think they're only used in aerospace/military applications right now, but give a few more years of military cutbacks and we all know where that technology gets dumped! Any more ideas? I'm still a steel man through and through... (still hoping Carpenter decides to make aermet 100 in bike tubing sizes!)
|Info on Reynolds and Dedaccai Al-Li alloys||The Kid|
May 14, 2001 10:40 PM
|Reynolds X-100 series is an aluminum alloy with lithium and copper as the primary alloying elements. As far as mechanical properties go, Reynolds' web site lists fatigue life over 100% better than 6061-T6, strength 50-100% more than 6061-T6. They predictably claim that frames made from this alloy can possess the light weight and stiffness of modern aluminum frames with the ride quality and longevity of steel.
The post-welding heat-treatment process is long (measured in weeks, not hours), expensive and exacting. In the recent past, Reynolds UK has let some local builders make a few frames and then send them to do the heat treatment in Reynolds' labs. As far as I know, there are no production frames being made with this tubing yet.
Interestingly, Reynolds claims that adding lithium to aluminum increases both it's strength and stiffness. This would run in the face of the conventional wisdom about different alloys of the same basic material - you can generally increase the strength of an alloy by changing the alloying elements or heat-treating or cold working, but very rarely can you change the stiffness (Young's modulus) of the material.
I have only seen one frame in this tubing in person. It was on display at the Reynolds booth at the Interbike show last year, and made by a custom builder in England. Without paint, a 56cm frame weighed about 2.2 pounds, with tubing diameters significantly smaller than one would usually expect on an aluminum alloy frame. As it was not built into a bike, I can't vouch for any ride qualities.
I have also heard rumors about a second "X" series alloy from Reynolds - X-200, an Aluminum/Beryllium/Copper alloy. Don't know much about it, though.
Reynolds, even in its new, post management buy out organization, is a very conservative, very traditional and utterly British entity. It may be years before we see these "X" alloys widely used.
Dedaccai, on the other hand, seems completely willing and able to introduce and support a dizzying variety of new frame materials and tubesets each year. This past year at the Milan show, the brothers Pegoretti showed their CCKMP frame, built with a Dedaccai U2 tubeset, apparently a new aluminum/lithium alloy. Again, the magic words are "weight of aluminum, ride of steel." Hard to find more details on that tubeset or alloy, though. Gita imports the frame into the US, though, at $2000 for a frame and carbon fork.
May 15, 2001 4:43 AM
|Magnesium + Lithium||Sky|
May 15, 2001 7:30 AM
May 15, 2001 8:49 AM
|its super strong and could be grown to the shape of a complete frame maybe once you play with the genes...maybe not|
May 15, 2001 8:56 AM
...the last in a series of articles about Bicycle frame materials.
The article discusses thermoplastic composites, aluminum metal matrix, as well as magnesium.