Jan 7, 2003 10:02 PM
|I've heard, can't remember where, that Scandium frames have a finite life. Are we talking fatigue life as in so much stressing or calendar life as in so much time?|
|re: Scandium||The Human G-Nome|
Jan 8, 2003 4:26 PM
|scandium is just an ingredient in a few select frame tubes that make up less then 1% of an alloy's composition. zinc, mangnesium and the like may also be in play. the scandium itself has nothing to do with "fatigue life", but will have something to do with the overall strength and stiffness of the frame. thickness, diameter, geometry and design have everything to do with the actual "shelf life" of any aluminum frame.
currently, Easton makes the most widely known tubes which employ scandium, the Easton Scandium 7000. many people, including internet sources, magazine articles and even your local LBS will tell you that Deda's SC61.10 has scandium. it does not (not even in trace amounts). Deda's U2 does have scandium, however. it's shelf life will be limited specifically due to the thinness of the tubes, although that is mostly in theory since they haven't been in play for very many years. 61.10 however, to this point, has proven itself to be very durable.
some folks say frames made with scandium "ride more like steel". i guess that's for you to decide.
Jan 10, 2003 6:54 AM
So is SC 61.10 just good aluminium? What's it exactly please? Just curious about my Pinarello tubing. Thanks
|re: Scandium||The Human G-Nome|
Jan 10, 2003 2:55 PM
|it has trace amounts of zinc and magnesium and has compared favorably to tubing that utilizes scandium. if i wasn't at work, i'd point you in the direction of some sites that break down the composition, strength and fatigue.|
|source of scandium myths||Kerry|
Jan 8, 2003 5:08 PM
|As noted by another poster, scandium is an alloying element in aluminum. It does give the Al very slightly higher strength so it can be made very slightly thinner (and lighter) and still resist the "beer can" effect of easily dented tubes. However, with the introduction of Sc alloys, builders went much thinner than the actual metallurgical improvement would merit, and so many Sc alloyed frames are quite light and quite fragile. It is not the fault of the Sc alloys, it is the fault of design. Any Al frame has a finite life due to fatigue, not due to sitting in the closet. However, there is no way to predict that life in use due to all sorts of factors like rider weight, riding style, road conditions, accidents, etc.|
Jan 9, 2003 1:02 PM
|My only experiences with Easton Scandium were two Rocky Mountain Turbo SC road frames, and each broke at roughly 3500 km of riding. It should be noted that both broke at the junction of the right chainstay and chainstay bridge, and the tubing used for the stays was Easton Ultralite, not SC7000.
The Rocky Turbo frames were notorious for breaking at this junction, and Rocky sold their remaining stock to Colorado Cyclist who re-badged them as the Douglas Stealth. If anyone has bought a Stealth, please keep an eye on the drive-side chainstay where the chainstay bridge is welded on. The crack will appear on the chainstay just to the front of the weld.
In terms of the Scandium tubing.....I'm sure if built properly it will have about the same fatigue life as any other high-end aluminum frame. I did like the ride of the Rocky SC, it seemed to transmit a little less road vibration than the regular Easton Ultralite Rocky frame. Probably the smaller diameter tubes of SC7000 were responsible for this.
Jan 15, 2003 1:58 AM
|Here's a link to the definitive article on the technical properties of scandium and the myths;
Here's a link to an article (in german) comparing the test results of scandium to other aluminum alloy frames;
Note: You can use www.freetranslation.com to view the website in english!