Framebuilders - Does Titanium Weaken w/ Age?
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Stupid question for the guys/gals in the know: does titanium weaken with use and age? I am thinking about buying an older (mid-90's) used ti road frameset, but don't know whether or not to 'trust' the bike and therefore am seeking your advice. I am a bigger rider who will be using it for a long day rides in very hilly terrain, and therefore will be putting down some good torque on the bb area etc and don't want it to fail..If it is a quality frameset from a reputable builder should this be a concern or is it 99-100% as strong as it was 15 years ago? Thanks.
11-14-09, 07:32 PM
My understanding is that Ti keeps its strength properties longer than aluminum and even steel.
But maybe some of the Ti builders can shed some light on the matter...
11-15-09, 08:21 AM
I will assume by 'age' you mean 'use' and all that it entails. The short answer is 'yes'.
Likely will not fail all at once. Keep an eye on things (like all bike frames). 15 years is quite a long time, but figuring out 'use' and lifespan is a total guess. Could be creampuff, or could already have cracks. Let the rest of the compenets, etc be your guide.
Ti has come a long ways in 15 years....
11-15-09, 10:06 AM
Titanium alloys, like steel alloys, have a definite fatigue limit (also called endurance limit). Basically, materials with a fatigue limit can experience an infinite number of load cycle stresses below the fatigue limit without failing. For materials that have no fatigue limit (like aluminum and magnesium alloys) every stress, regardless of how miniscule, weakens the material and eventually will lead to failure.
For an excellent introduction to the pros and cons of various bicycle frame materials, read Scot Nicol's series of seven articles Metallurgy for Cyclists (http://spokesmanbicycles.com/articles/metallurgy-for-cyclist-i-the-basics-pg328.htm) (links to each chapter is along the left side of the web page).
Titanium won't weaken with age unless there are repeated stress excursions beyond the fatigue limit of the alloy, which is highly unlikely in normal use. One area where early titanium frames had failures is in the welds at tubing joints. Welding titanium and titanium alloys must be performed with special precautions because these materials are highly reactive to contamination from atmospheric gases; it is important that during the welding process, the area of the weld is shielded from air by performing the welding either in a vacuum or in an enclosure containing an inert gas. Weld failures are now very rare as the frame manufacturers have learned how to prevent contamination.
A well made titanium frame should last a lifetime or longer.
11-15-09, 12:37 PM
They crack like all other materials, it *should* just take longer. Stays, dt's, all the usual places. A friend of mine has a very early Helfrich built atb that has been repaired 12+ times over it's life. It's been ridden incredibly hard 20+ years. Helfrich is pretty much the father of welding Ti in regards to bicycles. There is not a straight across correlation b/t material and frame.. there's a person in between who chooses tubes, welds, etc.
Anything made by Sandvik is excellent.
titanium alloys, like steel alloys, have a definite fatigue limit...etc
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