At 8:55 AM -0800 1/21/08, Tom Dalton wrote:
>Jan wrote:
>
>So that brings up the question of when aluminum bikes and parts
>became reliable. By the mid-1930s, they certainly were almost totally
>reliable. Aluminum frames still had a higher failure rate than steel,
>but probably not much higher than many modern materials.
>
>Jan,
>
>You're the last person I'd expect to possibly spread misinformation
>without some solid facts for backup. Which modern frame materials
>are you suggesting would have failure rates comparable to 1930s
>aluminum bike frames? Ti, CF, Al? While you say "many" modern
>materials (there really are only 4, generally speaking) I would have
>to assume that you're talking about CF, because Ti, for all it's
>shortcomings, is generally accepted as pretty durable, and to
>characterize modern Al as only slightly more reliable than Al bikes
>from 7 decades ago... well, that seems like a huge reach. Then
>again, I trust you have some solid data to add.
>
>My uneducated guess is that if 1930's AL frames were not failing at
>extremely high rates, it was because they were not being used.
>
>Tom Dalton
>Bethlehem, PA, USA
Failure rates are hard to quantify, because, as you say, they make sense only when related to the mileage ridden. And those numbers are not available. So I am sorry if you consider any talk about failure rates misinformation.
I was basing my observation on anecdotal evidence, and I was mostly talking about carbon fiber. I know a bike shop that has a nice collection of failed carbon seatposts, failed carbon forks and more. I talked to another shop who told me the number of broken aluminum frames he has sent back to a major American maker under warranty, and that number was impressive, too. After years of titanium alloy bottom bracket spindles failing, the material now appears to be used only in more suitable applications. What is the fourth modern material you mentioned?
In the 1930s, there were two important makers of aluminum frames in France: Caminargent and Barra. Caminargent frames were bolted together, and tube replacement was easy. I have not heard of failures, but none of the riders I have interviewed liked the ride. They said it was too flexible. Barra brazed his frames from aluminum, and there were some failures, usually early in the frame's life. Several Barra frames were ridden in the Tour de France in the 1940s. Many riders liked them a lot, and they rode them hard. Yet a lot of these frames have survived intact. So the failure rates were higher than good steel frames, but not so high that nobody bought them, or that the maker went out of business. (Barra made thousands of aluminum frames over a 20-year period.)
My initial point was that many 1930s aluminum alloy parts appear to have been reliable - not 100% (but what is?), but reliable enough to find widespread acceptance. The 1930s also appear to have been the time when aluminum alloys first saw widespread use in high-end bicycles.
Jan Heine
Editor
Bicycle Quarterly
140 Lakeside Ave #C
Seattle WA 98122
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