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What is "untuned" aluminum?(11 posts)

What is "untuned" aluminum?jtolleson
Oct 14, 2001 11:49 AM
I hear this phrase describing, especially, lower and mid-range production al bikes, but I don't know what it means.
My guess is strait gauge, round tubing that isn't taylored for..Tig
Oct 14, 2001 1:49 PM
...specific loads, stiffness, and rider comfort. That's what you see on lower range bikes. I could be wrong though.
I see a marketing termjacques
Oct 14, 2001 2:19 PM
My guess is that "untuned" aluminum is a marketing term. Aluminum alloys, such as Al 6061, are used in the manufacture of fishing boats, step ladders and bicycle frames. Recently, a large U.S. bicycle manufacturer started advertising bicycle frames made from a proprietary aluminum alloy the company says was created especially for making these frames.

It's possible that someone introduced the term "tuned" to set this "bicycle alloy" apart from the old standby 6061.

Of course, HOW the frame is designed and built is much more important than WHAT it is made out of. But marketing forces being what they are, material has a magic all its own.
re: What is "untuned" aluminum?cycleguy
Oct 14, 2001 4:58 PM
When you crash it resonates off key?
THAT's where my brain was headed... ; )jtolleson
Oct 15, 2001 6:40 AM
re: What is "untuned" aluminum?dsc
Oct 14, 2001 5:30 PM
I believe it has to do with the shaping and butting of the tubes, that in turn give a bike a particular type of ride quality. This, of course, will cost more.
just a guessweswu
Oct 14, 2001 5:36 PM
As one of the above posts says, it's all about design of the bike. This includes how the tubes are designed. As those who owned Cannondales 10 years ago can tell you, aluminum back then was light, stiff (unless you bought a Vitus) and broke your back if you rode it more than 15 miles. Modern aluminum bikes are equally light, stiff, but are much more comfortable.

The idea is to create butted tubing that maintains torsional stiffness, but gives in the right places so you don't get jarred by every little bump. This just means using butting differently - not just figuring out how thick the walls should be, but where the butting should be too.
re: What is "untuned" aluminum?tr
Oct 14, 2001 6:07 PM
In the engineering world, tuned and untuned relates specifically to whether or not one has designed the struture with or without specific knowledge of the natural frequencies of the structure. Ride quality is usually low frequency dependent, whereas stability (in a decent design) is more high frequency dependent. Like wheel shimmy, this is high frequency. An untuned aluminum bike frame to me would be a frame that was built without knowledge of the low and high frequency characteristics of the frame. People like to equate ride quality with stiffness, but it is not that simple. Equating it to stiffness only is neglecting the mass. Ride quality (in general)is somewhat low frequency dependent.
contextzzz
Oct 14, 2001 6:29 PM
What was the specific context you heard the words used in?
contextjtolleson
Oct 15, 2001 6:42 AM
I've heard it when people are evaluating (usually not positively) some entry level Al frames like the Trek 1000, Canny R300, whatever. One of those critiques that makes newbies afraid to spend less than a grand on their first bike.
From a bike builder:cyclequip
Oct 15, 2001 4:46 AM
Firstly it has nothing to do with butting. That is a mechanism used to lighten tubes without interfering with weld-joint strength.Butting also has very little to do with ride quality overall.
Tuning can only refer to the absence of artificial ageing or heat-treatment of a finished bike. This is the biggest differentiator between cheap and less cheap bikes.