I was hoping I could track down what I had read not long ago on some very
interesting thin-wall aluminum bikes that were produced in, I believe, the
1980s. With aluminum lugged construction if I'm recalling correctly.
Apparently they rode wonderfully and are nothing like the big-box aluminum
bikes we're used to today.
Steel is three times as stiff as aluminum, all else equal. So you'd think
aluminum frames would be less stiff! Except, because its also lower
strength and doesn't have the fatigue resistance of steel, tubing is made
larger and thicker which more than offsets this. The aluminum frames can
still be lighter because the yield strength to weight ratio is better with
aluminum, and by using larger diameter tubing, stresses can be kept low
enough to not have fatigue issues (for the expected frame lifespan ...
eventually, their time will come, which isn't necessarily the case for
steel). The reason you don't see aluminum frames with a nice flex to them
like well-made steel frames, is because if aluminum is allowed to flex to
that extent it will fatigue quickly and end up failing. Under a certain
level of stress, steel won't fatigue, but aluminum still will, no matter
the stress. So with aluminum you've got to keep the stresses low enough the
fatigue life is longer than anyone's likely to ride the bike.
Aluminum is really popular these days because you can thicken up that frame
quite a bit, protecting the manufacturer from warranty claims for dented or
cracked frames, without it getting super heavy. The lack of rust is a big
plus in the casual cyclist's eyes, and the ease at which the tubing can be
formed to all kinds of shapes (via hydroforming, among other processes)
makes designing elaborate cargo bikes and the like a lot easier. The rough
ride tends to be solved by wider tires these days; suspension being the
next line of defence. I reckon it's more attractive for the manufacturer to
sell you suspension, which they can up-charge for... and also, as little
sense as it makes to all of us, steel is seen as 'outdated' compared to
aluminum for bicycle frames. It's dead wrong but .. well, so are a lot of
the general public's notions about things.
On Friday, 11 August 2023 at 04:13:44 UTC-7 alan lavine wrote:
> Appreciate your thoughts, everyone.
>
> On Friday, August 11, 2023 at 12:48:17 AM UTC-4 Will M wrote:
>
>> Alan, Jan Heine's 2021 book, *All Road Bicycle Revolution*, has some
>> good reading on this topic ("characteristics of a great frame can be
>> obtained from all materials"; p. 174) that aligns with Sheldon Brown's
>> writing from 20 years ago
>> <https://www.sheldonbrown.com/frame-materials.html> ("the reality is
>> that you can make a good bike frame out of any of these metals, with any
>> desired riding qualities, by selecting appropriate tubing diameters, wall
>> thicknesses and frame geometry"). They both argue that the "feel" of a
>> frame is influenced more by frame design than by the material itself.
>>
>> This doesn't answer your question. :-)
>>
>> I'm not sure I have an answer. All I know is that my aluminum Yuba Sweet
>> Curry cargo bike is the stiffest thing on the planet (to give 300-lb cargo
>> capacity; look at all the aluminum trusses
>> <https://www.flickr.com/photos/millhiser/52222090285/in/album-72157718795961798/>
>> !).
>>
>> And that I agree with Matthias: my "forever bike" is also a C'dale
>> adventure touring bike (this T1000
>> <https://www.flickr.com/photos/millhiser/52412267528>; the aluminum
>> CAAD2 touring frame) that turns 25 in December. I had posted previously
>> <https://groups.google.com/u/1/g/rbw-owners-bunch/c/D-pKAbwxr4U/m/9hf6sGA0AgAJ>
>>
>> about how I am slowly turning it into an Atlantis, having drunk too much
>> Kool-Aid in Walnut Creek. But I must say that the T1000 rides better than
>> any RBW bike that I've owned. Blasphemy, but there it is. Something about
>> its chromoly fork's geometry gives it magical handling. If only it had the
>> Atlantis's clearances. I am waiting for the aluminum to fail so I can get
>> in line for the next Atlantis batch. :-)
>>
>> Will M
>> NYC
>>
>>
>> On Sunday, August 6, 2023 at 5:32:56 PM UTC-4 Nick Payne wrote:
>>
>>> As I said in another thread (
>>> https://groups.google.com/g/rbw-owners-bunch/c/tAas6urcOwg/m/KW63fr0LCQAJ),
>>> modern aluminium frames can be quite comfortable. Last week I did back to
>>> back rides on successive days over the same chipseal roads on that Al bike
>>> and on my Riv custom. I can't say that the Riv felt any more comfortable or
>>> better handling. The Al frame was running Conti GP Urbans and the Riv Rene
>>> Herse Bon Jon Pass, both nominally 35mm tyres.
>>>
>>> Nick Payne
>>>
>>
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