Have folks been following the discussion on the framebuilders list (at bikelist.org)? Boy it is heating up. Seems like a certain framebuilder from Connecticut (Not the one who builds wonderful rando and brevet bikes) is having a fit over the claim that the choice of frame tubing can make a discernable impact on the ride of a bike. Seems like that builder and some others are having difficulties admitting that sometimes, and for some riders, more flexible frames are the better widget.
In fact, the very idea that tube diameter and tube gauge can affect the way a bicycle rides is being challenged! This is rubbish!
During my college days, when I was known to watch metal melt and make a few frames, I was firmly in the camp of stiffer is better. I remember going to the NY bike show and I puchased some Ishiwata tubes that featured chainstays that flared out after exiting the bb shell. Boy were the frames I built with this tubing stiff! For a crit bike, I suppose it was at least entertaining, and at the time I loved it. Those chainstays really did make a difference!
But I kept riding bikes such as Colnago Supers, that were just built from regular Columbus SL. I kept wondering why those bikes were not as stiff, yet they rode wonderfully and seemed so fast.
Fast forward to when I owned Bicycle Classics Inc. around 2001 and 2002. We were selling Waterford bikes, and for some reason the standard Waterford 2200 wasn't completely firing me up in my size. So we ordered one with a heavier downtube. Well we only went up by a smidge, and just on one tube, and frankly I couldn't feel the difference. But then we ordered yet another one (all these had the same geometry), and this time specified heavier downtube AND heavier chainstays. And boy was that bike different! I'm not sure it was different in a good way, but the change in feel was immediate. It felt stiffer, but also less alive and went thud more it seemed over the bumps. The bike lost a bit of its balance. Other riders didn't mind it, though, but I don't recall anyone who rode it and the stock example who couldn't tell the difference.
I think, perhaps, we had to be the only bike shop that had identical bikes with different tube sets on hand for riders to experience!
And interestingly, we also sold the 531 version of Waterfords 853 bike, and that bike had much heavier tubing in the sizes I was familar with. And gosh did those bikes ride different. For folks who wanted stiff, the less expensive thick-walled 531 bike was a radically different ride than its siblings in thinner walled 853.
Why did we go through this effort comparing bikes and tubing? Because riders have different prefferences. Some riders like stiff, while others like flexy. Now some riders also are sensitive to the differences and really care which they ride. Other riders can tell the difference, but are able to tweak their riding style to get in sync with most any bike. I'm in the later category, but up to a limit.
So to say that tubing choice doesn't matter is absurd in my opionion. It may not matter to a particluar rider, but it matters greatly so a great number of riders.
Now many riders have come to realize that the light gauge tube sets with lots of flex work wonderfully with their pedaling style. This is not true for everyone. But nobody is saying that flexy is good for everyone. What is being said is that folks need to find the right flex for their riding style and preferences.
At Rene Herse Bicycles / Boulder Bicycle we spend lots of time learning what works for us, and how that translates to making bikes that are enjoyable for our customers. It is a royal pain, we would save lots of prototype dollars if we didn't do it. But we have to do it. And most of the top builders we know do it as well.