OK what do you think contributes to good "feel" of a bike frame, with regard to high frequency vibration, then?

I mean what frequency would you class as road buzz? With that we could start to analyse what's going on.

When I look at the damping ratio of steel[1] I see something around 0.01 - 0.05 which is under-damped.

Carbon fibre can be somewhat better at between around 0.1-0.3 i.e. an order of magnitude better but still not what I'd consider a shock absorber.

I'd be surprised if much high frequency vibration that's made it through the tyres is actually damped by the frame.

With regard to non-blind, anecdotal comparisons I own and regularly ride bikes made from steel, aluminium and carbon fibre. I'm in the camp that thinks a long flexible seat post will do much more for comfort than frame material.

If you know of a study showing otherwise though, I'd be really interested to see it.

1. Sorry I can't find exact figures for 4140 CroMo but I don't think it's outside of this range.

It was a long time ago that I compared bikes, but I remember really feeling the texture of all the little pebbles that makes up road pavement on a carbon fiber bike. Then with an old steel bike, it felt as if the road had been polished into smooth glass surface. This difference was especially noticeable in the feet.

At the time, I assumed the difference was the frame material, but I really do not know the cause. I do believe there is something that could be quantified as opposed to just a psychological effect, but it could be something non-obvious like the typical curved shape of old steel forks; or the frame geometry or tube diameters; or even something else that just correlates with frame material like the tendency of old steel frames to have hand-built wheels with lots of spokes as opposed to the newer (seemingly) rigid factory wheels with fewer spokes.

Your anecdote is exactly the same as all others claiming to be able to tell the difference - there's not enough information in it for anyone to be able to make a judgement either way.

I would expect that a person conscientious enough to know how shocks, wheel size, tyre type and pressure, saddle type, and speed affect ride comfort would also include that information in their post.

Therefore, these anecdotes amount to "I rode on two different bikes which happened to have different frame materials and I could tell a difference in the amount of vibration." Meaningless, even if we don't consider human biases, after all these aren't blind tests.

I would be curious to know if there is a difference that can be felt, but in the end it's of no practical use. I bet even slightly adjusting your tyre pressure will have 10x the impact of any possible difference in frame material.

My basic argument is just that it is plausible that the perceived different feel of different frame materials is real, and that there is no support for the claim of another comment that a different feel is impossible. I am surprised that no one seems to have done any convincing experiments.

I could have left out my anecdote because it is subjective and prone to bias and error, but it is how I believe I can rule out (some of) the commonly cited reasons of different bike feel -- seat posts, because that would not affect vibrations coming through the feet; and tire pressure, because different tire types and pressure have their own different and recognizable feel (e.g. responsive and jittery with high pressure, squishy and sluggish but not silky smooth with low pressure).