Originally Posted by
Eric F
Same frame size - both bikes fit me with the same length stem and a similar amount of exposed seat post.. I haven't measured, but the wheelbases are probably pretty close. These are both race bikes with tight rear ends. I think the aluminum bike has a slightly slacker head tube angle, but probably by less than a degree. The most noticeable difference I feel between the two is in lateral stiffness under heavy power, but there is also some difference in the smoothness of the ride.
Posts here (including your most recent post, quoted above) have had me starting to doubt myself. Am I somehow wrong---are there indeed real differences in vertical compliance between aluminum and steel frames---differences I can't detect because of some deficiency in my powers of perception? (The late Sheldon Brown stated flatly decades ago that there are no such differences, but he could have been wrong, too, I guess.)
So I just now did a search using something like "measured differences in vertical compliance between aluminum and steel bike frames" and found many results. (The link at the bottom of this post is to one of a number of reports with similar conclusions.)
From what I read in several of those reports, the numbers indicate that there isn't enough vertical compliance in any bike, regardless of frame material, to differentiate it from any other (broadly similar) bike.
Not saying that the people who swear that aluminum bikes rattle your fillings out and so on don't really perceive that. But the numbers would seem to suggest that there's little more than confirmation bias behind those perceptions. Or, if not that, that the bike with the "harsher ride" has a shorter wheelbase.
Whenever yet another discussion of bike comfort versus frame material shows up on Bike Forums, I always immediately look for a mention of the bike's wheelbase as a possible contributory factor. But I rarely or never see any discussions that touch on the significance of a bike's wheelbase for its riding characteristics. The wheelbase seems to be universally thought to be what it is merely as a consequence of other, far more significant geometry decisions. But I think it's the other way around---that it's the chosen wheelbase that determines how the bike rides.
A comparison from my own fleet of bikes (and from my 55 years of riding first pro-level steel and then aluminum and carbon road and track bikes and thinking about this topic):
My Specialized Langster track bike (aluminum frame with large-diameter tubing, aluminum straight-bladed fork with large-diameter tubing, more or less standard road bike racing geometry) has a 98-cm wheelbase.
My Felt TK2 track bike (aluminum frame with large-diameter tubing, carbon straight-bladed fork, standard track racing geometry) has a 94-cm wheelbase.
I don't feel any difference between the bikes in vertical compliance ("comfort"). But the handling of the Felt is hair-raising (except at racing speed). Given that the Felt requires constant attention because of the rapidity with which it reacts to steering input, I don't find riding it on the road comfortable at all. It's spectacularly fast. But "relaxing" is about the last term I'd use for the riding experience.
For what it's worth, I'd describe the ride of the Bianchi steel track bike I rode in the 1980s the same way. The Langster, on the other hand, is my all-time favorite bike. I absolutely love how it rides.
I'll now shut up about this and suggest looking at the information in the linked article.
https://www.cyclingabout.com/why-imp...han-aluminium/