Originally Posted by
mstateglfr
The frame doesnt generate heat when in use? Boy I would figure it does, but the heat is minimal and is cooled relatively quickly.Frame flex probably doesnt rob a rider of 'much' power and acceleration, but you have to agree that energy is absolutely being lost going to the drivetrain to propel the bike forward when the frame twists while pedaling. More twisting = less energy that is concentrated on moving the bike forward. It takes energy to deflect the frame and that energy is 'lost'.
We're way outside of my wheelhouse, so I'm never going to argue these points...Just throwing this out there for discussion.
Since the steel frame doesn't actually bend under power, it's acting more like a spring: it might flex in one direction (dissipating power) and then flex back in the other direction (returning power). To come back to physical laws: the Second Law of Thermodynamics does imply that some power will be lost in the process, but probably not much. (If power is lost, the First Law suggests that it must go somewhere outside of the system - and as you acknowledge, there is probably not much heat being generated. So, what happens to the power? It doesn't just vanish.)
To get to the broader point, the OP's concern about acceleration: it is entirely possible to build a very stiff steel frame, but it'll be a bit heavier than a comparably stiff ti frame, and quite a bit heavier than a comparably stiff cf frame. And that weight will slow acceleration. (Again, because of physics...Some stuff about mass and velocity, and blah blah blah.) So, frame material is only part of the issue.
For what it's worth, my steel-framed gravel bike is very stiff -- almost too stiff, I sometimes think. On the other hand, my friend has a ti framed-bike with a 1x drivetrain, and it's so flexy that, by simply standing and sprinting, he can make the chain come off the chainring. So, again, it's not all about the material alone.