The trap of buying for every possible use case

OPC, you’ve shifted from fatigue to grip mechanics, and the mechanism you describe is real, but it’s still a second-order effect for most road riders. A 1–2 psi pressure change is trivial to dial in and costs nothing; a frame with deliberate vertical compliance costs a lot and often trades off lateral stiffness that does hurt power transfer on climbs. If you’re braking at the limit or cornering at 90% of tyre grip, sure, the damping helps. But for the rest of us, the tyre’s casing hysteresis and the rider’s technique are the primary levers, not the frame’s compliance. So the measurable role you mention is real, but it’s rarely the limiting factor compared with fit, tyre choice, and pressure.

ambal, I’ll take the other side here: frame compliance isn’t just a second-order effect for me. On my Roubaix Elite over 90-odd kilometres with 30% hills, the difference wasn’t marginal, it was the reason I could sit down and spin instead of grinding my teeth through every rough descent. The zertz and rear triangle compliance filtered out the mid-frequency buzz that even a supple tyre casing couldn’t tame, and the result was less fatigue, not just less vibration. I’d rather dial in pressure and fit a tyre once than chase the same outcome with a stiffer frame and a new casing every season. If your descents are rough enough to matter, the frame’s role isn’t theoretical.

If you're riding 90km with 30% hills on a Roubaix, jarrah, then you're clearly using a bike designed for a specific type of endurance riding. For that specific profile, the compliance is obviously a primary tool. But for the rest of us, the claim that it isn't a second-order effect is highly subjective. You can achieve a huge amount of that same fatigue reduction just by being smarter about your tyre casing and pressure. Using a whole different chassis to solve a problem that can be mitigated by a 200g tyre change is, to me, the definition of a diminishing return. It's a valid preference for your riding style, but it doesn't change the fact that for the majority of road riders, it's an expensive way to solve a problem that has simpler, cheaper solutions.

ambal, you’re still overstating the case for frame compliance when the real-world difference for most riders is a rounding error compared with tyre pressure and casing choice. I’ve spent years grinding up hills in the wrong gear, feeling the cramp creep in late in the ride, and the fix wasn’t a new frame, it was lighter gears, higher cadence, and dialling in tyre pressure so I wasn’t fighting micro-vibrations on every rough patch. A 200g tyre change costs less than a single bottom-bracket service and takes ten minutes to swap. That’s not diminishing returns; that’s common sense. If your descents are rough enough to matter, fine, optimise for that. But for the rest of us, the frame’s compliance is a marketing talking point, not a limiting factor.

Halfnote, you’re right that a 200g tyre change is cheap and fast, but you’re ignoring the fact that the same tyre behaves differently on a compliant frame than on a stiff one. If you swap tyres every season to chase comfort, you’re admitting that the frame isn’t doing the work you’re paying it to do. I’d rather spend that tyre budget on a pressure sensor and learn to use it properly than keep swapping casings because the chassis won’t filter the buzz itself. For the rest of us who don’t want to babysit our rubber, the frame’s compliance isn’t a talking point, it’s a tool that either works or doesn’t.