Brucey wrote:I struggle with this whole argument because on the one hand I know what Colin says is true, yet wheels appear to feel different to me, too.
Thinking out loud here, what if the loads are much more than 50kg? What does 'the system' actually look like that passes road bumps into the handlebars?
On the first point suppose you run over a bump at ~20mph. 700C wheels are doing about 5 revolutions per second, and the bike will go up (and maybe down again) in something of the order of 100 to 200mm of distance, or about 1/100th or 1/50th of a second. I suspect that the forces required to do this are somewhat larger than 50kg and maybe the wheel deflections are larger too.
On the second point the tyre, the wheel, the fork(or frame), and the handlebars(or saddle) are each a spring in series with the next spring. The mass is distributed between these parts too. The behaviour of such systems is complicated; each element has its own resonant frequency and impulses introduced at one end of the system will pass through in various different ways depending on how the system reacts as well as the nature of the impulse.
So maybe, if a flexible rim deflects twice as much as a stiff one, you mightn't expect to 'feel the difference in the deflection' per se but if that change is accompanied by a x2 change in the resonant frequency of part of the system, it might alter what kinds of vibrations are passed through to the handlebars/saddle and are then felt by the rider.
-just a thought, anyway....
cheers
I imagine that 50Kg was simply a load that Brandt could use in his test rig. Even if real life loads over a bump were 4 times that, a vertical wheel deflection of 4 times 0.15mm still isn't a lot.
All the bits in the system will flex in response to a bump, lets have a stab at putting them in order of which flexes the most to which flexes the least.
My guess;.......saddle /tyre / fork / handlebar / frame / wheel .......
I think the wheels are down there among the least vertically compliant things in the system, and it seems perverse (to me) to go looking for "improvements in comfort" from the wheels.
What feels good riding your bike is notoriously subjective....my bike goes much better when its clean and the sun is out. Some say their bike feels much faster without mudguards. Jeremy Clarkson says red cars are faster.
I think your light wheels feel better because you put them in when you expect to have a good day, and also you expect them to feel better.