Originally Posted by
HTupolev
To the right. Higher load needs more stiffness in a suspension system to create the same amount of vertical interaction. More pressure for the same sag, more force to create a given amount of vertical deflection in the sprung mass. Same reason that suspensions on mountain bikes are tuned stiffer for heavier riders.
Sorry, i was sloppy in my question - it should have up/down (not left/right) - ie, for a given pressure, is resistance loss higher or lower for a heavier rider? I agree that the actual deflection would be lower for a heavier rider (same force, greater mass) - but how about the actual energy loss? A heavier rider imposes a greater downward force on the system, which results in a greater counter-force - so i would imagine the resistance loss would be higher. In other words, the curve would shift upwards.
Would you agree with that?
The big issue is that optimal setup is a highly multivariate problem, and the differences that need to be measured to give real answers are very small. It would take a pretty broad study to thoroughly sort things out with good accuracy and precision, and the cycling industry just doesn't have a very large or unified R&D budget.
Yeah, true enough.... but there seems to be a very strong degree of certainty behind this argument and a similar commitment to wider wheels. So they must have some science behind it. And good question about the shape of the curve too.
Originally Posted by
Branko D
My hunch is that brands are pushing wider tires because the average customer isn't the light, young racing type.
If you're reasonably light - 65 to 75kg - and want comfort, you can simply ride 23s or 25s at less pressure. At 90 psi they offer a much more muted ride and I found myself even faster on bad roads with around 80 psi.
But for the average customer, 28mm tires may be needed to be able to use comfortable pressures.
I agree with this but up to a point. Just as bike brands have racing models and endurance/sportive models, one would expect them to have separate "comfort/balanced riding" and "max speed" wheels - I wouldnt expect the industry to give up speed-maximized wheels entirely, you know?
And in any case, the Silca chart was with 190lb system weight, so not superlight either.
It could be that the industry is betting on all-road being the future - these new wheels are certainly ideal for that. And as generalist wheels to handle all sorts of road conditions, it makes sense too - on rougher roads, the inflection point could be a lot lower.
But does that mean for those of us who do ITTs and triathlons on good roads, an older-gen road wheelset with, say 25c tires run at 85psi, would be faster?
I have been having an existential crisis because the 23mms mounted on my old HED Jet 9s measure a little bit larger than the rim, and i am positive this is the ONLY thing keeping me from winning my AG in 70.3s. But i am afraid of angering The Merckx by going against the "wider = better" trend.