Originally Posted by
Spoonrobot
Source?
The article is from Bicycle Quarterly and is basically the same 15% figure from Frank Berto that's been rolling around since the late 1980s. I can't find any retraction or anything else?
It's not the 15% so much as the assumptions over weight distribution.
Other than that, regarding the 15% I've seen what looks like different amounts of deflection depending on the tire - I suspect that it's the construction and sides specifically. Also, my observation, with respect to rolling resistance the cheaper but more flat-protecting tires have a point where lower pressure starts really making it drag, as opposed to more supple higher performance tires. I think that there are a lot more "it depends" than this chart would have it and you eventually get back around to choosing pressure for a given tire and given person by experience, or leveraging from someone else's experience.
Just take it all with a grain of salt.