There is a lot of hype and misinformed discussion about rolling resistance, when it comes to comparing different brands of tyres. Can it not be measured? Would it be so hard to perform experiments where different tyres are mounted on the same wheel, and the friction at various speeds measured?
It seems to me the variables are:
- kind of tyre, including width
- weight over axle
- surface of road
I'm not sure whether air resistance should be considered.
But anyway, you could hold all the variables above constant, and for each tyre, produce a statement like "Has a rolling resistance of 153 xxx when inflated to maximum recommended pressure (xxx psi), with 40 kg over the axle, on a smooth tarmac road of type xxx, at 25kph."
Has anyone seen anything like this? What's the difficulty?