Having given my enthusiastic general support to this report, it is time to mention a rather serious quibble.
The reporter starts off by saying that roadies have always thought that the harder the tyre is inflated, the easier it is to propel, and that mountain bikers thoughtlessly transferred this preference to offroading. So far, so good. (1)
After the tests are in, he then concludes that offroad tyres should be wide and only modestly inflated. That too is right.
Then, for on-road tyres, he makes the same mistake he rightly accuses the reactionary roadies of.
Apparently his "authority" for this error is the graph on p7 (2), labelled "The influence of tyre pressure". It shows a dramatic fall in rolling resistance as the inflation pressure falls on gravel, a lesser slope but in the same direction on grass, and a still lesser but opposite slope on the road.
Actually, his conclusion in relation to on-road pressure is already a mistake from this evidence alone. Eyeballing the graph, the difference between 2bar -- which the maximum to which I and many others inflate 2.35in/60mm Big Apples to carry heavy bikes and heavier riders with even heavier loads, and 4 bar -- is about 5% cost in rolling resistance power.
Another graph shows us that on the road rolling resistance represents only about 12% of power consumed. So what we're talking about is a power cost of about 0.6% extra. That's a trivial cost for all the other benefits in comfort, roadholding and handling from using the lower inflation.
It's already a ludicrous conclusion from a very small margin. If I didn't like the rest of this fellow's article so much, I'd condemn him for not putting his brain in gear. Unfortunately there's more, that any experienced cyclist will immediately see:
But that's on a test track's ultra-smooth road surface. On any rougher road, such as is found in real life, the rolling resistance disadvantage will almost instantly tilt the other way, towards the off road condition, towards an advantage. So now, for real roads, one chooses the low-pressure balloon in its own right, and again comfort, roadholding and handling factors tend the same way.
Still not the whole story. The tests were taken at 5km to eliminate wind resistance considerations. (Unnecessarily so in my opinion, but never mind.) The point is that the higher the speed -- and road speed is certainly higher on average than either 5kph or 5mph -- the greater the rolling resistance advantage of all low-pressure tyres, and the correspondingly greater the comfort, roadholding and handling advantage of balloons.
The reasons to fit balloons on a bike for use on the road, and to keep the inflation low, are overwhelming when you put your mind in gear, including on this evidence which at first sight can be (and by this fellow is) read the opposite way.
QED.
FOOTNOTES
1. It isn't quite that simple, but never mind. The real story has to do with beach cruisers, which already had low-pressure slick balloons, giving birth to mountain bikes, and mountain bikes being perverted by ignorant marketing fashions over the decades, but, as I say, never mind the truth, we'll go into it some other day if anyone cares.
2. For some reason my Mac won't copy or save this PDF from Safari, nor mail it, nor anything, so my page numbers refer to what Safari shows.
