A tale of two tyres (or four or six)
Ignorance was bliss: I thought I was happy with Brown Bike's Schwalbe Marathon 28mm tyres.
I have heard that, when everything else is equal:
(a) Wide tyres have less rolling resistance than narrow ones.
(b) Tyres at high pressure have less rolling resistance than at low pressure.
(c) Tyres at high pressure are less comfortable than at low pressure.
(d) Pressures make some difference to puncture probability but, snakebites aside, people disagree about which way it goes.
Brown Bike has always worn the widest he can, 28mm, so (a) was irrelevant to me. My old track pump wheezes at 85 psi, so that's what I've been giving the rear tyre with a little less in the front. I'm not a speed-freak and I've never Joggled, although I'm aware that fellow-blogger Mick is happy touring on anorexic tyres. But he's a fitter, hardier cyclist than me, so that wasn't relevant either.
So far so good. I was happy and Brown Bike was happy. True, his sister Ruby is sleek, sexy and fast, but she's lighter and not encumbered with heavy D-lock, rack and mudguards. She's a racer, not a tourer. She runs on 23mm tyres, and I was pleased to find they were not grossly uncomfortable. She tends to slip on hoggin surfaces, but I avoid those.
Then I bought a secondhand pair of wheels to go on either bike. They are "just in case", an insurance policy. I had to test them out, so swapped them on to BB. They worked fine for a lap of the village green, so we went shopping. No problem, and to my surprise BB felt exactly as before. Schwalbe Marathons (28mm) and Specialised All Condition Armadillos (23mm), at the same pressures, on roads, seem to have equal comfort levels.
Lidl sold me a track pump for the princely sum of £4.99 that turned out to be better than my old one, and easily capable of squeezing 125 psi into the 23mm Armadillos. So we trotted off again. But it must be spring, because BB took off like a bicycle re-born. He sprinted off with ants in his pants; I couldn't hold him back. I exagerate slightly, but there was no doubt that shoving an extra 50% of pressure in his tyres greatly reduced the rolling resistance.
Of course, the gravel on my drive pinged away like bullets as we rode out. And, of course, the nail-hard tyres were agony to ride on, weren't they? Actually no. They might have transmitted slightly more vibration but nothing worth complaining about. Besides, Lidl has also supplied comfortable padding for my posterior.
My informal trials have confirmed points (a), (b) and (c) above. I'll try to do something a bit more scientific, like Mick's Gunnislake Station roll-out tests, but my current thoughts are:
(a) If 28mm Marathons have less rolling resistance than 23mm Armadillos (at the same pressure), I don't notice the effect.
(b) Armadillos at high pressure have far less rolling resistance than at low pressure.
(c) Armadillos at high pressure aren't much less comfortable than at low pressure.
(d) No evidence yet about punctures.
Point (c) is subjective, and anyhow my comfort level falls when I'm knackered, so a tyre that gets me there with less effort could be more comfortable overall. Point (d) couldn't be established in less than a zillion miles.
These particular Armadillos are too worn to consider taking to Yorkshire, so I'd have to get new ones. Or narrower and higher-pressure Marathons. Or something else that likes high pressure. True, BB looks somewhat ill-shod in anorexic tyres, and they might not suit muddy Yorkshire moors. I have discovered that the Lidl track pump fits neatly under his top tube, if I can figure out where to put the D-lock. Or maybe we'll leave that at home.
Is Brown Bike turning into a boy racer? Perhaps, but he needs a stronger motor. I did 36 miles today at a paltry 10 mph.