[danburbridge]

I am not suggesting that all 23c tyres are cheap, but that tyre quality (which comes at a cost) as well as size has an important part to play in comfort.

My 23c handmade FMB tubulars (definitely not cheap) are a much nicer ride than cheaper tyres.

Rolling resistance is far more complicated, on anything other than a wooden velodrome, the road surface actually means that there is a sweat-spot in terms of pressure - too low and rolling resistance will be high, as you say, this decreases up to a point at which the effects of the microbumps in the road start to cause energy losses through hysteresis and eventually the tyre bouncing over tiny bumps.

For a 23c tyre and a 70kg rider the optimum tyre pressure is actually typically in the 80-90psi range (5.5-6ATM) although again this is dependant on tyre quality, an expensive tubular tyre with very supple silk sidewalls can be run at higher pressure than a touring tyre with tough reinforced sidewalls.

[Yetanfou]

I don't know how much you ride and in which conditions so I can't comment on the choice of your un-cheap 23c handmade FMB tubulars. What I do know is that those would not last very long for me, handmade magic pixie dust notwithstanding. I ride year-long through the Swedish countryside with temperatures ranging from a maximum of 37°C to -25°C, on roads which vary from reasonable to hard to find on map and landscape. I mostly ride a steel-framed 24-speed with 47-622 knobbly tyres (in other words "fairly fat tyres on 28" rims) at around 5 atm. as those give both speed as well as traction. Microbumps and similar concerns don't apply here, the bike is meant to take me from A to B no matter how many picobumps I encounter. Still I average around 30 km/h on the flat, easily reach 50 km/h downhill.

In other words, I use my bike as I use my motorbike: as a form of transport. Maybe that takes a different approach, maybe not, as said I don't know how you use your bike. What I do know is that I generally don't hold with the 'cultures' which form around specific areas, no matter whether it is biking (silk-walled handmade tyres adapted to your personal preference), audio (audiophile-grade left-turning 99.999999% oxygen-free oriented-strand meteoric copper power cables), food (organic free-range lettuce grown on virgin soil from heritage seeds fertilised with certified manure from Swiss highland cattle) and other such things.