'Upgrading' to skinny tyres pointless for London commuting

Wider tyres have lower rolling resistance, this have been around for quite some time, it's just conventional wisdom that narrower, firmer tyres = better performance.

Actually I said lower rolling resistance, I said nothing about it being better in performance.

O rlly Ed? And if you reckon you were just talking about rolling resistance, and 'conventional wisdom' talks about better performance, you're conflating the issue, at best.

Boonen was on Vittoria Pro-Team Special Pave 25mm (the ones with the green sidewalls) for his last few Paris-Roubaix, I don't know about yesterday.