John, where did the figs of 38/42 come from? I too would have thought that was very high, unless 2-up and fully laden. I tend to think of my defaults as 32/34, though as you say sportier/trackday riders often go for less, the calculation simply being that with the pressure lower (eg dropping a Diablo from 32/34 to 29 both) you'll get heat into them quicker, and that grip rather than durability is the issue. I always think that the tyre manufacturers' psi recommendations need to be consulted: many people stick with what's quoted in the bike manual, but it seems to me that that's only good for the tyres it actually came with, and that what Ducati thought was good for the Dunlop-Whatevers my SS came with in 1997 might not be right for Pirelli Diablo Rossis over a decade later. It's easy enough to check tyre manufacturers' recommendations these days too - some have that facility online (I know Pirelli do).
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