There is a compromise. You're only considering rolling resistance. 42mm tyres are significantly less aero than 23mm and this will be a not insignificant drag at higher speeds.
And if one's using aero rims, there's none optimized for such fat tyres.
I have no idea about aero, but there's quite some 25mm plus internal aero rims? 3t discus for example.
@c.h.e. started
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And if one's using aero rims, there's none optimized for such fat tyres.