My work commute pickup, I run Nitto 420D's (275/55R20)
Rarely do they see under 120km/h on the motorway (Mon to fri 150km round commute each day) and they have 60,000 km on them thus far.... I reckon i'll get another 15k outta them.
I doubt they would go 240,000+ if I stayed under 120km/h.