This is what tirerack.com says for NT555RII
SELECTED SIZE
Size: 275/60R15
Service Description:107V
Load Index 107= 2,150 lbs (975 kg) per tire
Speed Rating “V”= 149 mph (240 kph)
Load Range:SL
Max. Load= 2,149 lbs
Max. psi= 51 psi
UTQG:100 A A UTQG
Max. Load:2,149 lbs
Max...