Ok guys stupid question but i am having a hard time figuring this out. I have looked on rockauto to order some front rotors for my 88 dodge ram 50 2wd. All the rotors they say are a 6 x 104mm bolt cirle which is 6 x 4.???in. BUT when i measure my lugs from center bolt across i am coming up with 6 x 5.5in??? Any ideas