Dually truck tire replacement
Have an F350 dually with tire size LT 245/75R17 121/118R Obviously I need same diameter. Wonder how important aspect ratio is to match current tires (original are Yokohama tires)
Forum Discussion
paulbeauchemin wrote:parker.rowe wrote:
Aspect ratio? As in the "75" in that tire size?
That is pretty important. It IS the tire height.
245=tread width in mm
75=sidewall height as a % of tread width. ex: 245 x 0.75=183.75mm
17=rim diameter in inches
So...
total sidewall height in mm = 183.75*2=367.5
total sidewall height in inches = 367.5/25.4=14.47 inches
total diameter = 14.47+17 = 31.47 inches
Of course, there are discrepancies from tire to tire and manufacturer to manufacturer. But that is what the numbers are suppose to mean.
I see - if replacing just one of the tires in a dually that this would be critical
But if you replace all 4 is aspect ratio critical?
No, it's not. Neither is diameter within reason. Small change in dia will be indiscernable. Even a couple inches in dia will not make much difference.
I'd run 255-80-17s. A little extra meat on the rims would be nice compared to 245s.
