about OTR tires

a.  T.R.A. Classification and application

 b.  The different Off-The-Road Tire families.

100 Series ( Narrow Base )
The H/S aspect ratio is approximately equal to 1.00
The section width, given in inches is a whole number
Example: 18.00R25                                

80 Series ( Wide Base )
The H/S aspect ratio is approximately equal to 0.80
The section width, given in inches is a whole number followed by a fraction
Example: 20.5R25= 525/80R25

65 Series (Low Profile Tires )
The H/S aspect ratio is approximately equal to 0.65
The section width, given in millimeters followed by the number 65
Example: 750/65R25 

c.   Comparison of tread depth