The different OTR 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
Our size list:12.00R24, 13.00R25, 14.00R24, 14.00R25, 16.00R25,18.00R25, 18.00R33, 21.00R33, 21.00R35, 24.00R35, 27.00R49, 30.00R51, 33.00R51, 36.00R51, 40.00R57
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
Our size list:15.5R25，17.5R25，20.5R25，23.5R25，26.5R25，29.5R25，29.5R29
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: 875/65R29
Our size list: 600/65R25，650/65R25，750/65R25， 875/65R29, 35/65R33, 45/65R45
How to Read Tire Sizes?
What does each digital or letter in a tire size mean?
Overall Diameter (OD)
“Overall Diameter” is twice the section height of a new tire, plus the nominal rim diameter, including 24-hour inflation growth.
Overall Width (OW)
“Overall width” is the width of a new tire, including 24-hour inflation growth, and including protective side ribs, bars or decorations.
Section Width (SW)
“Section Width” is the width of a new tire, including 24-hour inflation growth and including normal sidewalls, but nor including protective side ribs, bars, or decorations.
Static Loaded Radius and Width (SLR, SLW)
“Static Loaded Radius” is the shortest distance from the axle center to the contact surface of a tire and “Static Loaded Width” is the overall width of a tire, mounted on the approved rim at the specified inflation pressure and placed still and vertically on a flat board, and loaded with the specified load.
Original Tread Depth (OTD)
“Original Tread Depth” is the tread depth of a new tire measured at the point of tread-indicator where available or one-fourth the width of the tire crown section from the crown center, including 24-hour inflation growth.
23.5 R 25
23.5 Section Width (inches)
R Radial Construction
25 Rim Diameter (inches)
29.5 -25
29.5 Section Width (inches)
– Bias Construction
25 Rim Diameter (inches)
385/95R25 170E
385 Section Width (mm)
95 Aspect Ratio (95%)
R Radial Construction
25 Rim Diameter (inches)
170 Load Index
E Speed Symbol
35/65R33
35 Section Width (inches)
65 Aspect Ratio (65%)
R Radial Construction
33 Rim Diameter ( inches)
50×20-20
50 Overall Diameter (inches)
First 20 Section Width ( inches)
Second 20 Rim Diameter ( inches)