Tire size equivalent chart for 33", 35", 37" or 40" tires

Our tire experts often get questions about the sizes that are considered a 33", 35", 37" or 40" tire. These numbers are referring to the older tire sizing system known as “Flotation” sizes. These days we also have similar tire sizes in the metric tire sizing, which makes the decision on what size tire will fit your rig downright confusing. Not all tires are exactly the height or overall diameter that they state to be. It might say it is a 35X12.50-20, but the actual diameter noted in the specs is 34.6". The chart below should give you a good idea for the various tire size equivalents for popular truck sizes. Tirebuyer has one of the largest selections of All Terrain and Mud Terrain tires in stock ready to ship fast and free.

33" Tires (+/- 0.50" in overall diameter)
15" 16" 17" 18" 20" 22"
33X950-15 285/75-16 275/70-17 275/65-18 285/60-20 285/50-22
33X10.50-15 305/70-16 255/75-17 275/70-18 295/55-20 33X12.50-22
33X11.50-15 375/55-16 285/70-17 305/60-18 305/55-20 305/45-22
33X12.50-15M 305/65-17 295/65-18 325/50-20
33X13.50-15 33X12.50-17 33X12.50-18
33X15.50-15 325/60-18
375/50-18
35" Tires (+/- 0.50" in overall diameter)
15" 16" 17" 18" 20" 22" 24"
35X12.50-15 315/75-16 315/70-17 285/75-18 275/65-20 35X12.50-22 325/45-24
295/70-17 295/70-18 285/65-20 325/50-22
35X12.50-18 295/65-20
305/70-18 315/60-20
325/65-18 325/60-20
35X11.50-20
35X12.50-20
35X13.50-20
37" Tires (+/- 0.50" in overall diameter)
15" 16" 17" 18" 20" 22" 24"
37X14.50-17 385/70-16 37X12.50-17 37X11.50-18 37X12.50-20 37X12.50-22 315/50-24
37X12.50-18 37X13.50-22 37X13.50-24
37X13.50-18
40" Tires (+/- 0.50" in Overall Diameter)
17" 20" 22" 24"
40X13.50-17 40X15.50-20 40X15.50-22 40X15.50-24
33" Tires (+/- 0.50" in overall diameter)
15" 16" 17"
33X950-15 285/75-16 275/70-17
33X10.50-15 305/70-16 255/75-17
33X11.50-15 375/55-16 285/70-17
33X12.50-15 305/65-17
33X13.50-15 33X12.50-17
33X15.50-15
18" 20" 22"
275/65-18 285/60-20 285/50-22
275/70-18 295/55-20 33X12.50-22
305/60-18 305/55-20 305/45-22
295/65-18 325/50-20
33X12.50-18
325/60-18
375/50-18
35" Tires (+/- 0.50" in overall diameter)
15" 16" 17" 18"
35X12.50-15/td> 315/75-16 315/70-17 285/75-18
295/70-17 295/70-18
35X12.50-18
305/70-18
325/65-18
20" 22" 24"
275/65-20 35X12.50-22 325/45-24
285/65-20 325/50-22
295/65-20
315/60-20
325/60-20
35X11.50-20
35X12.50-20
35X13.50-20
37" Tires (+/- 0.50" in overall diameter)
15" 16" 17" 18"
37X14.50-17 385/70-16 37X12.50-17/td> 37X11.50-18
37X12.50-18
37X13.50-18
20" 22" 24"
37X12.50-20 37X12.50-22 315/50-24
37X13.50-22 37X13.50-24
40" Tires (+/- 0.50" in Overall Diameter)
17" 20" 22" 24"
40X13.50-17 40X15.50-20 40X15.50-22 40X15.50-24