P35/12.5 R18 is 18.34 in inches Section Width: 35 mm Rim Diameter: 18" Sidewall Height: 0.17" Circumference: 57.62 " Revs per Mile: 1099.62/mi Forthe 33×12.5r18 tire, a close metric equivalent is 315/60R18. This indicates a width of 315 mm, an aspect ratio of 60% (indicating the sidewall height is 60% of the tire’s width), and a wheel diameter of 18 inches. Practical Applications. The 33×12.5r18 tire size is trendy among off-road enthusiasts and is often seen on 4×4 trucks and SUVs. Notall 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 23535-R18 tires are 0.93 inches (23.5 mm) smaller in diameter than 235/40-R18 tires and the speedometer difference is 3.6%. 37X135R18 tires are 37.0″ tall, have a section width of 13.5″, and fit wheels with a diameter of 18. The circumference is 116.2″ that translates into 545 revolutions per mile. As a rule, they can be mounted on the wheels with 18″ x 8.5-11″ rim width. In the metric system, the equivalent tire size is 343/70/R18. 22560 R18 vs 235/50 R18. 185/60 R15 vs 195/60 R15. 215/65 R16 vs 225/60 R16. 215/70 R15 vs 205/75 R15. 235/65 R18 vs 245/60 R18. Tire size conversion and comparison. Janu. 775 Views 0. 31X12.5R16 tires are 31.0″ tall, have a section width of 12.5″, and fit wheels with a diameter of 16. The circumference is 97.3″ that translates into 651 revolutions per mile. As a rule, they can be mounted on the wheels with 16″ rim width. In the metric system, the equivalent tire size is 318/60/R16. Iwill be upgrading to larger tires from my 32" stock tires, likely onto new 18" wheels. The overall diameter of the Nitto Trail Grappler M/T, LT295/70R18 is 34.57", while the diameter of the Nitto Trail Grappler M/T, 35x12.50R18LT is 35.04". The kicker is it'll run me an extra $235 for four "true" 35's as opposed to the LT295s. 7EPJ.