A flotation label such as 30 × 10-14 describes nominal outside diameter, nominal section width and wheel diameter, in inches. Each number answers a different question. Moving from a 30-inch to a 32-inch tire does not say whether the new tire has the same width, rim requirements or clearance at full steering lock.
Keep the tire and wheel diameters separate
In the example label, 30 inches is the tire’s outside diameter and 14 inches is the wheel diameter. The geometric sidewall estimate is (30 − 14)/2 = 8 inches. A 30 × 10-15 gives 7.5 inches in that simple calculation. This is a geometric estimate, not a measured loaded sidewall or a performance recommendation. Different rim diameters require corresponding tire bead sizes.
Width and wheel width are different specifications
The tire’s labeled section width does not give the wheel’s approved rim-width range. Consult the tire maker’s rim specifications and the vehicle maker’s approved setup. Wheel offset and width can move the tire toward suspension parts or outside the body. Wider tires may change the machine’s overall transport width. A calculator using only labeled width cannot evaluate that full assembly.
Read radial markings without losing the dimensions
A label such as 30 × 10.00R-14 includes “R” for radial construction. Our Wolverine RMAX2 Sport record retains that source explanation while normalizing nominal dimensions to 30 × 10-14 for calculator input. Normalizing the numbers is not a claim that construction types are interchangeable. Check the complete approved specification.
Measure under comparable conditions
Compare mounted tires with equivalent measurement methods and documented conditions. Pressure, load, wheel dimensions and tread condition can affect measured size. The label is a useful starting point for tire comparison; a measured diameter may better describe a speedometer scenario. Do not mix an unloaded manufacturer dimension for one tire with an unrelated loaded measurement for the other.
Can the calculator confirm fitment?
No. It does not model wheel offset, rim width, steering travel, suspension articulation, fender space or braking components. Match the exact year and trim, consult manufacturer guidance and inspect the complete assembly with qualified help. Follow load and speed ratings and applicable restrictions. The original tire-label guide remains a useful introduction.
What is the next useful calculation?
Compare outside diameter first, then review theoretical clearance and effective gearing. Finally re-measure trailer width with the actual wheels and tires installed. A stock specification page describes stock equipment; an owner’s modified machine needs its own measurements.