Construction Meaning of Loaded Radius
Static loaded radius is the distance from the wheel center to the ground while the tire carries load. It is smaller than the unloaded radius because the sidewall bends. On construction projects, this number affects machine clearance, trailer deck height, fender spacing, grade transitions, and ground contact estimates.
Why It Matters On Site
A tire may look tall when measured without load. After a loader, telehandler, compactor, or service truck is loaded, the tire settles. That settlement changes the height of axles, steps, attachments, and underbody parts. A small error can cause rubbing, inaccurate leveling, or poor haul road clearance. This calculator helps compare measured deflection with an estimated value based on sidewall height, pressure, and wheel load.
Input Quality
Use the tire size molded on the sidewall when a shop measurement is not available. Enter rim diameter in inches because most tire designations use that convention. Measure actual outside diameter when the tire is worn or oversized. Enter axle load from scale tickets, equipment manuals, or project load calculations. Add uneven load share when buckets, booms, trailers, or side slopes shift weight toward one tire.
Using Deflection Methods
Direct deflection is best when you can measure the tire under working load. Percent sidewall deflection is useful for planning. The estimated method is only a practical planning model. It uses tire load ratio, pressure influence, and site ground factors. It should not replace manufacturer engineering data or final field measurement.
Construction Checks
Loaded radius supports several layout checks. It helps verify ramp breakover points, dock approach height, mudguard clearance, equipment transport height, and working ground clearance. The contact patch estimate can support temporary surface review. Higher wheel load or lower pressure usually increases deflection. Softer ground may also increase effective settlement.
Best Practice
Calculate several cases. Use empty, normal, and worst load conditions. Compare new and worn tread. Save the CSV for project records. Export the PDF when the calculation must be attached to a site method statement, equipment checklist, or lifting plan. Document assumptions clearly. Keep unit choices consistent. Recheck pressures before heavy movement. Share results during prestart planning. Repeat measurements after service. Always confirm important clearances with a field measurement before work starts.