They are typically used to describe the same size: 650 mm section width, 80 profile, and a 16 inch rim diameter. The key difference is construction, because the R in 650/80 R16 indicates radial. If your existing tyre shows a dash and also states Radial on the sidewall, you can normally match it with 650/80 R16, but always confirm the full sidewall markings before buying.
650/80 R16 fits a 16 inch diameter rim, but rim width can vary by manufacturer and tread design. Many fitments use a wide implement-style wheel, and the exact approved rim width will be listed in the tyre’s technical data. Check the wheel stamping or measure the rim, then match it to the manufacturer recommendation to avoid bead seating issues and uneven wear.
Start with the heaviest real working condition: maximum payload, liquid surge for tankers, drawbar weight transfer and road speed. Then choose 650/80 R16 with a load index that covers the per-tyre load at your intended inflation pressure, with a sensible safety margin for uneven fields and potholes. If you are unsure, note the axle rating, number of tyres, and typical transport speed, then select a load rating that meets or exceeds the requirement.
It is best not to, especially on the same axle. Mixing a 650/80 R16 radial with a bias-ply equivalent can change rolling circumference, sidewall deflection and how the tyres share load, which can lead to scrub, heat build-up and unpredictable handling. For consistent braking and tracking, replace in pairs on the same axle and match construction, size, and tread pattern wherever possible.
Use the manufacturer load and inflation table for your exact 650/80 R16 model, because the correct pressure depends on load, speed and casing specification. As a rule, heavier loads and higher road speeds require higher pressures, while field work may allow lower pressures to increase footprint and reduce soil compaction. Do not run below the minimum recommended pressure, and recheck pressures cold before long road runs, as underinflation is a common cause of sidewall damage on high-volume flotation tyres.
