TireSizesFinder

265/60R20 vs 275/50R21

275/50R21 is 0.69 in (17.6 mm) shorter than 265/60R20, a −2.13% diameter difference. With the speedometer set for 265/60R20, an indicated 60 mph is 58.7 mph on 275/50R21.

Is this a safe swap?

Diameter difference −2.13%: within the ±3% guideline

By overall diameter alone, 275/50R21 falls inside the ±3% range commonly used as a guideline when replacing 265/60R20. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 265/60R20 (32.52 in) vs 275/50R21 (31.83 in)265/60R2032.52 in × 10.43 in275/50R2131.83 in × 10.83 in
Side profile and tread width, drawn to the same scale.
265/60R20 vs 275/50R21 differences
Measurement265/60R20275/50R21Difference% diff
Overall diameter32.52 in (826.0 mm)31.83 in (808.4 mm)−0.69 in (−17.6 mm)−2.13%
Sidewall height6.26 in (159.0 mm)5.41 in (137.5 mm)−0.85 in (−21.5 mm)−13.52%
Section width10.43 in (265.0 mm)10.83 in (275.0 mm)+0.39 in (+10.0 mm)+3.77%
Circumference102.16 in (2,595.0 mm)99.99 in (2,539.7 mm)−2.18 in (−55.3 mm)−2.13%
Revolutions per mile620634+14+2.18%
True speed with the speedometer calibrated for 265/60R20
IndicatedActual on 265/60R20Actual on 275/50R21Difference
30 mph30.0 mph29.4 mph−0.6 mph
60 mph60.0 mph58.7 mph−1.3 mph
75 mph75.0 mph73.4 mph−1.6 mph

Ride-height change: 275/50R21 lowers the vehicle by 0.35 in (8.8 mm) at the axle (half the −17.6 mm diameter difference).

275/50R21 is 0.69 in shorter than 265/60R20 and 10 mm wider, a 2.13% difference in overall diameter.

With the speedometer calibrated for 265/60R20, an indicated 60 mph is actually 58.7 mph on 275/50R21, and revolutions per mile change from 620 to 634.

275/50R21 mounts on a 21-inch wheel, a plus-1 fitment from the 20-inch wheel of 265/60R20.

Size pages

Other comparisons with 265/60R20

Other comparisons with 275/50R21

Source: Calculated from standard tire geometry formulas. Verified . How these numbers are calculated.