TireSizesFinder

275/40R21 vs 295/40R21

295/40R21 is 0.63 in (16.0 mm) taller than 275/40R21, a +2.12% diameter difference. With the speedometer set for 275/40R21, an indicated 60 mph is 61.3 mph on 295/40R21.

Is this a safe swap?

Diameter difference +2.12%: within the ±3% guideline

By overall diameter alone, 295/40R21 falls inside the ±3% range commonly used as a guideline when replacing 275/40R21. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 275/40R21 (29.66 in) vs 295/40R21 (30.29 in)275/40R2129.66 in × 10.83 in295/40R2130.29 in × 11.61 in
Side profile and tread width, drawn to the same scale.
275/40R21 vs 295/40R21 differences
Measurement275/40R21295/40R21Difference% diff
Overall diameter29.66 in (753.4 mm)30.29 in (769.4 mm)+0.63 in (+16.0 mm)+2.12%
Sidewall height4.33 in (110.0 mm)4.65 in (118.0 mm)+0.31 in (+8.0 mm)+7.27%
Section width10.83 in (275.0 mm)11.61 in (295.0 mm)+0.79 in (+20.0 mm)+7.27%
Circumference93.18 in (2,366.9 mm)95.16 in (2,417.1 mm)+1.98 in (+50.3 mm)+2.12%
Revolutions per mile680666−14−2.08%
True speed with the speedometer calibrated for 275/40R21
IndicatedActual on 275/40R21Actual on 295/40R21Difference
30 mph30.0 mph30.6 mph+0.6 mph
60 mph60.0 mph61.3 mph+1.3 mph
75 mph75.0 mph76.6 mph+1.6 mph

Ride-height change: 295/40R21 raises the vehicle by 0.31 in (8.0 mm) at the axle (half the +16.0 mm diameter difference).

295/40R21 is 0.63 in taller than 275/40R21 and 20 mm wider, a 2.12% difference in overall diameter.

With the speedometer calibrated for 275/40R21, an indicated 60 mph is actually 61.3 mph on 295/40R21, and revolutions per mile change from 680 to 666.

Both sizes mount on 21-inch wheels.

Size pages

Other comparisons with 275/40R21

Other comparisons with 295/40R21

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