TireSizesFinder

295/40R20 vs 295/35R21

295/35R21 is 0.16 in (4.1 mm) shorter than 295/40R20, a −0.55% diameter difference. With the speedometer set for 295/40R20, an indicated 60 mph is 59.7 mph on 295/35R21.

Is this a safe swap?

Diameter difference −0.55%: under 1%

By overall diameter alone, 295/35R21 is a near match for 295/40R20; the speedometer changes by less than 1%. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 295/40R20 (29.29 in) vs 295/35R21 (29.13 in)295/40R2029.29 in × 11.61 in295/35R2129.13 in × 11.61 in
Side profile and tread width, drawn to the same scale.
295/40R20 vs 295/35R21 differences
Measurement295/40R20295/35R21Difference% diff
Overall diameter29.29 in (744.0 mm)29.13 in (739.9 mm)−0.16 in (−4.1 mm)−0.55%
Sidewall height4.65 in (118.0 mm)4.06 in (103.3 mm)−0.58 in (−14.7 mm)−12.50%
Section width11.61 in (295.0 mm)11.61 in (295.0 mm)0.00 in (0.0 mm)0.00%
Circumference92.02 in (2,337.3 mm)91.51 in (2,324.5 mm)−0.51 in (−12.9 mm)−0.55%
Revolutions per mile689692+4+0.55%
True speed with the speedometer calibrated for 295/40R20
IndicatedActual on 295/40R20Actual on 295/35R21Difference
30 mph30.0 mph29.8 mph−0.2 mph
60 mph60.0 mph59.7 mph−0.3 mph
75 mph75.0 mph74.6 mph−0.4 mph

Ride-height change: 295/35R21 lowers the vehicle by 0.08 in (2.1 mm) at the axle (half the −4.1 mm diameter difference).

295/35R21 is 0.16 in shorter than 295/40R20 and the same width, a 0.55% difference in overall diameter.

With the speedometer calibrated for 295/40R20, an indicated 60 mph is actually 59.7 mph on 295/35R21, and revolutions per mile change from 689 to 692.

295/35R21 mounts on a 21-inch wheel, a plus-1 fitment from the 20-inch wheel of 295/40R20.

Size pages

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