CarSpecsHQ

265/40R20 tire size

265/40R20 is a metric size: 28.3" tall, 10.4" wide, on a 20" rim — about a 28.5x10.50R20. The sidewall is 4.2" and the tire turns 711 times per mile.

Diameter 28.3" sidewall 4.17" 20" rim width 265 mm (10.4")
265/40R20: 265 mm wide, sidewall 40% of the width (4.17"), on a 20" rim → 28.35" tall.

265/40R20 specs

Overall diameter (height)28.35" · 720 mm
Section width10.43" · 265 mm
Sidewall height4.17" · 106 mm (40% of width)
Rim diameter20"
Circumference89.05" · 2.262 m
Revolutions per mile711 (442 per km)
Inch (flotation) equivalent28.5x10.50R20

Equivalent sizes on a 20" rim

Sizes within ±5% of the overall diameter. Green rows are inside the usual ±3% limit for keeping the speedometer, ABS and gearing right; red rows are bigger changes that need clearance checks.

SizeDiameterDifferenceWidthSpeedo at 60
245/45R20 common28.68"+1.18%-20 mm60.7 mphcompare →
255/45R20 common29.04"+2.43%-10 mm61.5 mphcompare →
275/40R20 common28.66"+1.11%+10 mm60.7 mphcompare →
245/40R20 common27.72"-2.22%-20 mm58.7 mphcompare →
245/50R20 common29.65"+4.58%-20 mm62.8 mphcompare →
275/45R20 common29.74"+4.93%+10 mm63.0 mphcompare →
255/35R20 common27.03"-4.65%-10 mm57.2 mphcompare →
255/40R20 common28.03"-1.11%-10 mm59.3 mphcompare →
275/35R20 common27.58"-2.71%+10 mm58.4 mphcompare →
265/45R20 common29.39"+3.68%0 mm62.2 mphcompare →
285/35R20 common27.85"-1.74%+20 mm59.0 mphcompare →
315/35R20 common28.68"+1.18%+50 mm60.7 mphcompare →
265/35R20 common27.30"-3.68%0 mm57.8 mphcompare →
295/30R2026.97"-4.86%+30 mm57.1 mphcompare →
305/30R2027.20"-4.03%+40 mm57.6 mphcompare →
295/40R2029.29"+3.33%+30 mm62.0 mphcompare →
295/35R2028.13"-0.76%+30 mm59.5 mphcompare →
305/35R2028.41"+0.21%+40 mm60.1 mphcompare →
285/40R2028.98"+2.22%+20 mm61.3 mphcompare →
235/50R2029.25"+3.19%-30 mm61.9 mphcompare →
235/45R2028.33"-0.07%-30 mm60.0 mphcompare →
305/40R2029.61"+4.44%+40 mm62.7 mphcompare →
315/30R2027.44"-3.19%+50 mm58.1 mphcompare →
235/40R2027.40"-3.33%-30 mm58.0 mphcalculate →
335/30R2027.91"-1.53%+70 mm59.1 mphcalculate →
325/30R2027.68"-2.36%+60 mm58.6 mphcalculate →
345/30R2028.15"-0.69%+80 mm59.6 mphcalculate →
215/45R2027.62"-2.57%-50 mm58.5 mphcalculate →
325/35R2028.96"+2.15%+60 mm61.3 mphcalculate →
195/50R2027.68"-2.36%-70 mm58.6 mphcalculate →
225/40R2027.09"-4.44%-40 mm57.3 mphcalculate →
29x15.00R2029.00"+2.31%+116 mm61.4 mphcalculate →
29x18.00R2029.00"+2.31%+192 mm61.4 mphcalculate →
175/55R2027.58"-2.71%-90 mm58.4 mphcalculate →
145/65R2027.42"-3.26%-120 mm58.0 mphcalculate →
155/60R2027.32"-3.61%-110 mm57.8 mphcalculate →
195/55R2028.44"+0.35%-70 mm60.2 mphcalculate →
225/45R2027.97"-1.32%-40 mm59.2 mphcalculate →
155/65R2027.93"-1.46%-110 mm59.1 mphcalculate →
165/60R2027.80"-1.94%-100 mm58.8 mphcalculate →
175/70R2029.65"+4.58%-90 mm62.8 mphcalculate →

Plus / minus sizing: 19" and 21" rims

Same overall height on a different rim. Check wheel width and clearance before switching.

SizeDiameterDifferenceWidthSpeedo at 60
235/50R19 common28.25"-0.33%-30 mm59.8 mphcompare →
275/35R21 common28.58"+0.82%+10 mm60.5 mphcompare →
265/35R2128.30"-0.15%0 mm59.9 mphcompare →
315/30R2128.44"+0.33%+50 mm60.2 mphcompare →
305/30R2128.20"-0.50%+40 mm59.7 mphcompare →
295/40R1928.29"-0.19%+30 mm59.9 mphcompare →
265/45R1928.39"+0.15%0 mm60.1 mphcalculate →
345/35R1928.51"+0.57%+80 mm60.3 mphcalculate →
145/80R1928.13"-0.75%-120 mm59.5 mphcalculate →

Try another size against 265/40R20

Questions

What size is 265/40R20 in inches?

265/40R20 is about 28.3" tall and 10.4" wide on a 20-inch rim — roughly a 28.5x10.50R20 in inch sizing.

What does 265/40R20 mean?

265 mm section width, sidewall 40% of the width (4.17"), radial construction, 20-inch rim.

What tire sizes are equivalent to 265/40R20?

On the same 20" rim, within 3% of the diameter: 235/45R20 (-0.07%), 305/35R20 (+0.21%), 195/55R20 (+0.35%), 345/30R20 (-0.69%), 295/35R20 (-0.76%), 255/40R20 (-1.11%).

How many revolutions per mile does a 265/40R20 tire make?

About 711 revolutions per mile (circumference 89.1").

How these numbers are computed

Diameter = rim + 2 × sidewall, sidewall = width × aspect ÷ 100, circumference = π × diameter, revolutions per mile = 63,360 ÷ circumference. Real tires differ by brand by a few tenths of an inch. Last reviewed October 14, 2026.