tireheight.com

255/40R20 in inches

A 255/40R20 tire is 28.0″ tall and 10.0″ wide, and fits a 20″ wheel. In inches it is written 28.0×10.0R20.

Diameter28.03″
Width10.04″
Sidewall4.02″
255/40R20 drawn to scale: 28.03 inch diameter, 4.02 inch sidewall, 20 inch wheel, 10.04 inch tread width20″ wheel4.02″28.03″ overall10.04″ wideSide view
Drawn to scale. Nominal dimensions calculated from the size code.
Manufacturer data

How tall 255/40R20 tires really are

Heights published by BFGoodrich, Michelin and Toyo for all 22 tires in this size. Their published revolutions per mile work out to 27.2″ under load (below).

Real 255/40R20 tires measure 28.00–28.40″, against 28.03″ from the size code. They run both taller and shorter than the size code.

  1. Michelin Pilot Sport All-Season 428.40″ +0.37″
  2. Toyo Proxes Sport28.03″ −0.00″
  3. Toyo Proxes Sport A/S28.03″ −0.00″
  4. BFGoodrich g-Force Phenom T/A28.03″ −0.00″
  5. Michelin CrossClimate228.03″ −0.00″
  6. Michelin Pilot Alpin 5 · 228.03″ −0.00″
  7. Michelin Pilot Alpin PA4 · 228.03″ −0.00″
  8. Michelin X-Ice Snow28.03″ −0.00″
  9. Michelin e.Primacy All Season28.00″ −0.03″
  10. Michelin Pilot Sport 328.00″ −0.03″
  11. Michelin Pilot Sport 4 · 228.00″ −0.03″
  12. Michelin Pilot Sport 4 S · 228.00″ −0.03″
  13. Michelin Pilot Sport 5 · 228.00″ −0.03″
  14. Michelin Pilot Sport Cup 2 Connect28.00″ −0.03″
  15. Michelin Pilot Super Sport28.00″ −0.03″
  16. Toyo Celsius Sport28.00″ −0.03″
  17. Toyo Proxes Sport 228.00″ −0.03″
Each bar runs from the size code's 28.03″ (the orange line) to the model's published height. The track spans 1.0″. Where a model comes in several load ranges, the darker part shows its range of heights; the number after the name is how many versions it comes in.
Height under load27.2″

Published revs per mile (741–742) mean the tire rolls like a 27.2″ tire on the vehicle. Use this for speedometer calibration.

Weight spread25.3–32.1 lb

The lightest (Michelin Pilot Sport Cup 2 Connect, XL) is 6.8 lb lighter per corner than the heaviest (Michelin Pilot Sport 4, XL).

22 tires in 255/40R20

Sort by the spec you care about.

LoadRevs/miSource
Michelin Pilot Sport Cup 2 ConnectPerformanceXL · 101(Y)28.0025.37.21,819742Spec page
Michelin Pilot Sport 4 SPerformanceXL · 101(Y)28.0026.59.51,819742Spec page
Michelin Pilot Sport 5PerformanceXL · 101Y28.0026.99.01,819742Spec page
Michelin Pilot Alpin 5WinterXL · 101W28.0327.19.51,819742Spec page
Michelin Pilot Super SportPerformanceXL · 101(Y)28.0027.39.01,819742Spec page
Toyo Proxes SportPerformanceXL · 101(Y)28.0327.69.41,819741Spec page
Michelin Pilot Sport 5PerformanceXL · 101Y28.0027.69.01,819742Spec page
Toyo Proxes Sport 2PerformanceXL · 101(Y)28.0027.69.21,819741Spec page
Michelin e.Primacy All SeasonTouringXL · 101W28.0028.18.51,819742Spec page
Michelin Pilot Alpin 5WinterXL · 101V28.0328.29.51,819742Spec page
Michelin Pilot Alpin PA4WinterXL · 101V28.0328.210.51,819742Spec page
Michelin Pilot Sport 4PerformanceXL · 101Y28.0028.29.51,819742Spec page
Michelin Pilot Sport All-Season 4PerformanceXL · 101Y28.4028.310.01,819742Spec page
Michelin Pilot Alpin PA4WinterXL · 101V28.0328.410.51,819742Spec page
Michelin Pilot Sport 4 SPerformanceXL · 101(Y)28.0028.49.51,819742Spec page
Michelin X-Ice SnowWinterXL · 101H28.0328.410.51,819742Spec page
Michelin CrossClimate2All-seasonXL · 101W28.0329.310.01,819742Spec page
Michelin Pilot Sport 3PerformanceXL · 101(Y)28.0029.39.01,819742Spec page
BFGoodrich g-Force Phenom T/APerformanceXL · 101Y28.0329.68.51,819742Spec page
Toyo Proxes Sport A/SPerformanceXL · 101Y28.0330.39.61,819741Spec page
Toyo Celsius SportPerformanceSL · 101Y28.0030.610.01,819741Spec page
Michelin Pilot Sport 4PerformanceXL · 101Y28.0032.19.51,819742Spec page

Is 255/40R20 a 28-inch tire?

≈28″

Yes. The size code works out to 28.03″, and the 22 tires here publish 28.00–28.40″, so people call it a 28.

All 28-inch tire sizes, on every wheel size.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

SizeDiameter ″vs 255/40R20Difference
215/45R2027.62-0.41″-1.5%
325/30R2027.68-0.35″-1.3%
245/40R2027.72-0.31″-1.1%
285/35R2027.85-0.18″-0.6%
335/30R2027.91-0.12″-0.4%
295/35R2028.13+0.10″+0.4%
345/30R2028.15+0.12″+0.4%
235/45R2028.33+0.30″+1.1%
265/40R2028.35+0.31″+1.1%
305/35R2028.41+0.37″+1.3%

How to read 255/40R20

How to read any tire size

255/40R20 101Y as printed on the tire sidewall, with each part numbered255/40R20 101Y123456
How 255/40R20 101Y is printed on the sidewall. It's the most common code among the 22 tires here (7 of them); tires in this size come in other load and speed ratings too.
1255Section width

255 mm across the widest point, or 10.04 inches. Every 255 size

240Aspect ratio

A percentage, not a measurement: the sidewall is 40% as tall as the tire is wide, which is 102.0 mm or 4.02 inches.

3RConstruction

Radial construction.

420Wheel diameter

Mounts on a 20-inch wheel. Approved wheel widths run 8.5″ to 10.0″.

5101Load index

Each tire carries up to 1,819 lb (825 kg) at its maximum pressure.

6YSpeed rating

Rated for up to 186 mph sustained.

XLExtra load

Printed after the size. In this size the XL tires carry up to 1,819 lb each and the standard-load tires up to 1,819 lb, as published.

SpecificationInchesMetric
Overall diameter28.03712 mm
Section width10.04255 mm
Sidewall height4.02102.0 mm
Circumference88.12,237 mm
Revolutions per mile (calculated, unloaded)719.5447 per km
Revolutions per mile (published by manufacturers)741–742460–461 per km
Approved wheel width8.5–10.0216–254 mm

Speedometer error after switching to 255/40R20

Your actual speed– mph

Questions about 255/40R20

What is 255/40R20 in inches?

28.03 inches tall, 10.04 inches wide, on a 20-inch wheel. Written in inches, that is roughly 28.0×10.0R20.

How much does a 255/40R20 tire weigh?

Between 25.3 lb and 32.1 lb for the 22 tires listed here. The lightest is the Michelin Pilot Sport Cup 2 Connect (XL); the heaviest is the Michelin Pilot Sport 4 (XL).

What wheel width do I need for 255/40R20?

Manufacturers approve 8.5–10.0″ wide wheels for this size.

How many revolutions per mile does a 255/40R20 make?

Published figures run 741–742 revolutions per mile. The calculated figure is 719.5, but manufacturers measure the tire under load, where it rolls on a smaller radius.

How much taller is 255/40R20 than 335/30R20?

0.12 inches taller on paper (28.03″ vs 27.91″), which raises the axle about 0.06″. Your speedometer will read about 0.4% slow.