tireheight.com

275/45R21 in inches

A 275/45R21 tire is 30.7″ tall and 10.8″ wide, and fits a 21″ wheel. In inches it is written 30.7×10.8R21.

Diameter30.74″
Width10.83″
Sidewall4.87″
275/45R21 drawn to scale: 30.74 inch diameter, 4.87 inch sidewall, 21 inch wheel, 10.83 inch tread width21″ wheel4.87″30.74″ overall10.83″ wideSide view
Drawn to scale. Nominal dimensions calculated from the size code.
Manufacturer data

How tall 275/45R21 tires really are

Heights published by BFGoodrich, General, Michelin and Toyo for all 16 tires in this size. Their published revolutions per mile work out to 29.8–30.0″ under load (below).

Real 275/45R21 tires measure 30.70–30.90″, against 30.74″ from the size code. They run both taller and shorter than the size code.

  1. Michelin Pilot Sport All-Season 4 · 230.80–30.90″ +0.16″
  2. Michelin Latitude Sport 3 · 230.80″ +0.06″
  3. Michelin Pilot Sport 4 SUV · 230.80″ +0.06″
  4. Michelin Primacy Tour A/S30.80″ +0.06″
  5. Toyo Proxes Sport 230.80″ +0.06″
  6. BFGoodrich Advantage Control30.75″ +0.01″
  7. Michelin Pilot Alpin 530.75″ +0.01″
  8. Michelin X-Ice Snow30.75″ +0.01″
  9. Michelin X-Ice Snow+30.75″ +0.01″
  10. Toyo Celsius Sport30.75″ +0.00″
  11. Toyo OPEN COUNTRY Q/T30.75″ +0.00″
  12. General G-MAX AS0730.70″ −0.04″
  13. Michelin CrossClimate230.70″ −0.04″
Each bar runs from the size code's 30.74″ (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 load29.8–30.0″

Published revs per mile (673–676) mean the tire rolls like a 29.8–30.0″ tire on the vehicle. Use this for speedometer calibration.

Weight spread32.0–37.5 lb

The lightest (Michelin Pilot Sport All-Season 4, XL) is 5.5 lb lighter per corner than the heaviest (BFGoodrich Advantage Control, XL).

16 tires in 275/45R21

Sort by the spec you care about.

LoadRevs/miSource
Michelin Pilot Sport All-Season 4PerformanceXL · 110Y30.9032.010.02,337673Spec page
Michelin Primacy Tour A/STouringSL · 107H30.8032.88.52,149676Spec page
Michelin CrossClimate2All-seasonXL · 110V30.7033.610.02,337676Spec page
Michelin Pilot Sport 4 SUVPerformanceXL · 110Y30.8033.69.52,337676Spec page
Michelin Pilot Sport All-Season 4PerformanceXL · 110V30.8033.79.02,337676Spec page
General G-MAX AS07PerformanceXL · 110W30.7034.410.02,337676Spec page
Toyo Proxes Sport 2PerformanceXL · 110Y30.8034.89.22,337676Spec page
Michelin X-Ice Snow+WinterXL · 110H30.7535.010.52,337676Spec page
Michelin Pilot Sport 4 SUVPerformanceXL · 110Y30.8035.39.52,337676Spec page
Michelin X-Ice SnowWinterXL · 110T30.7535.310.52,337676Spec page
Michelin Pilot Alpin 5WinterXL · 110V30.7536.09.52,337676Spec page
Toyo Celsius SportPerformanceXL · 110Y30.7536.19.72,337676Spec page
Toyo OPEN COUNTRY Q/TAll-seasonXL · 110W30.7536.310.62,337676Spec page
Michelin Latitude Sport 3PerformanceSL · 107Y30.8036.48.52,149676Spec page
Michelin Latitude Sport 3PerformanceSL · 107Y30.8036.58.52,149676Spec page
BFGoodrich Advantage ControlAll-seasonXL · 110W30.7537.510.52,337676Spec page

Is 275/45R21 a 31-inch tire?

≈31″

Yes. The size code works out to 30.74″, and the 16 tires here publish 30.70–30.90″, so people call it a 31.

All 31-inch tire sizes, on every wheel size.

Compare with nearby sizes

Differences in overall diameter, calculated from each size code.

SizeDiameter ″vs 275/45R21Difference
285/40R2129.98-0.77″-2.5%
255/45R2130.04-0.71″-2.3%
235/50R2130.25-0.49″-1.6%
295/40R2130.29-0.45″-1.5%
265/45R2130.39-0.35″-1.2%
305/40R2130.61-0.14″-0.4%
305/45R2030.81+0.06″+0.2%
315/40R2130.92+0.18″+0.6%
255/50R2131.04+0.30″+1.0%
285/45R2131.10+0.35″+1.2%

How to read 275/45R21

How to read any tire size

275/45R21 110Y as printed on the tire sidewall, with each part numbered275/45R21 110Y123456
How 275/45R21 110Y is printed on the sidewall. It's the most common code among the 16 tires here (5 of them); tires in this size come in other load and speed ratings too.
1275Section width

275 mm across the widest point, or 10.83 inches. Every 275 size

245Aspect ratio

A percentage, not a measurement: the sidewall is 45% as tall as the tire is wide, which is 123.8 mm or 4.87 inches.

3RConstruction

Radial construction.

421Wheel diameter

Mounts on a 21-inch wheel. Approved wheel widths run 7.5″ to 10.5″.

5110Load index

Each tire carries up to 2,337 lb (1,060 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 2,337 lb each and the standard-load tires up to 2,149 lb, as published.

SpecificationInchesMetric
Overall diameter30.74781 mm
Section width10.83275 mm
Sidewall height4.87123.8 mm
Circumference96.62,453 mm
Revolutions per mile (calculated, unloaded)656.0408 per km
Revolutions per mile (published by manufacturers)673–676418–420 per km
Approved wheel width7.5–10.5191–267 mm

Speedometer error after switching to 275/45R21

Your actual speed– mph

Questions about 275/45R21

What is 275/45R21 in inches?

30.74 inches tall, 10.83 inches wide, on a 21-inch wheel. Written in inches, that is roughly 30.7×10.8R21.

How much does a 275/45R21 tire weigh?

Between 32.0 lb and 37.5 lb for the 16 tires listed here. The lightest is the Michelin Pilot Sport All-Season 4 (XL); the heaviest is the BFGoodrich Advantage Control (XL).

What wheel width do I need for 275/45R21?

Manufacturers approve 7.5–10.5″ wide wheels for this size.

How many revolutions per mile does a 275/45R21 make?

Published figures run 673–676 revolutions per mile. The calculated figure is 656.0, but manufacturers measure the tire under load, where it rolls on a smaller radius.

How much taller is 275/45R21 than 305/40R21?

0.14 inches taller on paper (30.74″ vs 30.61″), which raises the axle about 0.07″. Your speedometer will read about 0.5% slow.