tireheight.com285/45R21 in inches
A 285/45R21 tire is 31.1″ tall and 11.2″ wide, and fits a 21″ wheel. In inches it is written 31.1×11.2R21.
How tall 285/45R21 tires really are
Heights published by Michelin and Toyo for all 8 tires in this size. Their published revolutions per mile work out to 30.1″ under load (below).
Real 285/45R21 tires measure 31.00–31.10″, against 31.10″ from the size code. They run both taller and shorter than the size code.
Published revs per mile (669–670) mean the tire rolls like a 30.1″ tire on the vehicle. Use this for speedometer calibration.
The lightest (Michelin Pilot Sport All-Season 4, XL) is 6.2 lb lighter per corner than the heaviest (Michelin Pilot Sport 4 SUV, XL).
8 tires in 285/45R21
Sort by the spec you care about.
| Load | Revs/mi | Source | |||||
|---|---|---|---|---|---|---|---|
| Michelin Pilot Sport All-Season 4Performance | XL · 113Y | 31.10 | 33.1 | 10.0 | 2,535 | 670 | Spec page |
| Michelin CrossClimate2All-season | XL · 113V | 31.06 | 33.6 | 10.0 | – | 670 | Spec page |
| Michelin Pilot Alpin 5Winter | XL · 113V | 31.06 | 36.6 | 10.5 | 2,535 | 670 | Spec page |
| Michelin Pilot Sport 4 SUVPerformance | XL · 113(Y) | 31.10 | 36.7 | 9.0 | 2,535 | 670 | Spec page |
| Michelin X-Ice SnowWinter | XL · 113H | 31.06 | 37.1 | 10.5 | 2,535 | 670 | Spec page |
| Toyo Proxes Sport 2Performance | XL · 113(Y) | 31.00 | 37.3 | 9.2 | 2,535 | 669 | Spec page |
| Michelin Pilot Sport 4 SUVPerformance | XL · 113Y | 31.10 | 37.5 | 9.5 | 2,535 | 670 | Spec page |
| Michelin Pilot Sport 4 SUVPerformance | XL · 113Y | 31.10 | 39.3 | 9.0 | 2,535 | 670 | Spec page |
Is 285/45R21 a 31-inch tire?
Yes. The size code works out to 31.10″, and the 8 tires here publish 31.00–31.10″, 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.
How to read 285/45R21
A percentage, not a measurement: the sidewall is 45% as tall as the tire is wide, which is 128.3 mm or 5.05 inches.
Radial construction.
Mounts on a 21-inch wheel. Approved wheel widths run 9.0″ to 10.5″.
Each tire carries up to 2,535 lb (1,150 kg) at its maximum pressure.
Rated for up to 186 mph sustained.
Printed after the size.
| Specification | Inches | Metric |
|---|---|---|
| Overall diameter | 31.10 | 790 mm |
| Section width | 11.22 | 285 mm |
| Sidewall height | 5.05 | 128.3 mm |
| Circumference | 97.7 | 2,482 mm |
| Revolutions per mile (calculated, unloaded) | 648.5 | 403 per km |
| Revolutions per mile (published by manufacturers) | 669–670 | 416 per km |
| Approved wheel width | 9.0–10.5 | 229–267 mm |
Speedometer error after switching to 285/45R21
Questions about 285/45R21
What is 285/45R21 in inches?
31.10 inches tall, 11.22 inches wide, on a 21-inch wheel. Written in inches, that is roughly 31.1×11.2R21.
How much does a 285/45R21 tire weigh?
Between 33.1 lb and 39.3 lb for the 8 tires listed here. The lightest is the Michelin Pilot Sport All-Season 4 (XL); the heaviest is the Michelin Pilot Sport 4 SUV (XL).
What wheel width do I need for 285/45R21?
Manufacturers approve 9.0–10.5″ wide wheels for this size.
How many revolutions per mile does a 285/45R21 make?
Published figures run 669–670 revolutions per mile. The calculated figure is 648.5, but manufacturers measure the tire under load, where it rolls on a smaller radius.
How much taller is 285/45R21 than 255/50R21?
0.06 inches taller on paper (31.10″ vs 31.04″), which raises the axle about 0.03″. Your speedometer will read about 0.2% slow.