tireheight.com255/45R18 in inches
A 255/45R18 tire is 27.0″ tall and 10.0″ wide, and fits a 18″ wheel. In inches it is written 27.0×10.0R18.
How tall 255/45R18 tires really are
Heights published by BFGoodrich, General, Michelin and Toyo for all 8 tires in this size. Their published revolutions per mile work out to 26.2–26.5″ under load (below).
Real 255/45R18 tires measure 27.00–27.40″, against 27.04″ from the size code. They run both taller and shorter than the size code.
- Michelin Pilot Sport All-Season 427.40″ +0.36″
- Michelin Primacy Tour A/S27.10″ +0.06″
- BFGoodrich g-Force COMP-2 A/S PLUS27.05″ +0.01″
- Michelin X-Ice Snow27.05″ +0.01″
- Toyo Extensa HP II27.05″ +0.01″
- Toyo Observe G3-Ice27.05″ +0.01″
- Toyo Proxes Sport A/S27.05″ +0.01″
- General G-MAX AS0727.00″ −0.04″
Published revs per mile (760–769) mean the tire rolls like a 26.2–26.5″ tire on the vehicle. Use this for speedometer calibration.
The lightest (Michelin Primacy Tour A/S, XL) is 5.8 lb lighter per corner than the heaviest (Toyo Proxes Sport A/S, XL).
8 tires in 255/45R18
Sort by the spec you care about.
| Load | Revs/mi | Source | |||||
|---|---|---|---|---|---|---|---|
| Michelin Primacy Tour A/STouring | XL · 103H | 27.10 | 24.9 | 9.0 | 1,929 | 769 | Spec page |
| General G-MAX AS07Performance | XL · 103W | 27.00 | 26.9 | 10.0 | 1,929 | 768 | Spec page |
| Michelin X-Ice SnowWinter | XL · 103H | 27.05 | 27.2 | 10.5 | 1,929 | 769 | Spec page |
| Toyo Extensa HP IIPerformance | XL · 103W | 27.05 | 27.8 | 9.7 | 1,929 | 768 | Spec page |
| Michelin Pilot Sport All-Season 4Performance | XL · 103Y | 27.40 | 28.2 | 10.0 | 1,929 | 760 | Spec page |
| BFGoodrich g-Force COMP-2 A/S PLUSPerformance | SL · 99W | 27.05 | 29.3 | 9.0 | 1,709 | 769 | Spec page |
| Toyo Observe G3-IceWinter | XL · 103T | 27.05 | 30.2 | 11.3 | 1,929 | 768 | Spec page |
| Toyo Proxes Sport A/SPerformance | XL · 103Y | 27.05 | 30.7 | 9.7 | 1,929 | 768 | Spec page |
Is 255/45R18 a 27-inch tire?
Yes. The size code works out to 27.04″, and the 8 tires here publish 27.00–27.40″, so people call it a 27.
All 27-inch tire sizes, on every wheel size.
Compare with nearby sizes
Differences in overall diameter, calculated from each size code.
How to read 255/45R18
A percentage, not a measurement: the sidewall is 45% as tall as the tire is wide, which is 114.8 mm or 4.52 inches.
Radial construction.
Mounts on a 18-inch wheel. Approved wheel widths run 8.0″ to 9.5″.
Each tire carries up to 1,929 lb (875 kg) at its maximum pressure.
Rated for up to 168 mph sustained.
Printed after the size. In this size the XL tires carry up to 1,929 lb each and the standard-load tires up to 1,709 lb, as published.
| Specification | Inches | Metric |
|---|---|---|
| Overall diameter | 27.04 | 687 mm |
| Section width | 10.04 | 255 mm |
| Sidewall height | 4.52 | 114.8 mm |
| Circumference | 84.9 | 2,157 mm |
| Revolutions per mile (calculated, unloaded) | 746.0 | 464 per km |
| Revolutions per mile (published by manufacturers) | 760–769 | 472–478 per km |
| Approved wheel width | 8.0–9.5 | 203–241 mm |
Speedometer error after switching to 255/45R18
Questions about 255/45R18
What is 255/45R18 in inches?
27.04 inches tall, 10.04 inches wide, on a 18-inch wheel. Written in inches, that is roughly 27.0×10.0R18.
How much does a 255/45R18 tire weigh?
Between 24.9 lb and 30.7 lb for the 8 tires listed here. The lightest is the Michelin Primacy Tour A/S (XL); the heaviest is the Toyo Proxes Sport A/S (XL).
What wheel width do I need for 255/45R18?
Manufacturers approve 8.0–9.5″ wide wheels for this size.
How many revolutions per mile does a 255/45R18 make?
Published figures run 760–769 revolutions per mile. The calculated figure is 746.0, but manufacturers measure the tire under load, where it rolls on a smaller radius.
How much taller is 255/45R18 than 285/40R18?
0.06 inches taller on paper (27.04″ vs 26.98″), which raises the axle about 0.03″. Your speedometer will read about 0.2% slow.