Tire Conversions and Load Ratings - Nearest Inch Tire Width - Metric Tire Width - Load Index

Oct 13, 2026

Tire Conversions and Load Ratings provides cross-reference tables for matching tire widths and sizes, including nearest-inch and metric tire width equivalents and corresponding load values. It also maps conventional tire designations to metric formats, defines speed symbols with their maximum permitted speed in km/h and mph, and explains equivalent load designations using ply rating and load index. Additional sections cover star ratings and agricultural tread classifications, plus an international load index lookup in kg and lb.

LanguageEnglish

CategoryGeneral

FormatPDF

Pages2

Reading Time1 min

AccessFree to download

Tire conversions

Nearest inch tire width - metric tire width

Nearest conventional tire size - metric tire size

Speed symbols (km/h and mph)

Equivalent load designations

Star ratings and agricultural tread markings

International load index (kg and lb)

[1.800.USA-BEAR | www.titan-intl.](1.800.USA-BEAR | www.titan-intl.com)[com](1.800.USA-BEAR | www.titan-intl.com) TIRE CONVERSIONS AND LOAD RATINGS NEAREST INCH TIRE WIDTH METRIC TIRE WIDTH 9.0 230 | 9.5 | 240 | | --- | --- | | 10.0 | 250 | | 10.0 | 260 | | 11.2 | 290 | | 12.4 | 320 | | 13.6 | 340 | | 14.9 | 380 | | 15.5 | 400 | | 16.9 | 420 | | 16.9 | 430 | | 16.9 | 440 | | 18.4 | 480 | | 20.8 | 520 | | 20.8 | 525 | | 23.1 | 580 | | 23.1 | 600 | | 24.5 | 620 | | 24.5 | 650 | | 28.0 | 710 | | 30.5 | 800 | | 35.5 | 900 | | 43.3 | 1100 | NEAREST CONVENTIONAL TIRE SIZE METRIC TIRE SIZE 14.9R28 380/85R28 | 14.9R30 | 380/85R30 | | --- | --- | | 14.9R34 | 380/85R34 | | 14.9R46 | 380/90R46 | | 16.9R28 | 420/85R28 | | 16.9R30 | 420/90R30 | | 18.4R34 | 480/85R34 | | 18.4R38 | 480/80R38 | | 18.4R42 | 480/80R42 | | 18.4R46 | 480/80R46 | | 20.8R38 | 520/85R38 | | 20.8R42 | 520/85R42 | SPEED SPEED SPEED SYMBOLS (km/h) (mph) A1 5 2.5 | A2 | 10 | 5 | | --- | --- | --- | | A3 | 15 | 10 | | A4 | 20 | 12.5 | | A5 | 25 | 15 | | A6 | 30 | 20 | | A7 | 35 | 22.5 | | A8 | 40 | 25 | | B | 50 | 30 | | C | 60 | 35 | | D | 65 | 40 | | E | 70 | 43 | | F | 80 | 50 | | G | 90 | 55 | | SPEED SYMBOLS | | --- | | The speed symbol determines the maximum speed allowed for the rated loads of the tire. From the table above, A8 means the maximum speed allowed for the rated load of the tire is 40 km/hor 25 mph. | EQUIVALENT LOAD DESIGNATIONS SIZE SYMBOL PLY RATING LOAD INDEX 13.6R28 HHH 8PR 126 A8/B | 14.9R28 | HHH | 10PR | 133 A8/B | | --- | --- | --- | --- | | 14.9R30 | HHH | 10PR | 134 A8/B | | 14.9R34 | HHH | 10PR | 136 A8/B | | 14.9R46 | HHH | 10PR | 142 A8/B | | 16.9R24 | HH | 8 & 10PR | 134 A8/B | | 16.9R26 | HH | 8 & 10PR | 135 A8/B | | 16.9R28 | HH | 8 & 10PR | 136 A8/B | | 16.9R30 | HH | 8 & 10PR | 137 A8/B | | 16.9R38 | H | 8PR | 141 A8/B | | 18.4R26 | HH | 8 & 10PR | 140 A8/B | | 18.4R34 | H | 6 & 8PR | 139 A8/B | | 18.4R38 | H | 6 & 8PR | 141 A8/B | | 18.4R38 | HH | 10PR | 146 A8/B | | 18.4R42 | HH | 10PR | 148 A8/B | | 18.4R46 | HHH | 12PR | 155 A8/B | | 20.8R34 | H | 8PR | 145 A8/B | | 20.8R38 | H | 8PR | 147 A8/B | | 20.8R38 | HH | 10PR | 153 A8/B | | 20.8R42 | HH | 10PR | 155 A8/B | | 24.5R32 | H | 10PR | 154 A8/B | STAR RATINGS All conventional sized radials for agricultural applications are marked with the star ratings. This specifies the maximum load rating for the designated inflation pressure. | H | Max load @ 18 psi | | --- | --- | | HH | Max load @ 24 psi | HHH Max load @ 30 psi F-1 Agricultural single-rib tread | F-2 | Agricultural multi-rib tread | | --- | --- | | F-2D | Agricultural dual rib | | F-2M | Agricultural multi-rib tread | | F-3 | Industrial multi-rib tread | | R-1 | Drive wheel—Regular tread (dry, well-drained soil) | | R-1W | Drive wheel—Wet traction tread (wet soil); generally 25% deeper tread than R-1 | | R-2 | Drive wheel—Rice and cane (wet, muck) | | R-3 | Drive wheel—“Button design”(orchards, golf courses, grass cutting, light industrial) | | R-4 | Drive wheel—Industrial use | Titan Tire Corporation • 2345 East Market Street • Des Moines, Iowa 50317 [1.800.USA-BEAR | www.titan-intl.](1.800.USA-BEAR | www.titan-intl.com)[com](1.800.USA-BEAR | www.titan-intl.com) INTERNATIONAL LOAD INDEX (Not applicable to passenger car, light truck or truck-bus tires) | LOAD INDEX | KG | LB | | LOAD INDEX | KG | LB | | --- | --- | --- | --- | --- | --- | --- | | LOAD INDEX | KG | LB | | --- | --- | --- | 40 140 310 | 41 | 145 | 320 | | --- | --- | --- | | 42 | 150 | 330 | | 43 | 155 | 340 | | 44 | 160 | 355 | | 45 | 165 | 366 | | 46 | 170 | 375 | | 47 | 175 | 385 | | 48 | 180 | 395 | | 49 | 185 | 410 | | 50 | 190 | 420 | | 51 | 195 | 430 | | 52 | 200 | 440 | | 53 | 206 | 455 | | 54 | 212 | 465 | | 55 | 218 | 480 | | 56 | 224 | 495 | | 57 | 230 | 505 | | 58 | 236 | 520 | | 59 | 243 | 535 | | 60 | 250 | 550 | | 61 | 257 | 565 | | 62 | 265 | 585 | | 63 | 272 | 600 |

FAQs

How do speed symbols relate to maximum tire speed?

The speed symbol indicates the maximum speed allowed for the tire’s rated loads. For example, A8 corresponds to 40 km/h (25 mph) for the rated load.

What is included in the equivalent load designations section?

The document lists size symbols, ply ratings, and load index values. These combinations support matching tire size to an equivalent load designation.

What do star ratings specify for conventional agricultural radial tires?

Star ratings identify the maximum load rating for the designated inflation pressure. The document provides max load values tied to specific psi levels.

Oct 13, 2026

Upload by Aria Callaghan