Enter a size below (e.g. 265/70R17 or 35x12.50R17) to jump to its geometry and verified fit list, or browse the 49 sizes this library currently has a built, index-worthy page for. Each listed size has US search demand and at least 3 tires in this library that the maker's own spec page confirms are sold in it. Sizes with fewer verified fits stay off this index; the tire finder filters the full library by size.
All Indexable Sizes
| Size | Overall diameter | Verified fits | Monthly search volume |
|---|---|---|---|
| 265/70R17 | 31.6in | 54 | 40,500 |
| 275/60R20 | 33in | 43 | 33,100 |
| 275/55R20 | 31.9in | 44 | 33,100 |
| 285/70R17 | 32.7in | 53 | 27,100 |
| 265/75R16 | 31.6in | 44 | 18,100 |
| 235/75R15 | 28.9in | 20 | 18,100 |
| 285/75R16 | 32.8in | 37 | 14,800 |
| 275/65R18 | 32.1in | 47 | 14,800 |
| 275/70R18 | 33.2in | 49 | 14,800 |
| 245/75R16 | 30.5in | 35 | 12,100 |
| 265/70R16 | 30.6in | 32 | 12,100 |
| 35X12.50R20 | 35in | 36 | 12,100 |
| 265/65R18 | 31.6in | 33 | 9,900 |
| 33X12.50R20 | 33in | 29 | 9,900 |
| 315/70R17 | 34.4in | 35 | 8,100 |
| 275/65R20 | 34.1in | 42 | 8,100 |
| 265/60R18 | 30.5in | 32 | 8,100 |
| 235/85R16 | 31.7in | 24 | 6,600 |
| 245/70R17 | 30.5in | 33 | 6,600 |
| 265/65R17 | 30.6in | 33 | 6,600 |
| 315/75R16 | 34.6in | 20 | 5,400 |
| 245/75R17 | 31.5in | 32 | 5,400 |
| 275/70R17 | 32.2in | 16 | 5,400 |
| 285/75R17 | 33.8in | 20 | 5,400 |
| 265/70R18 | 32.6in | 36 | 5,400 |
| 295/70R18 | 34.3in | 27 | 5,400 |
| 285/60R20 | 33.5in | 31 | 5,400 |
| 305/55R20 | 33.2in | 34 | 5,400 |
| 31X10.50R15 | 31in | 22 | 5,400 |
| 285/75R18 | 34.8in | 22 | 4,400 |
| 225/75R16 | 29.3in | 25 | 3,600 |
| 255/75R17 | 32.1in | 21 | 3,600 |
| 255/70R18 | 32.1in | 28 | 3,600 |
| 285/55R20 | 32.3in | 28 | 3,600 |
| 265/60R20 | 32.5in | 29 | 3,600 |
| 285/65R18 | 32.6in | 33 | 2,900 |
| 295/60R20 | 33.9in | 27 | 2,900 |
| 33X12.50R17 | 33in | 18 | 2,400 |
| 33X12.50R15 | 33in | 15 | 2,400 |
| 33X12.50R22 | 33in | 15 | 2,400 |
| 35X12.50R17 | 35in | 29 | 1,600 |
| 35X12.50R18 | 35in | 31 | 1,600 |
| 35X12.50R22 | 35in | 21 | 1,300 |
| 37X13.50R20 | 37in | 20 | 880 |
| 37X12.50R17 | 37in | 27 | 720 |
| 33X12.50R18 | 33in | 19 | 720 |
| 35X12.50R15 | 35in | 12 | 390 |
| 37X12.50R18 | 37in | 15 | 260 |
| 37X12.50R22 | 37in | 14 | 210 |
How to Read a Tire Size
A metric size such as LT265/70R17 has five parts, per NHTSA's sidewall guide:
- LT or P: LT marks a light-truck tire and P a passenger tire. Makers' charts list no-prefix metric sizes, such as 265/70R17, with passenger SL or XL load ratings.
- 265: section width in millimeters, sidewall edge to sidewall edge.
- 70: aspect ratio, the sidewall height as a percentage of the width.
- R: radial construction.
- 17: rim diameter in inches.
A flotation size such as 35x12.50R17LT states the dimensions directly: about 35in tall and 12.50in wide, on a 17in rim. NHTSA notes that the load index and speed rating that follow the size, such as 121/118Q, are not required by law, so not every tire shows them. On LT tires the two load indexes are the single-tire and dual-tire ratings.
The Math Behind the Diameter Column
Overall diameter for a metric size is the rim diameter plus two sidewalls. For 265/70R17, the sidewall is 265 × 0.70 = 185.5mm, or 7.3in, so the diameter is 17 + 2 × 7.3 = 31.6in. Revolutions per mile are 63,360 inches per mile divided by the circumference (π × diameter), about 638 for that size. Real tires come close to this nominal figure: Nitto lists its Ridge Grappler 265/70R17 at 31.65in inflated.
Flotation sizes usually measure under their nominal height. Nitto lists its 35x12.50R17LT at 34.76in, and Gladiator lists the X-Comp M/T 35x12.50R17LT at 34.5in. Michelin notes that actual tires may vary by about ±3% of section height and ±4% of section width from published design values. Section width also changes by about 0.2in for every 0.5in change in rim width. Check the maker's own published diameter before judging clearance.
Changing Size: Speedometer and Load
A taller tire turns fewer times per mile, so the speedometer reads low. Moving from a 31.6in tire to a 34.8in tire is a 10% increase in diameter. At a true 60 mph the speedometer would show about 54.5 mph. NHTSA's guidance is to buy the size on the door-jamb placard or another size the vehicle maker recommends. Whatever size you choose, the tires on each axle must still add up to at least the axle's gross axle weight rating under FMVSS 110.