tireheight.com305/65R18 in inches
A 305/65R18 tire is 33.6″ tall and 12.0″ wide, and fits a 18″ wheel. In inches it is written 33.6×12.0R18.
How tall 305/65R18 tires really are
Heights published by BFGoodrich and Toyo for all 4 tires in this size. Their published revolutions per mile work out to 32.6–32.8″ under load (below).
Real 305/65R18 tires measure 33.58–33.82″, against 33.61″ from the size code. They run both taller and shorter than the size code.
- Toyo Open Country M/T33.82″ +0.21″
- BFGoodrich All-Terrain T/A KO333.60″ −0.01″
- Toyo Open Country R/T Pro33.60″ −0.01″
- Toyo Open Country A/T III33.58″ −0.03″
Published revs per mile (614–619) mean the tire rolls like a 32.6–32.8″ tire on the vehicle. Use this for speedometer calibration.
The lightest (Toyo Open Country A/T III, LT F) is 5.7 lb lighter per corner than the heaviest (Toyo Open Country M/T, LT F).
4 tires in 305/65R18
Sort by the spec you care about.
| Load | Revs/mi | Source | |||||
|---|---|---|---|---|---|---|---|
| Toyo Open Country A/T IIIAll-terrain | LT F · 128/125Q | 33.58 | 64.9 | 16.8 | 3,970 | 619 | Spec page |
| BFGoodrich All-Terrain T/A KO3All-terrain | LT F · 128S | 33.60 | 65.1 | 16.0 | 3,970 | 619 | Spec page |
| Toyo Open Country R/T ProRugged-terrain | LT F · 128/125Q | 33.60 | 67.0 | 17.1 | 3,970 | 619 | Spec page |
| Toyo Open Country M/TMud-terrain | LT F · 128/125Q | 33.82 | 70.5 | 19.5 | 3,970 | 614 | Spec page |
Is 305/65R18 a 34-inch tire?
Yes. The size code works out to 33.61″, and the 4 tires here publish 33.58–33.82″, so people call it a 34.
All 34-inch tire sizes, on every wheel size.
Compare with nearby sizes
Differences in overall diameter, calculated from each size code.
How to read 305/65R18
Marks a light truck (LT) tire.
A percentage, not a measurement: the sidewall is 65% as tall as the tire is wide, which is 198.3 mm or 7.81 inches.
Radial construction.
Mounts on a 18-inch wheel. Approved wheel widths run 8.5″ to 11.0″.
Each tire carries up to 3,970 lb (1,800 kg) on its own, or 3,640 lb (1,650 kg) each when paired on a dual rear axle.
Rated for up to 99 mph sustained.
Printed separately as "LOAD RANGE F": a 12-ply rating, inflated up to 95 psi (standard load-range table). The load range F tires here carry up to 3,970 lb each, as published.
| Specification | Inches | Metric |
|---|---|---|
| Overall diameter | 33.61 | 854 mm |
| Section width | 12.01 | 305 mm |
| Sidewall height | 7.81 | 198.3 mm |
| Circumference | 105.6 | 2,682 mm |
| Revolutions per mile (calculated, unloaded) | 600.1 | 373 per km |
| Revolutions per mile (published by manufacturers) | 614–619 | 382–385 per km |
| Approved wheel width | 8.5–11.0 | 216–279 mm |
Speedometer error after switching to 305/65R18
Questions about 305/65R18
What is 305/65R18 in inches?
33.61 inches tall, 12.01 inches wide, on a 18-inch wheel. Written in inches, that is roughly 33.6×12.0R18.
How much does a 305/65R18 tire weigh?
Between 64.9 lb and 70.5 lb for the 4 tires listed here. The lightest is the Toyo Open Country A/T III (LT F); the heaviest is the Toyo Open Country M/T (LT F).
What wheel width do I need for 305/65R18?
Manufacturers approve 8.5–11.0″ wide wheels for this size.
How many revolutions per mile does a 305/65R18 make?
Published figures run 614–619 revolutions per mile. The calculated figure is 600.1, but manufacturers measure the tire under load, where it rolls on a smaller radius.
How much taller is 305/65R18 than 325/60R18?
0.26 inches taller on paper (33.61″ vs 33.35″), which raises the axle about 0.13″. Your speedometer will read about 0.8% slow.