tireheight.com305/55R20 in inches
A 305/55R20 tire is 33.2″ tall and 12.0″ wide, and fits a 20″ wheel. In inches it is written 33.2×12.0R20.
How tall 305/55R20 tires really are
Heights published by BFGoodrich, General, Mickey Thompson and Toyo for all 14 tires in this size. Their published revolutions per mile work out to 32.2–32.5″ under load (below).
Real 305/55R20 tires measure 33.20–33.70″, against 33.21″ from the size code. They run both taller and shorter than the size code.
- Mickey Thompson Baja Boss A/T33.70″ +0.49″
- Mickey Thompson Baja Boss M/T33.50″ +0.29″
- Mickey Thompson Baja Legend MTZ33.50″ +0.29″
- Toyo Open Country M/T33.46″ +0.26″
- Mickey Thompson Baja Legend EXP33.40″ +0.19″
- Toyo Open Country R/T Trail · 233.23–33.23″ +0.02″
- Toyo Open Country A/T III · 233.20–33.23″ +0.02″
- BFGoodrich All-Terrain T/A KO333.20″ −0.01″
- BFGoodrich Mud-Terrain T/A KM333.20″ −0.01″
- General Grabber A/TX33.20″ −0.01″
- General Grabber X333.20″ −0.01″
- Toyo Open Country R/T Pro33.20″ −0.01″
Published revs per mile (621–626) mean the tire rolls like a 32.2–32.5″ tire on the vehicle. Use this for speedometer calibration.
The lightest (Toyo Open Country A/T III, SL) is 21.5 lb lighter per corner than the heaviest (BFGoodrich Mud-Terrain T/A KM3, LT E).
14 tires in 305/55R20
Sort by the spec you care about.
| Load | Revs/mi | Source | |||||
|---|---|---|---|---|---|---|---|
| Toyo Open Country A/T IIIAll-terrain | SL · 116S | 33.20 | 49.4 | 13.9 | 2,756 | 625 | Spec page |
| Toyo Open Country R/T TrailRugged-terrain | SL · 116Q | 33.23 | 52.7 | 13.9 | 2,756 | 625 | Spec page |
| General Grabber A/TXAll-terrain | LT E · 121S | 33.20 | 59.8 | 16.0 | 3,195 | 626 | Spec page |
| Mickey Thompson Baja Legend EXPAll-terrain | LT F · 125Q | 33.40 | 64.0 | 18.5 | 3,640 | – | Spec page |
| Toyo Open Country A/T IIIAll-terrain | LT F · 125/122Q | 33.23 | 64.7 | 16.8 | 3,640 | 625 | Spec page |
| Toyo Open Country R/T ProRugged-terrain | LT F · 125/122Q | 33.20 | 66.2 | 17.1 | 3,640 | 625 | Spec page |
| Toyo Open Country R/T TrailRugged-terrain | LT F · 125/122Q | 33.23 | 66.6 | 16.8 | 3,640 | 625 | Spec page |
| BFGoodrich All-Terrain T/A KO3All-terrain | LT F · 125S | 33.20 | 67.0 | 16.0 | 3,640 | 626 | Spec page |
| General Grabber X3Mud-terrain | LT E · 121Q | 33.20 | 68.0 | 19.0 | 3,195 | 626 | Spec page |
| Mickey Thompson Baja Legend MTZMud-terrain | LT F · 125Q | 33.50 | 68.0 | 20.5 | 3,640 | – | Spec page |
| Toyo Open Country M/TMud-terrain | LT F · 125/122Q | 33.46 | 69.9 | 19.5 | 3,640 | 621 | Spec page |
| Mickey Thompson Baja Boss A/TAll-terrain | LT F · 125Q | 33.70 | 70.0 | 18.5 | 3,640 | – | Spec page |
| Mickey Thompson Baja Boss M/TMud-terrain | LT F · 125Q | 33.50 | 70.0 | 20.5 | 3,640 | – | Spec page |
| BFGoodrich Mud-Terrain T/A KM3Mud-terrain | LT E · 121Q | 33.20 | 70.9 | 18.0 | 3,195 | 626 | Spec page |
Is 305/55R20 a 33-inch tire?
Yes. The size code works out to 33.21″, and the 14 tires here publish 33.20–33.70″, so people call it a 33.
All 33-inch tire sizes, on every wheel size.
A true 33×11.50R20 is 0.21″ shorter on paper and 0.5″ narrower.
Compare with nearby sizes
Differences in overall diameter, calculated from each size code.
| Size | Diameter ″ | vs 305/55R20 | Difference |
|---|---|---|---|
| 285/55R20 | 32.34 | -0.87″ | -2.6% |
| 265/60R20 | 32.52 | -0.69″ | -2.1% |
| 295/55R20 | 32.78 | -0.43″ | -1.3% |
| 275/60R20 | 32.99 | -0.22″ | -0.7% |
| 33×11.50R20 | 33.00 | -0.21″ | -0.6% |
| 33×12.50R20 | 33.00 | -0.21″ | -0.6% |
| 33×13.50R20 | 33.00 | -0.21″ | -0.6% |
| 285/60R20 | 33.46 | +0.26″ | +0.8% |
| 295/60R20 | 33.94 | +0.73″ | +2.2% |
| 275/65R20 | 34.07 | +0.87″ | +2.6% |
How to read 305/55R20
Marks a light truck (LT) tire.
A percentage, not a measurement: the sidewall is 55% as tall as the tire is wide, which is 167.8 mm or 6.60 inches.
Radial construction.
Mounts on a 20-inch wheel. Approved wheel widths run 8.5″ to 11.0″.
Each tire carries up to 3,640 lb (1,650 kg) at its maximum pressure.
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 3,640 lb each, as published.
| Specification | Inches | Metric |
|---|---|---|
| Overall diameter | 33.21 | 844 mm |
| Section width | 12.01 | 305 mm |
| Sidewall height | 6.60 | 167.8 mm |
| Circumference | 104.3 | 2,650 mm |
| Revolutions per mile (calculated, unloaded) | 607.3 | 377 per km |
| Revolutions per mile (published by manufacturers) | 621–626 | 386–389 per km |
| Approved wheel width | 8.5–11.0 | 216–279 mm |
Speedometer error after switching to 305/55R20
Questions about 305/55R20
What is 305/55R20 in inches?
33.21 inches tall, 12.01 inches wide, on a 20-inch wheel. Written in inches, that is roughly 33.2×12.0R20.
How much does a 305/55R20 tire weigh?
Between 49.4 lb and 70.9 lb for the 14 tires listed here. The lightest is the Toyo Open Country A/T III (SL); the heaviest is the BFGoodrich Mud-Terrain T/A KM3 (LT E).
What wheel width do I need for 305/55R20?
Manufacturers approve 8.5–11.0″ wide wheels for this size.
How many revolutions per mile does a 305/55R20 make?
Published figures run 621–626 revolutions per mile. The calculated figure is 607.3, but manufacturers measure the tire under load, where it rolls on a smaller radius.
What is the difference between P305/55R20 and LT305/55R20?
Passenger tires (2 here) are built for passenger loads, with max loads of 2756 lb. Light-truck tires (12 here) come in heavier load ranges with max loads of 3195–3640 lb, and are usually heavier with deeper tread.
How much taller is 305/55R20 than 33×13.50R20?
0.21 inches taller on paper (33.21″ vs 33.00″), which raises the axle about 0.10″. Your speedometer will read about 0.6% slow.