LT275/70R18 Tire Size
LT275/70R18 diameter, sidewall, revolutions per mile, and plus-sizing options.
The LT275/70R18 tire size breaks down as: 275 mm section width, 70% aspect ratio, and a 18-inch rim. Below are its real, calculated dimensions.
LT275/70R18 Calculated Dimensions
| Metric | Value |
|---|---|
| Overall diameter | 33.2 in (842 mm) |
| Sidewall height | 7.6 in (193 mm) |
| Circumference | 104.2 in (2646 mm) |
| Revolutions per mile | 608 |
Typical Fitment
LT275/70R18 is most often found on half-ton pickups. Always confirm against the door-jamb placard or owner manual before fitting.
Plus-Sizing Alternatives
These sizes keep the overall diameter close to LT275/70R18, so speedometer and gearing stay near stock:
| Size | Diameter | Diameter change |
|---|---|---|
| 285/70R18 | 33.71 in | +1.7% |
| 285/65R19 | 33.59 in | +1.3% |
| 295/55R20 | 32.78 in | -1.2% |
Speedometer Note
If you fit a 285/70R18 instead of LT275/70R18, the diameter changes by +1.7%. A taller tire makes your speedometer read low — at a true 60 mph it would show roughly 59 mph. A shorter tire has the opposite effect, so the gauge reads high.
Use the tire calculator to compare LT275/70R18 against any other size and see the exact diameter and speedometer difference.
Frequently Asked Questions
What does LT275/70R18 mean?
LT275/70R18 means a 275 mm wide tire with a 70% sidewall aspect ratio mounted on a 18-inch rim. The aspect ratio is the sidewall height as a percentage of the width.
Can I plus-size from LT275/70R18?
Yes, as long as the replacement keeps the overall diameter close to stock so the speedometer stays accurate. Common plus-size moves from LT275/70R18 are 285/70R18, 285/65R19, 295/55R20.
Will LT275/70R18 affect my speedometer?
Only if it differs in diameter from your original size. A taller tire reads low; a shorter tire reads high. Compare the two sizes with the calculator to find the percentage.