37x12.5R17 Tire Size
37x12.5R17 diameter, sidewall, revolutions per mile, and plus-sizing options.
The 37x12.5R17 tire size breaks down as: 318 mm section width, 80% aspect ratio, and a 17-inch rim. Below are its real, calculated dimensions.
37x12.5R17 Calculated Dimensions
| Metric | Value |
|---|---|
| Overall diameter | 37.0 in (940 mm) |
| Sidewall height | 10.0 in (254 mm) |
| Circumference | 116.2 in (2952 mm) |
| Revolutions per mile | 545 |
Typical Fitment
37x12.5R17 is most often found on extreme off-road builds. Always confirm against the door-jamb placard or owner manual before fitting.
Plus-Sizing Alternatives
These sizes keep the overall diameter close to 37x12.5R17, so speedometer and gearing stay near stock:
| Size | Diameter | Diameter change |
|---|---|---|
| 327.5/80R17 | 37.63 in | +1.7% |
| 327.5/75R18 | 37.34 in | +0.9% |
| 337.5/70R19 | 37.60 in | +1.6% |
Speedometer Note
If you fit a 327.5/80R17 instead of 37x12.5R17, 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 37x12.5R17 against any other size and see the exact diameter and speedometer difference.
Frequently Asked Questions
What does 37x12.5R17 mean?
37x12.5R17 means a 318 mm wide tire with a 80% sidewall aspect ratio mounted on a 17-inch rim. The aspect ratio is the sidewall height as a percentage of the width.
Can I plus-size from 37x12.5R17?
Yes, as long as the replacement keeps the overall diameter close to stock so the speedometer stays accurate. Common plus-size moves from 37x12.5R17 are 327.5/80R17, 327.5/75R18, 337.5/70R19.
Will 37x12.5R17 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.