Tire size in inches and millimeters
245/70R17 tire size in inches
A 245/70R17 tire is 30.50 inches tall (774.8 mm) and 9.65 inches wide (245 mm), with a 6.75-inch sidewall (171.5 mm). In inch notation that is about 30.5x9.7R17, close to a 31-inch tire (nominal).
Its circumference is 95.83 inches (2,434.1 mm), or about 661 revolutions per mile.
Nominal 245/70R17 dimensions
- Overall diameter
- 30.50 in774.8 mm
- Section width
- 9.65 in245 mm
- Sidewall height
- 6.75 in171.5 mm
- Circumference
- 95.83 in2,434.1 mm
- Rim diameter
- 17 in
- Revolutions per mile
- 661nominal, from geometric circumference
- Inch notation
- 30.5x9.7R17approximate
Where 245/70R17 fits
- Inch class: 30.50 in is near the bottom of the 31-inch class (30.50 to 31.49 in), so some listings call it a 30-inch tire.
- Profile: the 17-inch rim plus two 6.75 in sidewalls make up the overall diameter, and the sidewalls are 44% of it. At 70 series that is a tall profile: the extra sidewall absorbs more of each bump and flexes more in corners.
- Same 17-inch rim: the next taller catalog size is 265/65R17 (30.56 in, +0.19%) and the next shorter is 255/65R17 (30.05 in, -1.48%).
- Same 245 mm width: the closest in diameter are 245/70R16 (29.50 in, -3.28%), 245/65R17 (29.54 in, -3.16%), 245/75R16 (30.47 in, -0.12%), 245/75R17 (31.47 in, +3.16%). At the same width, a different profile or rim changes sidewall height and overall diameter, not section width.
Reading the marking: 245 is the section width in millimeters, 70 is the sidewall height as a percentage of that width, and R17 means radial construction for a 17-inch rim. Percentages are measured from 245/70R17.
Similar sizes on other rim diameters
Within 3% of 245/70R17's overall diameter, nearest first. The speed column is the actual speed when a speedometer calibrated for 245/70R17 reads 60 mph.
| Size | Overall diameter | Diameter change | At 60 mph indicated | Compare |
|---|---|---|---|---|
| 265/60R18 | 30.52 in | +0.05% | 60.03 mph | No comparison page |
| 245/75R16 | 30.47 in | -0.12% | 59.93 mph | Comparison page for 245/70R17 vs 245/75R16 |
| 265/70R16 | 30.61 in | +0.34% | 60.20 mph | No comparison page |
| 215/85R16 | 30.39 in | -0.37% | 59.78 mph | No comparison page |
| 265/75R15 | 30.65 in | +0.48% | 60.29 mph | No comparison page |
| 235/80R16 | 30.80 in | +0.98% | 60.59 mph | Comparison page for 245/70R17 vs 235/80R16 |
For a size without a comparison page, open 245/70R17 in the calculator and enter that size as the proposed tire.
Important: These results compare nominal dimensions. They do not confirm vehicle fitment. Actual clearance varies by tire model, approved rim width, wheel construction, suspension, alignment, body tolerances, steering angle, load, and brake geometry. Verify load and speed ratings and physically test-fit the complete setup before driving.
Physical checks before changing size
- Approved rim-width range for the exact tire model
- Load index and speed rating equal to or greater than vehicle requirements
- Brake-caliper, hub, and wheel-fastener compatibility
- Fender, liner, suspension, and full-lock steering clearance
- Clearance at full compression and under expected load
- Alignment, tire pressure, and manufacturer guidance
- Professional inspection when variance or clearance is uncertain
Compare another setup
See diameter, speedometer, ride-height, and wheel-position changes.
The calculator opens with 245/70R17 as the current tire and 245/75R16, the published comparison closest in overall diameter, as the proposed tire. Change either size; wheel details stay unknown until you supply them.
Compare 245/70R17 with 245/75R16 in the calculatorPublished comparisons for 245/70R17
None keeps the 17-inch rim; each one changes wheel diameter. Diameter changes are measured from 245/70R17.
Smaller wheels
- 245/70R17 vs 235/80R16 +0.98% diameter
- 245/70R17 vs 245/75R16 -0.12% diameter
Size source and limits
Listed as a recorded tire size (source: NHTSA consumer-complaint records through May 2021, checked August 19, 2026; see methodology). A recorded size is not a safety, popularity, availability, or fitment rating.
Read the formulas and source policy. Read the editorial and corrections policy.