Tire Size Calculator
Compare two tire sizes side-by-side. See diameter, sidewall, circumference, speedometer impact, and fitment considerations.
Original Tire
/R
245/65R17
New Tire
/R
265/70R17
- Significant height increase — check fender and suspension clearance before installing.
Visual Comparison
Original
New
Key Differences
Overall Diameter+2.07" / +52.5 mm
Section Width+20 mm / +0.79"
Sidewall Height+1.03" / +26.3 mm
Ground Clearance+1.03" radius change
Revs per Mile-44.6 rev/mi
Full Measurements
| Measurement | Original 245/65R17 | New 265/70R17 | Difference |
|---|---|---|---|
| Overall Diameter | 29.54" (750.3 mm) | 31.61" (802.8 mm) | +2.1 " |
| Section Width | 245 mm (9.65") | 265 mm (10.43") | +20.0 mm |
| Sidewall Height | 159.3 mm (6.27") | 185.5 mm (7.30") | +1.0 " |
| Rim Diameter | 17" | 17" | No change |
| Circumference | 92.80" | 99.29" | +6.5 " |
| Revolutions / Mile | 682.8 | 638.1 | -44.6 |
Speedometer Impact
Your speedometer is calibrated for the original tire. With new tires installed, your actual speed will differ.
Actual speed
69.5 mph
Error
+7.00%
Speedo reads low — you're going faster than it shows.
| Speedo reads | 30 | 45 | 55 | 65 | 70 | 75 | 80 |
|---|---|---|---|---|---|---|---|
| Actual speed | 32.1 | 48.1 | 58.8 | 69.5 | 74.9 | 80.2 | 85.6 |
Reading a Tire Size
265/70R17
265 — section width in millimeters
265/70R17
70 — aspect ratio: sidewall height is 70% of section width
265/70R17
17 — rim/wheel diameter in inches