235/65R17 vs 245/65R17
Diameter +1.76% · Speedo at 60 mph reads 61.1 mph actual · Ground clearance +6.5 mm
Generally safe — within the 3% tolerance
The diameter difference is ≤3%, which is the widely-accepted fitment tolerance for speedometer accuracy and ABS/traction-control calibration. Verify clearance and load rating with a tire professional before installing.
Speedometer effect
When the vehicle's speedometer (calibrated to 235/65R17) reads 60 mph, the actual speed with 245/65R17 mounted is:
Speedometer error: +1.77% · Odometer reads high by 1.77%
Full comparison
| Measurement | 235/65R17 | 245/65R17 | Delta |
|---|---|---|---|
| Overall diameter | 29.03" | 29.54" | +1.76% |
| Section width | 235 mm | 245 mm | +10 mm |
| Sidewall height | 152.75 mm | 159.25 mm | +6.50 mm |
| Rim diameter | 17" | 17" | +0" |
| Circumference | 2316 mm | 2357 mm | +41 mm |
| Revs / mile | 695 | 683 | -12 |
| Ground clearance change | +6.5 mm | ||
Questions about this swap
What is the diameter difference between 235/65R17 and 245/65R17?
245/65R17 is 1.76% larger in overall diameter than 235/65R17 — a difference of 13.0 mm (0.51 inches).
How does 245/65R17 affect the speedometer if the car was calibrated for 235/65R17?
When the speedometer reads 60 mph (calibrated for 235/65R17), the actual speed with 245/65R17 is 61.1 mph — an error of +1.77%.
Is it safe to replace 235/65R17 with 245/65R17?
Generally safe — within the 3% tolerance. The diameter difference is ≤3%, which is the widely-accepted fitment tolerance for speedometer accuracy and ABS/traction-control calibration. Verify clearance and load rating with a tire professional before installing.
All calculations use standard ETRTO formulas. Confirm fitment with a qualified tire professional and your vehicle's door-placard before purchasing.