295/70R17 vs 295/65R18 Side-by-side tire size comparison with specs and compatibility
Compatibility
-0.49% diameter difference
✓ Safe Swap
This tire swap is within the safe 3% diameter threshold. It should not cause issues with speedometer accuracy, ABS, or traction control systems.
Full Specifications Comparison
| Specification | 295/70R17 | 295/65R18 | Difference |
|---|---|---|---|
| Overall Diameter | 844.8 mm (33.3") | 840.7 mm (33.1") | -4.1 mm |
| Section Width | 295 mm (11.6") | 295 mm (11.6") | 0 mm |
| Sidewall Height | 206.5 mm | 191.8 mm | -14.7 mm |
| Circumference | 2654 mm | 2641.1 mm | -12.9 mm |
| Revolutions/Mile | 606 | 609 | +3 |
| Aspect Ratio | 70% | 65% | -5% |
| Rim Diameter | 17" | 18" | +1" |
Key Impact Summary
Ground Clearance
-2 mm
Speedometer Error
-0.49%
Width Change
0 mm
Sidewall Change
-14.7 mm
Speedometer Correction Table
When switching from 295/70R17 to 295/65R18, your speedometer will over-read. Here is the correction at common speeds:
| Speedometer Shows | Actual Speed (mph) | Difference |
|---|---|---|
| 30 mph | 29.9 mph | -0.1 mph |
| 40 mph | 39.8 mph | -0.2 mph |
| 50 mph | 49.8 mph | -0.2 mph |
| 60 mph | 59.7 mph | -0.3 mph |
| 70 mph | 69.7 mph | -0.3 mph |
| 80 mph | 79.6 mph | -0.4 mph |
| 90 mph | 89.6 mph | -0.4 mph |
| 100 mph | 99.5 mph | -0.5 mph |
| 110 mph | 109.5 mph | -0.5 mph |
| 120 mph | 119.4 mph | -0.6 mph |
What This Swap Means
Shorter sidewall: The 14.7mm decrease in sidewall height improves steering response and cornering precision. However, ride quality becomes firmer and the wheels are more vulnerable to pothole damage. This is a common trade-off when upsizing wheels (plus-sizing).
Ground clearance: Decreases by 2mm, lowering the center of gravity slightly which can improve handling stability.
Related Comparisons
Individual Tire Specs
Frequently Asked Questions
Yes, this swap is generally safe. The diameter difference is -0.49% (-4.1mm). This is within the safe 3% threshold and should not significantly affect your speedometer, ABS, or traction control.
Switching from 295/70R17 to 295/65R18 creates a -0.49% speedometer error. Your actual speed will be slower than displayed — at an indicated 60 mph, you'll actually be going 59.7 mph.
Switching from 295/70R17 to 295/65R18 changes ground clearance by -2mm. The vehicle will sit 2mm lower. Ground clearance change equals half the overall diameter difference.