235/65R17 vs 235/60R18: Tire Size Comparison
235/60R18 is 0.07 inches taller than 235/65R17 (29.1″ vs 29.03″, +0.26%) and 0 inches wider. The difference is within the common ±3% guideline. At an indicated 60 mph you would be doing 60.2 mph.
| 235/65R17 | 235/60R18 | Difference | |
|---|---|---|---|
| Overall diameter | 29.03 in | 29.1 in | +0.07 |
| Section width | 9.25 in | 9.25 in | +0 |
| Sidewall height | 6.01 in | 5.55 in | −0.46 |
| Circumference | 91.2 in | 91.4 in | +0.24 |
| Revolutions per mile | 695 | 693 | −2 |
235/65R17 vs 235/60R18 dimensions
| 235/65R17 | 235/60R18 | Difference | |
|---|---|---|---|
| Overall diameter | 29.03 in (737 mm) | 29.1 in (739 mm) | +0.07 in (+0.26%) |
| Section width | 9.25 in | 9.25 in | +0 in |
| Sidewall height | 6.01 in | 5.55 in | −0.46 in |
| Wheel diameter | 17 in | 18 in | +1 in |
| Circumference | 91.2 in | 91.4 in | +0.24 in |
| Revolutions per mile | 695 | 693 | -2 |
Nominal dimensions calculated from the size code. Real tires vary slightly by brand, tread depth and inflation.
Speedometer difference with 235/60R18
| Speedometer shows | Actual speed on 235/60R18 | Difference |
|---|---|---|
| 30 mph | 30.1 mph | +0.1 mph |
| 45 mph | 45.1 mph | +0.1 mph |
| 60 mph | 60.2 mph | +0.2 mph |
| 70 mph | 70.2 mph | +0.2 mph |
| 80 mph | 80.2 mph | +0.2 mph |
Assumes your speedometer is accurate on 235/65R17. Because 235/60R18 is taller, you travel slightly faster than indicated and the odometer under-counts: 10,000 miles on the odometer is about 10,026 real miles.
What changes if you switch
- Ride height: up about 0.04 in (half the diameter change).
- Wheels: 235/60R18 needs a 18-inch wheel, so this is a wheel-and-tire change, not just new tires.
- Sidewall: a shorter sidewall usually sharpens steering but rides firmer and is more prone to pothole damage.
- Effective gearing: slightly taller, so marginally lower engine rpm at speed and slightly slower acceleration.
- Match the original load index and speed rating or higher, and check for rubbing at full steering lock and full suspension compression.
Related tire size comparisons
Frequently asked questions
Can I use 235/60R18 instead of 235/65R17?
235/60R18 is +0.26% in overall diameter compared with 235/65R17 (29.1″ vs 29.03″). That is inside the common ±3% guideline, so it is often used as an alternative and it needs a 18-inch wheel instead of 17-inch. Check your vehicle placard, load index, speed rating and clearance before switching.
How much taller is 235/60R18 than 235/65R17?
235/60R18 is 0.07 inches taller overall, which raises ride height by about 0.04 inches. Sidewall height changes from 6.01″ to 5.55″.
How much wider is 235/60R18 than 235/65R17?
Section width goes from 9.25″ (235 mm) to 9.25″ (235 mm), a difference of +0 in. Actual width also depends on the rim width it is mounted on.
How does 235/60R18 affect my speedometer?
With 235/60R18 fitted in place of 235/65R17, when the speedometer shows 60 mph you are actually going about 60.2 mph. The odometer will record 10,000 miles when you have driven about 10,026.