235/55R18 vs 235/60R18: Tire Size Comparison
235/60R18 is 0.93 inches taller than 235/55R18 (29.1″ vs 28.18″, +3.28%) and 0 inches wider. The difference is outside the common ±3% guideline. At an indicated 60 mph you would be doing 62 mph.
| 235/55R18 | 235/60R18 | Difference | |
|---|---|---|---|
| Overall diameter | 28.18 in | 29.1 in | +0.93 |
| Section width | 9.25 in | 9.25 in | +0 |
| Sidewall height | 5.09 in | 5.55 in | +0.46 |
| Circumference | 88.5 in | 91.4 in | +2.91 |
| Revolutions per mile | 716 | 693 | −23 |
235/55R18 vs 235/60R18 dimensions
| 235/55R18 | 235/60R18 | Difference | |
|---|---|---|---|
| Overall diameter | 28.18 in (716 mm) | 29.1 in (739 mm) | +0.93 in (+3.28%) |
| Section width | 9.25 in | 9.25 in | +0 in |
| Sidewall height | 5.09 in | 5.55 in | +0.46 in |
| Wheel diameter | 18 in | 18 in | same wheel |
| Circumference | 88.5 in | 91.4 in | +2.91 in |
| Revolutions per mile | 716 | 693 | -23 |
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 | 31 mph | +1 mph |
| 45 mph | 46.5 mph | +1.5 mph |
| 60 mph | 62 mph | +2 mph |
| 70 mph | 72.3 mph | +2.3 mph |
| 80 mph | 82.6 mph | +2.6 mph |
Assumes your speedometer is accurate on 235/55R18. Because 235/60R18 is taller, you travel slightly faster than indicated and the odometer under-counts: 10,000 miles on the odometer is about 10,328 real miles.
What changes if you switch
- Ride height: up about 0.46 in (half the diameter change).
- Wheels: both fit a 18-inch wheel; check the tire's approved rim width range.
- Sidewall: a taller sidewall usually rides softer and resists pothole damage, with a little less steering sharpness.
- 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 235/55R18?
235/60R18 is +3.28% in overall diameter compared with 235/55R18 (29.1″ vs 28.18″). That is outside the common ±3% guideline, so it is a bigger change that may affect the speedometer, ABS and clearance. Check your vehicle placard, load index, speed rating and clearance before switching.
How much taller is 235/60R18 than 235/55R18?
235/60R18 is 0.93 inches taller overall, which raises ride height by about 0.46 inches. Sidewall height changes from 5.09″ to 5.55″.
How much wider is 235/60R18 than 235/55R18?
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 235/55R18, when the speedometer shows 60 mph you are actually going about 62 mph. The odometer will record 10,000 miles when you have driven about 10,328.