235/60R18 vs 245/60R18
Side-by-side comparison of overall diameter, sidewall height, speedometer error, and ride-height change.
Borderline — Check wheel-arch clearance and reset TPMS before fitting.
To scale
235/60R18
- Section width
- 235 mm
- Aspect ratio
- 60%
- Rim diameter
- 18"
- Sidewall
- 141.0 mm
- Overall diameter
- 739.2 mm
- Circumference
- 2322 mm
- Revs / mile
- 693
- Revs / km
- 431
245/60R18
- Section width
- 245 mm
- Aspect ratio
- 60%
- Rim diameter
- 18"
- Sidewall
- 147.0 mm
- Overall diameter
- 751.2 mm
- Circumference
- 2360 mm
- Revs / mile
- 682
- Revs / km
- 424
Difference
- Overall diameter
- +12.0 mm (+1.62%)
- Sidewall height
- +6.0 mm
- Tread width
- +10 mm
- Ride height (axle)
- +6.0 mm
- Speedometer error
- +1.62%
- At indicated 60 mph
- actual 61.0 mph
- At indicated 100 km/h
- actual 101.6 km/h
Will 245/60R18 fit instead of 235/60R18?
The overall diameter changes by 1.62%. Most manufacturers consider a swap acceptable when the difference stays under 3% — beyond that, you may see speedometer error, ABS/TPMS warnings, or wheel-well clearance problems. This page only covers the math; your vehicle's wheel arches, suspension geometry, and load rating still matter.
What the numbers mean
- Overall diameter — outside-to-outside height of the tire. Affects ride height, gearing, and speedometer calibration.
- Sidewall height — rubber from rim edge to tread. Lower sidewall gives sharper steering response but a harsher ride.
- Speedometer error — how far off your indicated speed will be after the swap. Positive means the speedo under-reads (actual speed is higher than shown).