Comparison
235/40 R18 vs 245/35 R18
Stepping from 235/40 R18 to 245/35 R18 keeps the 18-inch wheel but widens the section by 10 mm. This swap trims or stretches rolling diameter by a small margin. Expect a slight but noticeable shift in indicated speed compared to the original tires. Expect a more planted steering feel, at the cost of some of the cushioning a taller sidewall provides. Overall the swap sits inside the safe ±3% diameter window, so ABS, traction control and gearing behave normally.
TakeReasonable performance-leaning swap as long as fender and suspension clearance check out.
Quick math: 245/35 R18 is 16.5 mm shorter than 235/40 R18, shifting the speedometer by -2.56%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
-16.5 mm
-2.56%
Speedometer at 100
97.4 km/h
-2.56% error
Ground clearance
-8.3 mm
ride height delta
Sidewall change
-8.3 mm
revs/km: 506.3
Permalink for this comparison:
/compare/235-40-r18-vs-245-35-r18Detailed comparison
| Metric | 235/40 R18 | 245/35 R18 | Difference |
|---|---|---|---|
| Overall diameter | 645.2 mm | 628.7 mm | -16.5 mm (-2.56%) |
| Sidewall height | 94.0 mm | 85.8 mm | -8.3 mm |
| Circumference | 2.027 m | 1.975 m | -51.8 mm |
| Revs / km | 493.4 | 506.3 | +12.9 |
| Ground clearance | reference | -8.3 mm | -8.3 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 97.4 km/h | -2.56 km/h |
Verdict: excellent
Within ±3% — speedometer, ABS and traction control should behave normally.
Speedometer impact
At a true 100 km/h, your dashboard will read 97.4 km/h after switching to 245/35 R18 — a -2.56% offset. Use the speedometer error calculator to recheck for other indicated speeds, and the speedometer error guide for the full background.
Ground clearance change
The new tire's half-diameter changes ride height by -8.3 mm. Small differences are absorbed by suspension travel, but anything beyond ±10 mm can affect headlight aim, fender clearance and bump-stop margin. See the plus-sizing guide before committing.
Back to
235/40 R18
Back to
245/35 R18
Drivers also compare
Closely-related fitments and plus-size swaps for 235/40 R18 and 245/35 R18.
215/40 R18 vs 245/35 R18
Wider variation on the same rim — more grip, less clearance.
Δ 0.08%
235/40 R18 vs 275/35 R18
Wider variation on the same rim — more grip, less clearance.
Δ 0.70%
215/45 R18 vs 235/40 R18
Wider variation on the same rim — more grip, less clearance.
Δ 0.85%
245/35 R18 vs 255/35 R18
Wider variation on the same rim — more grip, less clearance.
Δ 1.11%
235/40 R18 vs 245/40 R18
Wider variation on the same rim — more grip, less clearance.
Δ 1.24%
225/40 R18 vs 235/40 R18
Wider variation on the same rim — more grip, less clearance.
Δ 1.26%
225/40 R18 vs 245/35 R18
Wider variation on the same rim — more grip, less clearance.
Δ 1.33%
235/40 R18 vs 255/35 R18
Wider variation on the same rim — more grip, less clearance.
Δ 1.47%
Related topics