Comparison
235/35 R19 vs 245/40 R18
Switching from 235/35 R19 to 245/40 R18 steps down to a 18-inch wheel — a familiar move for winter and dedicated all-terrain sets. This wheel and tire pairing preserves rolling diameter within a hair of the original. The speedometer offset is mild and well inside what most cars can tolerate without recalibration. The taller sidewall adds cushioning over potholes and rougher roads, with a softer overall ride. Overall the swap sits inside the safe ±3% diameter window, so ABS, traction control and gearing behave normally.
TakePractical direction for winter wheels, chains, or rougher pavement where cushioning matters.
Quick math: 245/40 R18 is 6.1 mm taller than 235/35 R19, shifting the speedometer by +0.94%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
+6.1 mm
0.94%
Speedometer at 100
100.9 km/h
+0.94% error
Ground clearance
+3.1 mm
ride height delta
Sidewall change
+15.8 mm
revs/km: 487.3
Permalink for this comparison:
/compare/235-35-r19-vs-245-40-r18Detailed comparison
| Metric | 235/35 R19 | 245/40 R18 | Difference |
|---|---|---|---|
| Overall diameter | 647.1 mm | 653.2 mm | +6.1 mm (+0.94%) |
| Sidewall height | 82.3 mm | 98.0 mm | +15.8 mm |
| Circumference | 2.033 m | 2.052 m | +19.2 mm |
| Revs / km | 491.9 | 487.3 | -4.6 |
| Ground clearance | reference | +3.1 mm | +3.1 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 100.9 km/h | +0.94 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 100.9 km/h after switching to 245/40 R18 — a +0.94% 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 +3.1 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
235/35 R19
Back to
245/40 R18
Drivers also compare
Closely-related fitments and plus-size swaps for 235/35 R19 and 245/40 R18.
215/45 R18 vs 245/40 R18
Wider variation on the same rim — more grip, less clearance.
Δ 0.38%
245/40 R18 vs 275/35 R18
Wider variation on the same rim — more grip, less clearance.
Δ 0.54%
225/45 R18 vs 245/40 R18
Wider variation on the same rim — more grip, less clearance.
Δ 0.99%
235/35 R19 vs 245/35 R19
Wider variation on the same rim — more grip, less clearance.
Δ 1.08%
225/35 R19 vs 235/35 R19
Wider variation on the same rim — more grip, less clearance.
Δ 1.09%
245/40 R18 vs 255/40 R18
Wider variation on the same rim — more grip, less clearance.
Δ 1.22%
235/40 R18 vs 245/40 R18
Wider variation on the same rim — more grip, less clearance.
Δ 1.24%
235/35 R19 vs 255/35 R19
Wider variation on the same rim — more grip, less clearance.
Δ 2.16%
Related topics