Comparison
225/35 R19 vs 245/40 R18
245/40 R18 drops the rim from 19 to 18 inches versus 225/35 R19, trading wheel size for taller sidewall. This sizing approach shifts overall diameter slightly from OEM. More sidewall typically improves comfort and curb protection, especially on city streets.
The speedometer offset is small but measurable; worth keeping in mind if you watch the dash closely. Diameter change stays inside the conservative ±3% safety window — an OEM-safe fitment on most vehicles.
TakeTypical choice for a dedicated winter or off-road setup where extra sidewall pays off.
Quick math: 245/40 R18 is 13.1 mm taller than 225/35 R19, shifting the speedometer by +2.05%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
+13.1 mm
2.05%
Speedometer at 100
102.0 km/h
+2.05% error
Ground clearance
+6.6 mm
ride height delta
Sidewall change
+19.3 mm
revs/km: 487.3
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/compare/225-35-r19-vs-245-40-r18Detailed comparison
| Metric | 225/35 R19 | 245/40 R18 | Difference |
|---|---|---|---|
| Overall diameter | 640.1 mm | 653.2 mm | +13.1 mm (+2.05%) |
| Sidewall height | 78.8 mm | 98.0 mm | +19.3 mm |
| Circumference | 2.011 m | 2.052 m | +41.2 mm |
| Revs / km | 497.3 | 487.3 | -10.0 |
| Ground clearance | reference | +6.6 mm | +6.6 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 102.0 km/h | +2.05 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 102.0 km/h after switching to 245/40 R18 — a +2.05% 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 +6.6 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
225/35 R19
Back to
245/40 R18
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