Comparison
215/40 R18 vs 225/50 R17
225/50 R17 drops the rim from 18 to 17 inches versus 215/40 R18, trading wheel size for taller sidewall. This sizing approach swings rolling diameter far enough to feel on the road.
The speedometer error is noticeable and may warrant a recalibration if you rely on indicated speed. Extra sidewall absorbs impacts more readily — a sensible bias for daily commuting and broken pavement. More tread on the ground tends to improve dry grip and stance, with a small fuel-economy and clearance tradeoff. Minus-sizing keeps replacement costs down and opens up a wider range of winter and all-terrain tires. Diameter delta falls in the cautious 3–5% range, where speedometer recalibration and a careful clearance check are worth doing.
TakeTypical choice for a dedicated winter or off-road setup where extra sidewall pays off.
Quick math: 225/50 R17 is 27.6 mm taller than 215/40 R18, shifting the speedometer by +4.39%.
Current Tire
New Tire
Ground line · scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
+27.6 mm
4.39%
Speedometer at 100
104.4 km/h
+4.39% error
Ground clearance
+13.8 mm
ride height delta
Sidewall change
+26.5 mm
revs/km: 484.6
Permalink for this comparison:
/compare/215-40-r18-vs-225-50-r17Detailed comparison
| Metric | 215/40 R18 | 225/50 R17 | Difference |
|---|---|---|---|
| Overall diameter | 629.2 mm | 656.8 mm | +27.6 mm (+4.39%) |
| Sidewall height | 86.0 mm | 112.5 mm | +26.5 mm |
| Circumference | 1.977 m | 2.063 m | +86.7 mm |
| Revs / km | 505.9 | 484.6 | -21.3 |
| Ground clearance | reference | +13.8 mm | +13.8 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 104.4 km/h | +4.39 km/h |
Verdict: warning
Between 3% and 5% — noticeable speedometer drift; recalibration may be advisable.
Speedometer impact
At a true 100 km/h, your dashboard will read 104.4 km/h after switching to 225/50 R17 — a +4.39% 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 +13.8 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
215/40 R18
Back to
225/50 R17
Drivers also compare
Closely-related fitments and plus-size swaps for 215/40 R18 and 225/50 R17.
215/40 R18 vs 245/35 R18
Wider variation on the same rim — more grip, less clearance.
Δ 0.08%
225/50 R17 vs 245/45 R17
Wider variation on the same rim — more grip, less clearance.
Δ 0.69%
215/40 R18 vs 255/35 R18
Wider variation on the same rim — more grip, less clearance.
Δ 1.03%
215/40 R18 vs 225/40 R18
Wider variation on the same rim — more grip, less clearance.
Δ 1.27%
215/50 R17 vs 225/50 R17
Wider variation on the same rim — more grip, less clearance.
Δ 1.55%
215/55 R17 vs 225/50 R17
Wider variation on the same rim — more grip, less clearance.
Δ 1.72%
225/50 R17 vs 235/45 R17
Wider variation on the same rim — more grip, less clearance.
Δ 2.06%
215/40 R18 vs 235/40 R18
Wider variation on the same rim — more grip, less clearance.
Δ 2.54%
Related topics