Comparison
215/45 R18 vs 215/50 R17
Going from 215/45 R18 to 215/50 R17 is a minus-1 setup that adds sidewall on a smaller 17-inch wheel. This swap keeps overall diameter very close to stock.
Dashboard speed shifts only marginally — within the noise of normal OEM tolerance. More sidewall typically improves comfort and curb protection, especially on city streets. Minus-sizing keeps replacement costs down and opens up a wider range of winter and all-terrain tires. Overall the swap sits inside the safe ±3% diameter window, so ABS, traction control and gearing behave normally.
TakeTypical choice for a dedicated winter or off-road setup where extra sidewall pays off.
Quick math: 215/50 R17 is 3.9 mm shorter than 215/45 R18, shifting the speedometer by -0.60%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
-3.9 mm
-0.60%
Speedometer at 100
99.4 km/h
-0.60% error
Ground clearance
-2.0 mm
ride height delta
Sidewall change
+10.8 mm
revs/km: 492.1
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/compare/215-45-r18-vs-215-50-r17Detailed comparison
| Metric | 215/45 R18 | 215/50 R17 | Difference |
|---|---|---|---|
| Overall diameter | 650.7 mm | 646.8 mm | -3.9 mm (-0.60%) |
| Sidewall height | 96.8 mm | 107.5 mm | +10.8 mm |
| Circumference | 2.044 m | 2.032 m | -12.3 mm |
| Revs / km | 489.2 | 492.1 | +2.9 |
| Ground clearance | reference | -2.0 mm | -2.0 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 99.4 km/h | -0.60 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 99.4 km/h after switching to 215/50 R17 — a -0.60% 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 -2.0 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.
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215/45 R18
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215/50 R17
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