Comparison
215/65 R16 vs 265/40 R18
Going from 215/65 R16 to 265/40 R18 steps up to a 18-inch rim while trimming sidewall to stay near OEM rolling diameter. This alternative fitment shifts overall diameter slightly from OEM.
Expect a slight but noticeable shift in indicated speed compared to the original tires. Less sidewall flex usually translates to crisper turn-in and a slightly stiffer ride over rough pavement. More tread on the ground tends to improve dry grip and stance, with a small fuel-economy and clearance tradeoff. Visually, the bigger wheel fills the arch and gives the car a more aggressive stance. Diameter change stays inside the conservative ±3% safety window — an OEM-safe fitment on most vehicles.
TakeA solid pick for drivers chasing a more aggressive stance without abandoning OEM rolling diameter.
Quick math: 265/40 R18 is 16.7 mm shorter than 215/65 R16, shifting the speedometer by -2.43%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
-16.7 mm
-2.43%
Speedometer at 100
97.6 km/h
-2.43% error
Ground clearance
-8.3 mm
ride height delta
Sidewall change
-33.8 mm
revs/km: 475.7
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/compare/215-65-r16-vs-265-40-r18Detailed comparison
| Metric | 215/65 R16 | 265/40 R18 | Difference |
|---|---|---|---|
| Overall diameter | 685.9 mm | 669.2 mm | -16.7 mm (-2.43%) |
| Sidewall height | 139.8 mm | 106.0 mm | -33.8 mm |
| Circumference | 2.155 m | 2.102 m | -52.5 mm |
| Revs / km | 464.1 | 475.7 | +11.6 |
| Ground clearance | reference | -8.3 mm | -8.3 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 97.6 km/h | -2.43 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 97.6 km/h after switching to 265/40 R18 — a -2.43% 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
215/65 R16
Back to
265/40 R18
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