Comparison

225/45 R17 vs 275/35 R18

Plus-sizing from 225/45 R17 to 275/35 R18 keeps overall diameter close to factory while opening room for a larger 18-inch wheel. This wheel and tire pairing moves rolling diameter a touch off the original spec.

Expect a slight but noticeable shift in indicated speed compared to the original tires. Expect a more planted steering feel, at the cost of some of the cushioning a taller sidewall provides. Extra width broadens the footprint for more grip, but check inner liner and strut clearance before fitting. The larger wheel shows more of the brake hardware and tightens up the wheel-gap look. 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: 275/35 R18 is 15.4 mm taller than 225/45 R17, shifting the speedometer by +2.43%.

Current Tire

225/45R17

New Tire

275/35R18
225/45 R17
275/35 R18

Ground line · scaled comparison

Excellent Fit

Within ±3% — safe for daily driving

Diameter change

+15.4 mm

2.43%

Speedometer at 100

102.4 km/h

+2.43% error

Ground clearance

+7.7 mm

ride height delta

Sidewall change

-5.0 mm

revs/km: 489.9

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Detailed comparison

Metric225/45 R17275/35 R18Difference
Overall diameter634.3 mm649.7 mm+15.4 mm (+2.43%)
Sidewall height101.3 mm96.3 mm-5.0 mm
Circumference1.993 m2.041 m+48.4 mm
Revs / km501.8489.9-11.9
Ground clearancereference+7.7 mm+7.7 mm
Speedometer @ 100 km/h100.0 km/h102.4 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 102.4 km/h after switching to 275/35 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 +7.7 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

225/45 R17

Back to

275/35 R18

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