Comparison

245/35 R18 vs 275/35 R18

Stepping from 245/35 R18 to 275/35 R18 keeps the 18-inch wheel but widens the section by 30 mm. This alternative fitment moves rolling diameter well outside the usual OEM tolerance.

The speedometer error is noticeable and may warrant a recalibration if you rely on indicated speed. Extra width broadens the footprint for more grip, but check inner liner and strut clearance before fitting. Diameter delta falls in the cautious 3–5% range, where speedometer recalibration and a careful clearance check are worth doing.

TakeUseful when extra dry grip and stance matter more than a small fuel-economy hit.

Quick math: 275/35 R18 is 21.0 mm taller than 245/35 R18, shifting the speedometer by +3.34%.

Current Tire

245/35R18

New Tire

275/35R18
245/35 R18
275/35 R18

Ground line · scaled comparison

Slight Difference

Within ±5% — usable, recalibration recommended

Diameter change

+21.0 mm

3.34%

Speedometer at 100

103.3 km/h

+3.34% error

Ground clearance

+10.5 mm

ride height delta

Sidewall change

+10.5 mm

revs/km: 489.9

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Detailed comparison

Metric245/35 R18275/35 R18Difference
Overall diameter628.7 mm649.7 mm+21.0 mm (+3.34%)
Sidewall height85.8 mm96.3 mm+10.5 mm
Circumference1.975 m2.041 m+66.0 mm
Revs / km506.3489.9-16.4
Ground clearancereference+10.5 mm+10.5 mm
Speedometer @ 100 km/h100.0 km/h103.3 km/h+3.34 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 103.3 km/h after switching to 275/35 R18 — a +3.34% 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 +10.5 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

245/35 R18

Back to

275/35 R18

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Frequently asked questions