Comparison

255/35 R18 vs 275/35 R18

On the same 18-inch wheel, 275/35 R18 grows the section width by 20 mm versus 255/35 R18. This sizing approach shifts overall diameter slightly from OEM. The speedometer offset is small but measurable; worth keeping in mind if you watch the dash closely. The wider section adds contact patch and lateral stability, while eating into fender and suspension clearance. Overall the swap sits inside the safe ±3% diameter window, so ABS, traction control and gearing behave normally.

TakeReasonable performance-leaning swap as long as fender and suspension clearance check out.

Quick math: 275/35 R18 is 14.0 mm taller than 255/35 R18, shifting the speedometer by +2.20%.

Current Tire

255/35R18

New Tire

275/35R18
255/35 R18
275/35 R18

Ground line · scaled comparison

Excellent Fit

Within ±3% — safe for daily driving

Diameter change

+14.0 mm

2.20%

Speedometer at 100

102.2 km/h

+2.20% error

Ground clearance

+7.0 mm

ride height delta

Sidewall change

+7.0 mm

revs/km: 489.9

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Detailed comparison

Metric255/35 R18275/35 R18Difference
Overall diameter635.7 mm649.7 mm+14.0 mm (+2.20%)
Sidewall height89.3 mm96.3 mm+7.0 mm
Circumference1.997 m2.041 m+44.0 mm
Revs / km500.7489.9-10.8
Ground clearancereference+7.0 mm+7.0 mm
Speedometer @ 100 km/h100.0 km/h102.2 km/h+2.20 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 102.2 km/h after switching to 275/35 R18 — a +2.20% 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 +7.0 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.

Back to

255/35 R18

Back to

275/35 R18

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