Comparison

235/35 R19 vs 255/35 R18

255/35 R18 drops the rim from 19 to 18 inches versus 235/35 R19, trading wheel size for taller sidewall. This sizing approach moves rolling diameter a touch off the original spec.

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. 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.

TakePractical direction for winter wheels, chains, or rougher pavement where cushioning matters.

Quick math: 255/35 R18 is 11.4 mm shorter than 235/35 R19, shifting the speedometer by -1.76%.

Current Tire

235/35R19

New Tire

255/35R18
235/35 R19
255/35 R18

Ground line · scaled comparison

Excellent Fit

Within ±3% — safe for daily driving

Diameter change

-11.4 mm

-1.76%

Speedometer at 100

98.2 km/h

-1.76% error

Ground clearance

-5.7 mm

ride height delta

Sidewall change

+7.0 mm

revs/km: 500.7

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Detailed comparison

Metric235/35 R19255/35 R18Difference
Overall diameter647.1 mm635.7 mm-11.4 mm (-1.76%)
Sidewall height82.3 mm89.3 mm+7.0 mm
Circumference2.033 m1.997 m-35.8 mm
Revs / km491.9500.7+8.8
Ground clearancereference-5.7 mm-5.7 mm
Speedometer @ 100 km/h100.0 km/h98.2 km/h-1.76 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 98.2 km/h after switching to 255/35 R18 — a -1.76% 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 -5.7 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

235/35 R19

Back to

255/35 R18

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