Comparison
245/45 R18 vs 275/35 R18
Switching from 245/45 R18 to 275/35 R18 drops the aspect ratio by 10 points on the same 18-inch wheel. This alternative fitment swings rolling diameter far enough to feel on the road.
Indicated speed will drift far enough that recalibration is worth considering. 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. Diameter delta falls in the cautious 3–5% range, where speedometer recalibration and a careful clearance check are worth doing.
TakeSuits drivers who value sharper steering and appearance over outright ride softness.
Quick math: 275/35 R18 is 28.0 mm shorter than 245/45 R18, shifting the speedometer by -4.13%.
Current Tire
New Tire
Ground line · scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
-28.0 mm
-4.13%
Speedometer at 100
95.9 km/h
-4.13% error
Ground clearance
-14.0 mm
ride height delta
Sidewall change
-14.0 mm
revs/km: 489.9
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/compare/245-45-r18-vs-275-35-r18Detailed comparison
| Metric | 245/45 R18 | 275/35 R18 | Difference |
|---|---|---|---|
| Overall diameter | 677.7 mm | 649.7 mm | -28.0 mm (-4.13%) |
| Sidewall height | 110.3 mm | 96.3 mm | -14.0 mm |
| Circumference | 2.129 m | 2.041 m | -88.0 mm |
| Revs / km | 469.7 | 489.9 | +20.2 |
| Ground clearance | reference | -14.0 mm | -14.0 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 95.9 km/h | -4.13 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 95.9 km/h after switching to 275/35 R18 — a -4.13% 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 -14.0 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
245/45 R18
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275/35 R18
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