Comparison
245/45 R20 vs 255/45 R19
Switching from 245/45 R20 to 255/45 R19 steps down to a 19-inch wheel — a familiar move for winter and dedicated all-terrain sets. This wheel and tire pairing shifts overall diameter slightly from OEM.
The speedometer offset is small but measurable; worth keeping in mind if you watch the dash closely. More tread on the ground tends to improve dry grip and stance, with a small fuel-economy and clearance tradeoff. Minus-sizing keeps replacement costs down and opens up a wider range of winter and all-terrain tires. Diameter change stays inside the conservative ±3% safety window — an OEM-safe fitment on most vehicles.
TakeTypical choice for a dedicated winter or off-road setup where extra sidewall pays off.
Quick math: 255/45 R19 is 16.4 mm shorter than 245/45 R20, shifting the speedometer by -2.25%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
-16.4 mm
-2.25%
Speedometer at 100
97.7 km/h
-2.25% error
Ground clearance
-8.2 mm
ride height delta
Sidewall change
+4.5 mm
revs/km: 447.0
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/compare/245-45-r20-vs-255-45-r19Detailed comparison
| Metric | 245/45 R20 | 255/45 R19 | Difference |
|---|---|---|---|
| Overall diameter | 728.5 mm | 712.1 mm | -16.4 mm (-2.25%) |
| Sidewall height | 110.3 mm | 114.8 mm | +4.5 mm |
| Circumference | 2.289 m | 2.237 m | -51.5 mm |
| Revs / km | 436.9 | 447.0 | +10.1 |
| Ground clearance | reference | -8.2 mm | -8.2 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 97.7 km/h | -2.25 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 97.7 km/h after switching to 255/45 R19 — a -2.25% 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 -8.2 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 R20
Back to
255/45 R19
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