Comparison
255/50 R19 vs 265/40 R20
Plus-sizing from 255/50 R19 to 265/40 R20 keeps overall diameter close to factory while opening room for a larger 20-inch wheel. This alternative fitment moves rolling diameter a touch off the original spec. Less sidewall flex usually translates to crisper turn-in and a slightly stiffer ride over rough pavement.
Expect a slight but noticeable shift in indicated speed compared to the original tires. Diameter change stays inside the conservative ±3% safety window — an OEM-safe fitment on most vehicles.
TakeA solid pick for drivers chasing a more aggressive stance without abandoning OEM rolling diameter.
Quick math: 265/40 R20 is 17.6 mm shorter than 255/50 R19, shifting the speedometer by -2.39%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
-17.6 mm
-2.39%
Speedometer at 100
97.6 km/h
-2.39% error
Ground clearance
-8.8 mm
ride height delta
Sidewall change
-21.5 mm
revs/km: 442.1
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/compare/255-50-r19-vs-265-40-r20Detailed comparison
| Metric | 255/50 R19 | 265/40 R20 | Difference |
|---|---|---|---|
| Overall diameter | 737.6 mm | 720.0 mm | -17.6 mm (-2.39%) |
| Sidewall height | 127.5 mm | 106.0 mm | -21.5 mm |
| Circumference | 2.317 m | 2.262 m | -55.3 mm |
| Revs / km | 431.5 | 442.1 | +10.5 |
| Ground clearance | reference | -8.8 mm | -8.8 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 97.6 km/h | -2.39 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 97.6 km/h after switching to 265/40 R20 — a -2.39% 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 -8.8 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
255/50 R19
Back to
265/40 R20
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