Comparison
245/40 R20 vs 265/40 R20
Stepping from 245/40 R20 to 265/40 R20 keeps the 20-inch wheel but widens the section by 20 mm. 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. Extra width broadens the footprint for more grip, but check inner liner and strut clearance before fitting. Diameter change stays inside the conservative ±3% safety window — an OEM-safe fitment on most vehicles.
TakeReasonable performance-leaning swap as long as fender and suspension clearance check out.
Quick math: 265/40 R20 is 16.0 mm taller than 245/40 R20, shifting the speedometer by +2.27%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
+16.0 mm
2.27%
Speedometer at 100
102.3 km/h
+2.27% error
Ground clearance
+8.0 mm
ride height delta
Sidewall change
+8.0 mm
revs/km: 442.1
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/compare/245-40-r20-vs-265-40-r20Detailed comparison
| Metric | 245/40 R20 | 265/40 R20 | Difference |
|---|---|---|---|
| Overall diameter | 704.0 mm | 720.0 mm | +16.0 mm (+2.27%) |
| Sidewall height | 98.0 mm | 106.0 mm | +8.0 mm |
| Circumference | 2.212 m | 2.262 m | +50.3 mm |
| Revs / km | 452.1 | 442.1 | -10.0 |
| Ground clearance | reference | +8.0 mm | +8.0 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 102.3 km/h | +2.27 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 102.3 km/h after switching to 265/40 R20 — a +2.27% 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 +8.0 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
245/40 R20
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265/40 R20
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